diff --git a/acceptance_tests/acceptance_suite_test.go b/acceptance_tests/acceptance_suite_test.go
index 6b14bb506..6f4ac8764 100644
--- a/acceptance_tests/acceptance_suite_test.go
+++ b/acceptance_tests/acceptance_suite_test.go
@@ -14,10 +14,9 @@ import (
 	. "github.com/onsi/gomega"
 	"github.com/onsi/gomega/gbytes"
 	"github.com/onsi/gomega/gexec"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/lib/ginkgoutil"
 	"github.com/yandex/pandora/lib/tag"
+	"go.uber.org/zap"
 )
 
 var pandoraBin string
diff --git a/acceptance_tests/http_test.go b/acceptance_tests/http_test.go
index ab71fd37d..fea9dc757 100644
--- a/acceptance_tests/http_test.go
+++ b/acceptance_tests/http_test.go
@@ -2,14 +2,12 @@ package acceptance
 
 import (
 	"net/http"
-
-	"golang.org/x/net/http2"
-
 	"net/http/httptest"
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"go.uber.org/atomic"
+	"golang.org/x/net/http2"
 )
 
 var _ = Describe("http", func() {
diff --git a/cli/cli.go b/cli/cli.go
index f2659c30a..2310e55d2 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -17,15 +17,14 @@ import (
 	"time"
 
 	"github.com/spf13/viper"
-	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
-
 	"github.com/yandex/pandora/core/config"
 	"github.com/yandex/pandora/core/engine"
 	"github.com/yandex/pandora/lib/zaputil"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
 )
 
-const Version = "0.3.5"
+const Version = "0.4.0"
 const defaultConfigFile = "load"
 const stdinConfigSelector = "-"
 
@@ -129,30 +128,41 @@ func Run() {
 	errs := make(chan error)
 	go runEngine(ctx, pandora, errs)
 
+	// waiting for signal or error message from engine
+	awaitPandoraTermination(pandora, cancel, errs, log)
+	log.Info("Engine run successfully finished")
+}
+
+// helper function that awaits pandora run
+func awaitPandoraTermination(pandora *engine.Engine, gracefulShutdown func(), errs chan error, log *zap.Logger) {
 	sigs := make(chan os.Signal, 2)
 	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
 
-	// waiting for signal or error message from engine
 	select {
 	case sig := <-sigs:
+		var interruptTimeout = 3 * time.Second
 		switch sig {
 		case syscall.SIGINT:
-			const interruptTimeout = 5 * time.Second
-			log.Info("SIGINT received. Trying to stop gracefully.", zap.Duration("timeout", interruptTimeout))
-			cancel()
-			select {
-			case <-time.After(interruptTimeout):
-				log.Fatal("Interrupt timeout exceeded")
-			case sig := <-sigs:
-				log.Fatal("Another signal received. Quiting.", zap.Stringer("signal", sig))
-			case err := <-errs:
-				log.Fatal("Engine interrupted", zap.Error(err))
-			}
+			// await gun timeout but no longer than 30 sec.
+			interruptTimeout = 30 * time.Second
+			log.Info("SIGINT received. Graceful shutdown.", zap.Duration("timeout", interruptTimeout))
+			gracefulShutdown()
 		case syscall.SIGTERM:
-			log.Fatal("SIGTERM received. Quiting.")
+			log.Info("SIGTERM received. Trying to stop gracefully.", zap.Duration("timeout", interruptTimeout))
+			gracefulShutdown()
 		default:
 			log.Fatal("Unexpected signal received. Quiting.", zap.Stringer("signal", sig))
 		}
+
+		select {
+		case <-time.After(interruptTimeout):
+			log.Fatal("Interrupt timeout exceeded")
+		case sig := <-sigs:
+			log.Fatal("Another signal received. Quiting.", zap.Stringer("signal", sig))
+		case err := <-errs:
+			log.Fatal("Engine interrupted", zap.Error(err))
+		}
+
 	case err := <-errs:
 		switch err {
 		case nil:
@@ -160,7 +170,7 @@ func Run() {
 		case err:
 			const awaitTimeout = 3 * time.Second
 			log.Error("Engine run failed. Awaiting started tasks.", zap.Error(err), zap.Duration("timeout", awaitTimeout))
-			cancel()
+			gracefulShutdown()
 			time.AfterFunc(awaitTimeout, func() {
 				log.Fatal("Engine tasks timeout exceeded.")
 			})
@@ -168,7 +178,6 @@ func Run() {
 			log.Fatal("Engine run failed. Pandora graceful shutdown successfully finished")
 		}
 	}
-	log.Info("Engine run successfully finished")
 }
 
 func runEngine(ctx context.Context, engine *engine.Engine, errs chan error) {
diff --git a/cli/expvar.go b/cli/expvar.go
index ed8f436d9..054ffe9f1 100644
--- a/cli/expvar.go
+++ b/cli/expvar.go
@@ -3,10 +3,9 @@ package cli
 import (
 	"time"
 
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core/engine"
 	"github.com/yandex/pandora/lib/monitoring"
+	"go.uber.org/zap"
 )
 
 func newEngineMetrics() engine.Metrics {
diff --git a/components/example/example.go b/components/example/example.go
index f6dab2222..c5515f787 100644
--- a/components/example/example.go
+++ b/components/example/example.go
@@ -10,10 +10,9 @@ import (
 	"fmt"
 	"sync"
 
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator/netsample"
+	"go.uber.org/zap"
 )
 
 type Ammo struct {
diff --git a/components/grpc/ammo/grpcjson/provider.go b/components/grpc/ammo/grpcjson/provider.go
index 79c3e5dcd..067012fec 100644
--- a/components/grpc/ammo/grpcjson/provider.go
+++ b/components/grpc/ammo/grpcjson/provider.go
@@ -9,13 +9,12 @@ import (
 	"bufio"
 	"context"
 
-	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
-	"github.com/yandex/pandora/components/grpc/ammo"
-
 	jsoniter "github.com/json-iterator/go"
+	"github.com/pkg/errors"
 	"github.com/spf13/afero"
+	"github.com/yandex/pandora/components/grpc/ammo"
+	"github.com/yandex/pandora/lib/confutil"
+	"go.uber.org/zap"
 )
 
 func NewProvider(fs afero.Fs, conf Config) *Provider {
@@ -51,6 +50,7 @@ type Config struct {
 	//Maximum number of byte in an ammo. Default is bufio.MaxScanTokenSize
 	MaxAmmoSize int
 	Source      Source `config:"source"`
+	ChosenCases []string
 }
 
 func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
@@ -72,6 +72,9 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 					return errors.Wrapf(err, "failed to decode ammo at line: %v; data: %q", line, data)
 				}
 			}
+			if !confutil.IsChosenCase(a.Tag, p.Config.ChosenCases) {
+				continue
+			}
 			ammoNum++
 			select {
 			case p.Sink <- a:
diff --git a/components/grpc/ammo/provider.go b/components/grpc/ammo/provider.go
index e390b1947..120a1258c 100644
--- a/components/grpc/ammo/provider.go
+++ b/components/grpc/ammo/provider.go
@@ -11,9 +11,8 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-	"go.uber.org/atomic"
-
 	"github.com/yandex/pandora/core"
+	"go.uber.org/atomic"
 )
 
 func NewProvider(fs afero.Fs, fileName string, start func(ctx context.Context, file afero.File) error) Provider {
diff --git a/components/grpc/core.go b/components/grpc/core.go
index 5fa5a9340..ab7bf0beb 100644
--- a/components/grpc/core.go
+++ b/components/grpc/core.go
@@ -8,22 +8,20 @@ import (
 	"log"
 	"time"
 
+	"github.com/jhump/protoreflect/desc"
+	"github.com/jhump/protoreflect/dynamic"
+	"github.com/jhump/protoreflect/dynamic/grpcdynamic"
 	"github.com/jhump/protoreflect/grpcreflect"
-	"github.com/yandex/pandora/core/warmup"
-	"google.golang.org/grpc/credentials"
-	reflectpb "google.golang.org/grpc/reflection/grpc_reflection_v1alpha"
-
 	"github.com/yandex/pandora/components/grpc/ammo"
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator/netsample"
-
-	"github.com/jhump/protoreflect/desc"
-	"github.com/jhump/protoreflect/dynamic"
-	"github.com/jhump/protoreflect/dynamic/grpcdynamic"
+	"github.com/yandex/pandora/core/warmup"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/metadata"
+	reflectpb "google.golang.org/grpc/reflection/grpc_reflection_v1alpha"
 	"google.golang.org/grpc/status"
 )
 
@@ -33,7 +31,8 @@ type Sample struct {
 }
 
 type grpcDialOptions struct {
-	Authority string `config:"authority"`
+	Authority string        `config:"authority"`
+	Timeout   time.Duration `config:"timeout"`
 }
 
 type GunConfig struct {
@@ -186,7 +185,11 @@ func makeGRPCConnect(target string, isTLS bool, dialOptions grpcDialOptions) (co
 	} else {
 		opts = append(opts, grpc.WithInsecure())
 	}
-	opts = append(opts, grpc.WithTimeout(time.Second))
+	timeout := time.Second
+	if dialOptions.Timeout != 0 {
+		timeout = dialOptions.Timeout
+	}
+	opts = append(opts, grpc.WithTimeout(timeout))
 	opts = append(opts, grpc.WithUserAgent("load test, pandora universal grpc shooter"))
 
 	if dialOptions.Authority != "" {
diff --git a/components/phttp/ammo/simple/ammo.go b/components/phttp/ammo/simple/ammo.go
index 6db888e39..5fdc5e756 100644
--- a/components/phttp/ammo/simple/ammo.go
+++ b/components/phttp/ammo/simple/ammo.go
@@ -51,4 +51,8 @@ func (a *Ammo) IsValid() bool {
 	return !a.isInvalid
 }
 
+func (a *Ammo) Tag() string {
+	return a.tag
+}
+
 var _ phttp.Ammo = (*Ammo)(nil)
diff --git a/components/phttp/ammo/simple/jsonline/jsonline_suite_test.go b/components/phttp/ammo/simple/jsonline/jsonline_suite_test.go
index d149cd1b7..bcdc60ec4 100644
--- a/components/phttp/ammo/simple/jsonline/jsonline_suite_test.go
+++ b/components/phttp/ammo/simple/jsonline/jsonline_suite_test.go
@@ -17,7 +17,6 @@ import (
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/lib/ginkgoutil"
diff --git a/components/phttp/ammo/simple/jsonline/provider.go b/components/phttp/ammo/simple/jsonline/provider.go
index 0a999a8b5..25c5f540f 100644
--- a/components/phttp/ammo/simple/jsonline/provider.go
+++ b/components/phttp/ammo/simple/jsonline/provider.go
@@ -12,10 +12,10 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/spf13/afero"
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
+	"github.com/yandex/pandora/lib/confutil"
+	"go.uber.org/zap"
 )
 
 func NewProvider(fs afero.Fs, conf Config) *Provider {
@@ -42,10 +42,12 @@ type Config struct {
 	ContinueOnError bool
 	//Maximum number of byte in an ammo. Default is bufio.MaxScanTokenSize
 	MaxAmmoSize int
+	ChosenCases []string
 }
 
 func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 	var ammoNum, passNum int
+
 	for {
 		passNum++
 		scanner := bufio.NewScanner(ammoFile)
@@ -63,6 +65,9 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 					return errors.Wrapf(err, "failed to decode ammo at line: %v; data: %q", line, data)
 				}
 			}
+			if !confutil.IsChosenCase(a.Tag(), p.Config.ChosenCases) {
+				continue
+			}
 			ammoNum++
 			select {
 			case p.Sink <- a:
diff --git a/components/phttp/ammo/simple/provider.go b/components/phttp/ammo/simple/provider.go
index 117fafa4f..70ebda16f 100644
--- a/components/phttp/ammo/simple/provider.go
+++ b/components/phttp/ammo/simple/provider.go
@@ -11,9 +11,8 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-	"go.uber.org/atomic"
-
 	"github.com/yandex/pandora/core"
+	"go.uber.org/atomic"
 )
 
 func NewProvider(fs afero.Fs, fileName string, start func(ctx context.Context, file afero.File) error) Provider {
diff --git a/components/phttp/ammo/simple/raw/decoder.go b/components/phttp/ammo/simple/raw/decoder.go
index b6b7e63e5..e34481d68 100644
--- a/components/phttp/ammo/simple/raw/decoder.go
+++ b/components/phttp/ammo/simple/raw/decoder.go
@@ -6,8 +6,6 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
-
-	"github.com/pkg/errors"
 )
 
 type Header struct {
@@ -29,30 +27,6 @@ func decodeRequest(reqString []byte) (req *http.Request, err error) {
 	if err != nil {
 		return
 	}
-	if req.Host != "" {
-		req.URL.Host = req.Host
-	}
 	req.RequestURI = ""
 	return
 }
-
-func decodeHTTPConfigHeaders(headers []string) (configHTTPHeaders []Header, err error) {
-	for _, header := range headers {
-		line := []byte(header)
-		if len(line) < 3 || line[0] != '[' || line[len(line)-1] != ']' {
-			return nil, errors.New("header line should be like '[key: value]")
-		}
-		line = line[1 : len(line)-1]
-		colonIdx := bytes.IndexByte(line, ':')
-		if colonIdx < 0 {
-			return nil, errors.New("missing colon")
-		}
-		configHTTPHeaders = append(
-			configHTTPHeaders,
-			Header{
-				string(bytes.TrimSpace(line[:colonIdx])),
-				string(bytes.TrimSpace(line[colonIdx+1:])),
-			})
-	}
-	return
-}
diff --git a/components/phttp/ammo/simple/raw/decoder_bench_test.go b/components/phttp/ammo/simple/raw/decoder_bench_test.go
index 6b6745572..adf049f4d 100644
--- a/components/phttp/ammo/simple/raw/decoder_bench_test.go
+++ b/components/phttp/ammo/simple/raw/decoder_bench_test.go
@@ -1,6 +1,10 @@
 package raw
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/yandex/pandora/components/phttp/ammo/simple"
+)
 
 var (
 	benchTestConfigHeaders = []string{
@@ -27,16 +31,10 @@ func BenchmarkRawDecoder(b *testing.B) {
 
 func BenchmarkRawDecoderWithHeaders(b *testing.B) {
 	b.StopTimer()
-	decodedHTTPConfigHeaders, _ := decodeHTTPConfigHeaders(benchTestConfigHeaders)
+	decodedHTTPConfigHeaders, _ := simple.DecodeHTTPConfigHeaders(benchTestConfigHeaders)
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		req, _ := decodeRequest([]byte(benchTestRequest))
-		for _, header := range decodedHTTPConfigHeaders {
-			if header.key == "Host" {
-				req.URL.Host = header.value
-			} else {
-				req.Header.Set(header.key, header.value)
-			}
-		}
+		simple.UpdateRequestWithHeaders(req, decodedHTTPConfigHeaders)
 	}
 }
diff --git a/components/phttp/ammo/simple/raw/decoder_test.go b/components/phttp/ammo/simple/raw/decoder_test.go
index 5f8fb7673..696522f20 100644
--- a/components/phttp/ammo/simple/raw/decoder_test.go
+++ b/components/phttp/ammo/simple/raw/decoder_test.go
@@ -83,34 +83,5 @@ var _ = Describe("Decoder", func() {
 		req, err := decodeRequest([]byte(raw))
 		Expect(err).To(BeNil())
 		Expect(req.Host).To(Equal("hostname.tld"))
-		Expect(req.URL.Host).To(Equal("hostname.tld"))
-	})
-	It("should replace header Host from config", func() {
-		const host = "hostname.tld"
-		const newhost = "newhostname.tld"
-
-		raw := "GET / HTTP/1.1\r\n" +
-			"Host: " + host + "\r\n" +
-			"Content-Length: 0\r\n" +
-			"\r\n"
-		configHeaders := []string{
-			"[Host: " + newhost + "]",
-			"[SomeTestKey: sometestvalue]",
-		}
-		req, err := decodeRequest([]byte(raw))
-		Expect(err).To(BeNil())
-		Expect(req.Host).To(Equal(host))
-		Expect(req.URL.Host).To(Equal(host))
-		decodedConfigHeaders, _ := decodeHTTPConfigHeaders(configHeaders)
-		for _, header := range decodedConfigHeaders {
-			// special behavior for `Host` header
-			if header.key == "Host" {
-				req.URL.Host = header.value
-			} else {
-				req.Header.Set(header.key, header.value)
-			}
-		}
-		Expect(req.URL.Host).To(Equal(newhost))
-		Expect(req.Header.Get("SomeTestKey")).To(Equal("sometestvalue"))
 	})
 })
diff --git a/components/phttp/ammo/simple/raw/provider.go b/components/phttp/ammo/simple/raw/provider.go
index 428f42a95..25100bb4e 100644
--- a/components/phttp/ammo/simple/raw/provider.go
+++ b/components/phttp/ammo/simple/raw/provider.go
@@ -7,9 +7,9 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
+	"github.com/yandex/pandora/lib/confutil"
+	"go.uber.org/zap"
 )
 
 /*
@@ -54,7 +54,8 @@ type Config struct {
 	// Redefine HTTP headers
 	Headers []string
 	// Passes limits ammo file passes. Unlimited if zero.
-	Passes int `validate:"min=0"`
+	Passes      int `validate:"min=0"`
+	ChosenCases []string
 }
 
 func NewProvider(fs afero.Fs, conf Config) *Provider {
@@ -76,7 +77,7 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 	var passNum int
 	var ammoNum int
 	// parse and prepare Headers from config
-	decodedConfigHeaders, err := decodeHTTPConfigHeaders(p.Config.Headers)
+	decodedConfigHeaders, err := simple.DecodeHTTPConfigHeaders(p.Config.Headers)
 	if err != nil {
 		return err
 	}
@@ -101,6 +102,9 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 			if reqSize == 0 {
 				break // start over from the beginning of file if ammo size is 0
 			}
+			if !confutil.IsChosenCase(tag, p.Config.ChosenCases) {
+				continue
+			}
 			buff := make([]byte, reqSize)
 			if n, err := io.ReadFull(reader, buff); err != nil {
 				return errors.Wrapf(err, "failed to read ammo at position: %v; tried to read: %v; have read: %v", filePosition(ammoFile), reqSize, n)
@@ -110,15 +114,8 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 				return errors.Wrapf(err, "failed to decode ammo at position: %v; data: %q", filePosition(ammoFile), buff)
 			}
 
-			// redefine request Headers from config
-			for _, header := range decodedConfigHeaders {
-				// special behavior for `Host` header
-				if header.key == "Host" {
-					req.URL.Host = header.value
-				} else {
-					req.Header.Set(header.key, header.value)
-				}
-			}
+			// add new Headers to request from config
+			simple.UpdateRequestWithHeaders(req, decodedConfigHeaders)
 
 			sh := p.Pool.Get().(*simple.Ammo)
 			sh.Reset(req, tag)
diff --git a/components/phttp/ammo/simple/raw/provider_test.go b/components/phttp/ammo/simple/raw/provider_test.go
index 547068f39..d73931d38 100644
--- a/components/phttp/ammo/simple/raw/provider_test.go
+++ b/components/phttp/ammo/simple/raw/provider_test.go
@@ -13,7 +13,6 @@ import (
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
 	"github.com/yandex/pandora/core"
 )
diff --git a/components/phttp/ammo/simple/request.go b/components/phttp/ammo/simple/request.go
new file mode 100644
index 000000000..08e2f1f90
--- /dev/null
+++ b/components/phttp/ammo/simple/request.go
@@ -0,0 +1,56 @@
+// Copyright (c) 2017 Yandex LLC. All rights reserved.
+// Use of this source code is governed by a MPL 2.0
+// license that can be found in the LICENSE file.
+// Author: Vladimir Skipor <skipor@yandex-team.ru>
+
+package simple
+
+import (
+	"bytes"
+	"net/http"
+
+	"github.com/pkg/errors"
+)
+
+type Header struct {
+	key   string
+	value string
+}
+
+func DecodeHTTPConfigHeaders(headers []string) (configHTTPHeaders []Header, err error) {
+	for _, header := range headers {
+		line := []byte(header)
+		if len(line) < 3 || line[0] != '[' || line[len(line)-1] != ']' {
+			return nil, errors.New("header line should be like '[key: value]")
+		}
+		line = line[1 : len(line)-1]
+		colonIdx := bytes.IndexByte(line, ':')
+		if colonIdx < 0 {
+			return nil, errors.New("missing colon")
+		}
+		configHTTPHeaders = append(
+			configHTTPHeaders,
+			Header{
+				string(bytes.TrimSpace(line[:colonIdx])),
+				string(bytes.TrimSpace(line[colonIdx+1:])),
+			})
+	}
+	return
+}
+
+func UpdateRequestWithHeaders(req *http.Request, headers []Header) {
+	origHeaders := req.Header.Clone()
+	for _, header := range headers {
+		if origHeaders.Get(header.key) != "" {
+			continue
+		}
+		// special behavior for `Host` header
+		if header.key == "Host" {
+			if req.Host == "" {
+				req.Host = header.value
+			}
+		} else {
+			req.Header.Add(header.key, header.value)
+		}
+	}
+}
diff --git a/components/phttp/ammo/simple/uri/decoder.go b/components/phttp/ammo/simple/uri/decoder.go
index 4a66b2a2e..30aa6c51e 100644
--- a/components/phttp/ammo/simple/uri/decoder.go
+++ b/components/phttp/ammo/simple/uri/decoder.go
@@ -13,8 +13,8 @@ import (
 	"sync"
 
 	"github.com/pkg/errors"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
+	"github.com/yandex/pandora/lib/confutil"
 )
 
 type decoder struct {
@@ -24,20 +24,17 @@ type decoder struct {
 
 	ammoNum       int
 	header        http.Header
-	configHeaders []ConfigHeader
-}
-
-type ConfigHeader struct {
-	key   string
-	value string
+	configHeaders []simple.Header
+	chosenCases   []string
 }
 
-func newDecoder(ctx context.Context, sink chan<- *simple.Ammo, pool *sync.Pool) *decoder {
+func newDecoder(ctx context.Context, sink chan<- *simple.Ammo, pool *sync.Pool, chosenCases []string) *decoder {
 	return &decoder{
-		sink:   sink,
-		header: http.Header{},
-		pool:   pool,
-		ctx:    ctx,
+		sink:        sink,
+		header:      http.Header{},
+		pool:        pool,
+		ctx:         ctx,
+		chosenCases: chosenCases,
 	}
 }
 
@@ -62,6 +59,9 @@ func (d *decoder) decodeURI(line []byte) error {
 	if len(parts) > 1 {
 		tag = parts[1]
 	}
+	if !confutil.IsChosenCase(tag, d.chosenCases) {
+		return nil
+	}
 	req, err := http.NewRequest("GET", string(url), nil)
 	if err != nil {
 		return errors.Wrap(err, "uri decode")
@@ -70,20 +70,13 @@ func (d *decoder) decodeURI(line []byte) error {
 		// http.Request.Write sends Host header based on req.URL.Host
 		if k == "Host" {
 			req.Host = v[0]
-			req.URL.Host = v[0]
 		} else {
 			req.Header[k] = v
 		}
 	}
-	// redefine request Headers from config
-	for _, configHeader := range d.configHeaders {
-		if configHeader.key == "Host" {
-			req.Host = configHeader.value
-			req.URL.Host = configHeader.value
-		} else {
-			req.Header.Set(configHeader.key, configHeader.value)
-		}
-	}
+
+	// add new Headers to request from config
+	simple.UpdateRequestWithHeaders(req, d.configHeaders)
 
 	sh := d.pool.Get().(*simple.Ammo)
 	sh.Reset(req, tag)
@@ -119,23 +112,3 @@ func (d *decoder) ResetHeader() {
 		delete(d.header, k)
 	}
 }
-
-func decodeHTTPConfigHeaders(headers []string) (configHTTPHeaders []ConfigHeader, err error) {
-	for _, header := range headers {
-		line := []byte(header)
-		if len(line) < 3 || line[0] != '[' || line[len(line)-1] != ']' {
-			return nil, errors.New("header line should be like '[key: value]")
-		}
-		line = line[1 : len(line)-1]
-		colonIdx := bytes.IndexByte(line, ':')
-		if colonIdx < 0 {
-			return nil, errors.New("missing colon")
-		}
-		preparedHeader := ConfigHeader{
-			string(bytes.TrimSpace(line[:colonIdx])),
-			string(bytes.TrimSpace(line[colonIdx+1:])),
-		}
-		configHTTPHeaders = append(configHTTPHeaders, preparedHeader)
-	}
-	return
-}
diff --git a/components/phttp/ammo/simple/uri/decoder_test.go b/components/phttp/ammo/simple/uri/decoder_test.go
index 4a35ebcdd..c3b731218 100644
--- a/components/phttp/ammo/simple/uri/decoder_test.go
+++ b/components/phttp/ammo/simple/uri/decoder_test.go
@@ -9,7 +9,6 @@ import (
 	. "github.com/onsi/ginkgo/extensions/table"
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
 	"github.com/yandex/pandora/core"
 )
@@ -22,7 +21,7 @@ func newAmmoPool() *sync.Pool {
 var _ = Describe("Decoder", func() {
 	It("uri decode ctx cancel", func() {
 		ctx, cancel := context.WithCancel(context.Background())
-		decoder := newDecoder(ctx, make(chan *simple.Ammo), newAmmoPool())
+		decoder := newDecoder(ctx, make(chan *simple.Ammo), newAmmoPool(), nil)
 		cancel()
 		err := decoder.Decode([]byte("/some/path"))
 		Expect(err).To(Equal(context.Canceled))
@@ -33,7 +32,7 @@ var _ = Describe("Decoder", func() {
 	)
 	BeforeEach(func() {
 		ammoCh = make(chan *simple.Ammo, 10)
-		decoder = newDecoder(context.Background(), ammoCh, newAmmoPool())
+		decoder = newDecoder(context.Background(), ammoCh, newAmmoPool(), nil)
 	})
 	DescribeTable("invalid input",
 		func(line string) {
@@ -69,7 +68,6 @@ var _ = Describe("Decoder", func() {
 		req, sample := sh.Request()
 		Expect(*req.URL).To(MatchFields(IgnoreExtras, Fields{
 			"Path":   Equal(line),
-			"Host":   Equal(host),
 			"Scheme": BeEmpty(),
 		}))
 		Expect(req.Host).To(Equal(host))
@@ -95,7 +93,6 @@ var _ = Describe("Decoder", func() {
 		req, sample := sh.Request()
 		Expect(*req.URL).To(MatchFields(IgnoreExtras, Fields{
 			"Path":   Equal("/some/path"),
-			"Host":   Equal(host),
 			"Scheme": BeEmpty(),
 		}))
 		Expect(req.Host).To(Equal(host))
@@ -142,18 +139,6 @@ var _ = Describe("Decoder", func() {
 				"C": []string{""},
 			}))
 		})
-		It("overwrite by config", func() {
-			decodedConfigHeaders, _ := decodeHTTPConfigHeaders([]string{
-				"[Host: youhost.tld]",
-				"[SomeHeader: somevalue]",
-			})
-			decoder.configHeaders = decodedConfigHeaders
-			cfgHeaders := []ConfigHeader{
-				{"Host", "youhost.tld"},
-				{"SomeHeader", "somevalue"},
-			}
-			Expect(decoder.configHeaders).To(Equal(cfgHeaders))
-		})
 	})
 	It("Reset", func() {
 		decoder.header.Set("a", "b")
diff --git a/components/phttp/ammo/simple/uri/provider.go b/components/phttp/ammo/simple/uri/provider.go
index 219e40f5d..a763d5c9f 100644
--- a/components/phttp/ammo/simple/uri/provider.go
+++ b/components/phttp/ammo/simple/uri/provider.go
@@ -12,20 +12,20 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
+	"go.uber.org/zap"
 )
 
 type Config struct {
 	File string
 	// Limit limits total num of ammo. Unlimited if zero.
 	Limit int `validate:"min=0"`
-	// Redefine HTTP headers
+	// Additional HTTP headers
 	Headers []string
 	// Passes limits ammo file passes. Unlimited if zero.
-	Passes int `validate:"min=0"`
-	Uris   []string
+	Passes      int `validate:"min=0"`
+	Uris        []string
+	ChosenCases []string
 }
 
 // TODO: pass logger and metricsRegistry
@@ -74,9 +74,9 @@ type Provider struct {
 }
 
 func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
-	p.decoder = newDecoder(ctx, p.Sink, &p.Pool)
+	p.decoder = newDecoder(ctx, p.Sink, &p.Pool, p.Config.ChosenCases)
 	// parse and prepare Headers from config
-	decodedConfigHeaders, err := decodeHTTPConfigHeaders(p.Config.Headers)
+	decodedConfigHeaders, err := simple.DecodeHTTPConfigHeaders(p.Config.Headers)
 	if err != nil {
 		return err
 	}
diff --git a/components/phttp/ammo/simple/uri/provider_test.go b/components/phttp/ammo/simple/uri/provider_test.go
index a0d05411b..ec2245ec3 100644
--- a/components/phttp/ammo/simple/uri/provider_test.go
+++ b/components/phttp/ammo/simple/uri/provider_test.go
@@ -9,9 +9,8 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
-	"github.com/spf13/afero"
-
 	"github.com/pkg/errors"
+	"github.com/spf13/afero"
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
 	"github.com/yandex/pandora/core"
 )
@@ -147,7 +146,6 @@ var _ = Describe("provider decode", func() {
 				"Host":       Equal(expectedData.host),
 				"URL": PointTo(MatchFields(IgnoreExtras, Fields{
 					"Scheme": BeEmpty(),
-					"Host":   Equal(expectedData.host),
 					"Path":   Equal(expectedData.path),
 				})),
 				"Header": Equal(expectedData.header),
diff --git a/components/phttp/ammo/simple/uripost/decoder.go b/components/phttp/ammo/simple/uripost/decoder.go
index 20f26f2cb..504eb0a21 100644
--- a/components/phttp/ammo/simple/uripost/decoder.go
+++ b/components/phttp/ammo/simple/uripost/decoder.go
@@ -8,11 +8,6 @@ import (
 	"github.com/pkg/errors"
 )
 
-type Header struct {
-	key   string
-	value string
-}
-
 func decodeHeader(line []byte) (key string, val string, err error) {
 	if len(line) < 3 || line[0] != '[' || line[len(line)-1] != ']' {
 		return key, val, errors.New("header line should be like '[key: value]'")
@@ -49,24 +44,3 @@ func decodeURI(uriString []byte) (bodySize int, uri string, tag string, err erro
 
 	return
 }
-
-func decodeHTTPConfigHeaders(headers []string) (configHTTPHeaders []Header, err error) {
-	for _, header := range headers {
-		line := []byte(header)
-		if len(line) < 3 || line[0] != '[' || line[len(line)-1] != ']' {
-			return nil, errors.New("header line should be like '[key: value]")
-		}
-		line = line[1 : len(line)-1]
-		colonIdx := bytes.IndexByte(line, ':')
-		if colonIdx < 0 {
-			return nil, errors.New("missing colon")
-		}
-		configHTTPHeaders = append(
-			configHTTPHeaders,
-			Header{
-				string(bytes.TrimSpace(line[:colonIdx])),
-				string(bytes.TrimSpace(line[colonIdx+1:])),
-			})
-	}
-	return
-}
diff --git a/components/phttp/ammo/simple/uripost/provider.go b/components/phttp/ammo/simple/uripost/provider.go
index 6be768a1a..28c5b8440 100644
--- a/components/phttp/ammo/simple/uripost/provider.go
+++ b/components/phttp/ammo/simple/uripost/provider.go
@@ -10,9 +10,9 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/components/phttp/ammo/simple"
+	"github.com/yandex/pandora/lib/confutil"
+	"go.uber.org/zap"
 )
 
 func filePosition(file afero.File) (position int64) {
@@ -24,10 +24,11 @@ type Config struct {
 	File string `validate:"required"`
 	// Limit limits total num of ammo. Unlimited if zero.
 	Limit int `validate:"min=0"`
-	// Redefine HTTP headers
+	// Additional HTTP headers
 	Headers []string
 	// Passes limits ammo file passes. Unlimited if zero.
-	Passes int `validate:"min=0"`
+	Passes      int `validate:"min=0"`
+	ChosenCases []string
 }
 
 func NewProvider(fs afero.Fs, conf Config) *Provider {
@@ -56,7 +57,7 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 
 	header := make(http.Header)
 	// parse and prepare Headers from config
-	decodedConfigHeaders, err := decodeHTTPConfigHeaders(p.Config.Headers)
+	decodedConfigHeaders, err := simple.DecodeHTTPConfigHeaders(p.Config.Headers)
 	if err != nil {
 		return err
 	}
@@ -91,6 +92,9 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 			if bodySize == 0 {
 				break // start over from the beginning of file if ammo size is 0
 			}
+			if !confutil.IsChosenCase(tag, p.Config.ChosenCases) {
+				continue
+			}
 			buff := make([]byte, bodySize)
 			if n, err := io.ReadFull(reader, buff); err != nil {
 				return errors.Wrapf(err, "failed to read ammo at position: %v; tried to read: %v; have read: %v", filePosition(ammoFile), bodySize, n)
@@ -104,21 +108,13 @@ func (p *Provider) start(ctx context.Context, ammoFile afero.File) error {
 				// http.Request.Write sends Host header based on req.URL.Host
 				if k == "Host" {
 					req.Host = v[0]
-					req.URL.Host = v[0]
 				} else {
 					req.Header[k] = v
 				}
 			}
 
-			// redefine request Headers from config
-			for _, header := range decodedConfigHeaders {
-				// special behavior for `Host` header
-				if header.key == "Host" {
-					req.URL.Host = header.value
-				} else {
-					req.Header.Set(header.key, header.value)
-				}
-			}
+			// add new Headers to request from config
+			simple.UpdateRequestWithHeaders(req, decodedConfigHeaders)
 
 			sh := p.Pool.Get().(*simple.Ammo)
 			sh.Reset(req, tag)
diff --git a/components/phttp/base.go b/components/phttp/base.go
index 023443fb9..985985762 100644
--- a/components/phttp/base.go
+++ b/components/phttp/base.go
@@ -16,10 +16,9 @@ import (
 	"net/url"
 
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator/netsample"
+	"go.uber.org/zap"
 )
 
 const (
diff --git a/components/phttp/base_test.go b/components/phttp/base_test.go
index d8aa9eb69..8834f9c5b 100644
--- a/components/phttp/base_test.go
+++ b/components/phttp/base_test.go
@@ -18,13 +18,12 @@ import (
 	. "github.com/onsi/ginkgo/extensions/table"
 	. "github.com/onsi/gomega"
 	"github.com/stretchr/testify/mock"
-	"go.uber.org/zap"
-
 	ammomock "github.com/yandex/pandora/components/phttp/mocks"
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator/netsample"
 	"github.com/yandex/pandora/core/coretest"
 	"github.com/yandex/pandora/lib/ginkgoutil"
+	"go.uber.org/zap"
 )
 
 func testDeps() core.GunDeps {
diff --git a/components/phttp/client.go b/components/phttp/client.go
index d8246d1e1..10502a8ee 100644
--- a/components/phttp/client.go
+++ b/components/phttp/client.go
@@ -13,11 +13,10 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-	"golang.org/x/net/http2"
-
 	"github.com/yandex/pandora/core/config"
 	"github.com/yandex/pandora/lib/netutil"
+	"go.uber.org/zap"
+	"golang.org/x/net/http2"
 )
 
 //go:generate mockery -name=Client -case=underscore -inpkg -testonly
@@ -172,3 +171,11 @@ func checkHTTP2(state *tls.ConnectionState) error {
 	}
 	return nil
 }
+
+func getHostWithoutPort(target string) string {
+	host, _, err := net.SplitHostPort(target)
+	if err != nil {
+		host = target
+	}
+	return host
+}
diff --git a/components/phttp/connect_test.go b/components/phttp/connect_test.go
index 0a0ff3c13..cf8abc521 100644
--- a/components/phttp/connect_test.go
+++ b/components/phttp/connect_test.go
@@ -15,9 +15,8 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core/aggregator/netsample"
+	"go.uber.org/zap"
 )
 
 var _ = Describe("connect", func() {
diff --git a/components/phttp/http.go b/components/phttp/http.go
index 0e8caf93c..df1451345 100644
--- a/components/phttp/http.go
+++ b/components/phttp/http.go
@@ -28,14 +28,14 @@ type HTTP2GunConfig struct {
 	Client ClientConfig    `config:",squash"`
 }
 
-func NewHTTPGun(conf HTTPGunConfig, answLog *zap.Logger) *HTTPGun {
+func NewHTTPGun(conf HTTPGunConfig, answLog *zap.Logger, targetResolved string) *HTTPGun {
 	transport := NewTransport(conf.Client.Transport, NewDialer(conf.Client.Dialer).DialContext)
 	client := newClient(transport, conf.Client.Redirect)
-	return NewClientGun(client, conf.Gun, answLog)
+	return NewClientGun(client, conf.Gun, answLog, targetResolved)
 }
 
 // NewHTTP2Gun return simple HTTP/2 gun that can shoot sequentially through one connection.
-func NewHTTP2Gun(conf HTTP2GunConfig, answLog *zap.Logger) (*HTTPGun, error) {
+func NewHTTP2Gun(conf HTTP2GunConfig, answLog *zap.Logger, targetResolved string) (*HTTPGun, error) {
 	if !conf.Gun.SSL {
 		// Open issue on github if you really need this feature.
 		return nil, errors.New("HTTP/2.0 over TCP is not supported. Please leave SSL option true by default.")
@@ -44,10 +44,10 @@ func NewHTTP2Gun(conf HTTP2GunConfig, answLog *zap.Logger) (*HTTPGun, error) {
 	client := newClient(transport, conf.Client.Redirect)
 	// Will panic and cancel shooting whet target doesn't support HTTP/2.
 	client = &panicOnHTTP1Client{client}
-	return NewClientGun(client, conf.Gun, answLog), nil
+	return NewClientGun(client, conf.Gun, answLog, targetResolved), nil
 }
 
-func NewClientGun(client Client, conf ClientGunConfig, answLog *zap.Logger) *HTTPGun {
+func NewClientGun(client Client, conf ClientGunConfig, answLog *zap.Logger, targetResolved string) *HTTPGun {
 	scheme := "http"
 	if conf.SSL {
 		scheme = "https"
@@ -63,25 +63,30 @@ func NewClientGun(client Client, conf ClientGunConfig, answLog *zap.Logger) *HTT
 			},
 			AnswLog: answLog,
 		},
-		scheme: scheme,
-		target: conf.Target,
-		client: client,
+		scheme:         scheme,
+		hostname:       getHostWithoutPort(conf.Target),
+		targetResolved: targetResolved,
+		client:         client,
 	}
 	return &g
 }
 
 type HTTPGun struct {
 	BaseGun
-	scheme string
-	target string
-	client Client
+	scheme         string
+	hostname       string
+	targetResolved string
+	client         Client
 }
 
 var _ Gun = (*HTTPGun)(nil)
 
 func (g *HTTPGun) Do(req *http.Request) (*http.Response, error) {
-	req.Host = req.URL.Host
-	req.URL.Host = g.target
+	if req.Host == "" {
+		req.Host = g.hostname
+	}
+
+	req.URL.Host = g.targetResolved
 	req.URL.Scheme = g.scheme
 	return g.client.Do(req)
 }
diff --git a/components/phttp/http_test.go b/components/phttp/http_test.go
index 7a378c979..be5cb5c7d 100644
--- a/components/phttp/http_test.go
+++ b/components/phttp/http_test.go
@@ -14,13 +14,12 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	. "github.com/onsi/gomega/gstruct"
-	"go.uber.org/atomic"
-	"go.uber.org/zap"
-	"golang.org/x/net/http2"
-
 	ammomock "github.com/yandex/pandora/components/phttp/mocks"
 	"github.com/yandex/pandora/core/aggregator/netsample"
 	"github.com/yandex/pandora/core/config"
+	"go.uber.org/atomic"
+	"go.uber.org/zap"
+	"golang.org/x/net/http2"
 )
 
 var _ = Describe("BaseGun", func() {
@@ -47,9 +46,10 @@ var _ = Describe("BaseGun", func() {
 		defer server.Close()
 		log := zap.NewNop()
 		conf := DefaultHTTPGunConfig()
-		conf.Gun.Target = strings.TrimPrefix(server.URL, "http://")
+		conf.Gun.Target = host + ":80"
+		targetResolved := strings.TrimPrefix(server.URL, "http://")
 		results := &netsample.TestAggregator{}
-		httpGun := NewHTTPGun(conf, log)
+		httpGun := NewHTTPGun(conf, log, targetResolved)
 		_ = httpGun.Bind(results, testDeps())
 
 		am := newAmmoReq(expectedReq)
@@ -59,9 +59,9 @@ var _ = Describe("BaseGun", func() {
 		Expect(*actualReq).To(MatchFields(IgnoreExtras, Fields{
 			"Method": Equal("GET"),
 			"Proto":  Equal("HTTP/1.1"),
-			"Host":   Equal(host), // Not server host, but host from ammo.
+			"Host":   Equal(host), // Server host
 			"URL": PointTo(MatchFields(IgnoreExtras, Fields{
-				"Host": BeEmpty(), // Server request.
+				"Host": BeEmpty(), // Set in Do().
 				"Path": Equal(path),
 			})),
 		}))
@@ -99,7 +99,7 @@ var _ = Describe("HTTP", func() {
 		conf := DefaultHTTPGunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
 		conf.Gun.SSL = https
-		gun := NewHTTPGun(conf, log)
+		gun := NewHTTPGun(conf, log, conf.Gun.Target)
 		var aggr netsample.TestAggregator
 		_ = gun.Bind(&aggr, testDeps())
 		gun.Shoot(newAmmoURL("/"))
@@ -125,7 +125,7 @@ var _ = Describe("HTTP", func() {
 		conf := DefaultHTTPGunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
 		conf.Client.Redirect = redirect
-		gun := NewHTTPGun(conf, log)
+		gun := NewHTTPGun(conf, log, conf.Gun.Target)
 		var aggr netsample.TestAggregator
 		_ = gun.Bind(&aggr, testDeps())
 		gun.Shoot(newAmmoURL("/redirect"))
@@ -163,7 +163,7 @@ var _ = Describe("HTTP", func() {
 		conf := DefaultHTTPGunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
 		conf.Gun.SSL = true
-		gun := NewHTTPGun(conf, log)
+		gun := NewHTTPGun(conf, log, conf.Gun.Target)
 		var results netsample.TestAggregator
 		_ = gun.Bind(&results, testDeps())
 		gun.Shoot(newAmmoURL("/"))
@@ -187,7 +187,7 @@ var _ = Describe("HTTP/2", func() {
 		log := zap.NewNop()
 		conf := DefaultHTTP2GunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
-		gun, _ := NewHTTP2Gun(conf, log)
+		gun, _ := NewHTTP2Gun(conf, log, conf.Gun.Target)
 		var results netsample.TestAggregator
 		_ = gun.Bind(&results, testDeps())
 		gun.Shoot(newAmmoURL("/"))
@@ -202,7 +202,7 @@ var _ = Describe("HTTP/2", func() {
 		log := zap.NewNop()
 		conf := DefaultHTTP2GunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
-		gun, _ := NewHTTP2Gun(conf, log)
+		gun, _ := NewHTTP2Gun(conf, log, conf.Gun.Target)
 		var results netsample.TestAggregator
 		_ = gun.Bind(&results, testDeps())
 		var r interface{}
@@ -225,7 +225,7 @@ var _ = Describe("HTTP/2", func() {
 		conf := DefaultHTTP2GunConfig()
 		conf.Gun.Target = server.Listener.Addr().String()
 		conf.Gun.SSL = false
-		_, err := NewHTTP2Gun(conf, log)
+		_, err := NewHTTP2Gun(conf, log, conf.Gun.Target)
 		Expect(err).To(HaveOccurred())
 	})
 
diff --git a/components/phttp/import/import.go b/components/phttp/import/import.go
index 9d366b612..3441b80f1 100644
--- a/components/phttp/import/import.go
+++ b/components/phttp/import/import.go
@@ -9,8 +9,6 @@ import (
 	"net"
 
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/components/phttp"
 	"github.com/yandex/pandora/components/phttp/ammo/simple/jsonline"
 	"github.com/yandex/pandora/components/phttp/ammo/simple/raw"
@@ -20,6 +18,7 @@ import (
 	"github.com/yandex/pandora/core/register"
 	"github.com/yandex/pandora/lib/answlog"
 	"github.com/yandex/pandora/lib/netutil"
+	"go.uber.org/zap"
 )
 
 func Import(fs afero.Fs) {
@@ -41,22 +40,22 @@ func Import(fs afero.Fs) {
 	})
 
 	register.Gun("http", func(conf phttp.HTTPGunConfig) func() core.Gun {
-		_ = preResolveTargetAddr(&conf.Client, &conf.Gun.Target)
+		targetResolved, _ := preResolveTargetAddr(&conf.Client, conf.Gun.Target)
 		answLog := answlog.Init(conf.Gun.Base.AnswLog.Path)
-		return func() core.Gun { return phttp.WrapGun(phttp.NewHTTPGun(conf, answLog)) }
+		return func() core.Gun { return phttp.WrapGun(phttp.NewHTTPGun(conf, answLog, targetResolved)) }
 	}, phttp.DefaultHTTPGunConfig)
 
 	register.Gun("http2", func(conf phttp.HTTP2GunConfig) func() (core.Gun, error) {
-		_ = preResolveTargetAddr(&conf.Client, &conf.Gun.Target)
+		targetResolved, _ := preResolveTargetAddr(&conf.Client, conf.Gun.Target)
 		answLog := answlog.Init(conf.Gun.Base.AnswLog.Path)
 		return func() (core.Gun, error) {
-			gun, err := phttp.NewHTTP2Gun(conf, answLog)
+			gun, err := phttp.NewHTTP2Gun(conf, answLog, targetResolved)
 			return phttp.WrapGun(gun), err
 		}
 	}, phttp.DefaultHTTP2GunConfig)
 
 	register.Gun("connect", func(conf phttp.ConnectGunConfig) func() core.Gun {
-		_ = preResolveTargetAddr(&conf.Client, &conf.Target)
+		conf.Target, _ = preResolveTargetAddr(&conf.Client, conf.Target)
 		answLog := answlog.Init(conf.BaseGunConfig.AnswLog.Path)
 		return func() core.Gun {
 			return phttp.WrapGun(phttp.NewConnectGun(conf, answLog))
@@ -70,22 +69,24 @@ func Import(fs afero.Fs) {
 // If we can resolve accessible target addr - use it as target, not use caching.
 // Otherwise just use DNS cache - we should not fail shooting, we should try to
 // connect on every shoot. DNS cache will save resolved addr after first successful connect.
-func preResolveTargetAddr(clientConf *phttp.ClientConfig, target *string) (err error) {
+func preResolveTargetAddr(clientConf *phttp.ClientConfig, target string) (targetAddr string, err error) {
+	targetAddr = target
+
 	if !clientConf.Dialer.DNSCache {
 		return
 	}
-	if endpointIsResolved(*target) {
+	if endpointIsResolved(target) {
 		clientConf.Dialer.DNSCache = false
 		return
 	}
-	resolved, err := netutil.LookupReachable(*target)
+	resolved, err := netutil.LookupReachable(target, clientConf.Dialer.Timeout)
 	if err != nil {
 		zap.L().Warn("DNS target pre resolve failed",
-			zap.String("target", *target), zap.Error(err))
+			zap.String("target", target), zap.Error(err))
 		return
 	}
 	clientConf.Dialer.DNSCache = false
-	*target = resolved
+	targetAddr = resolved
 	return
 }
 
diff --git a/components/phttp/import/import_suite_test.go b/components/phttp/import/import_suite_test.go
index 6b4f5bc49..fd427c25a 100644
--- a/components/phttp/import/import_suite_test.go
+++ b/components/phttp/import/import_suite_test.go
@@ -8,7 +8,6 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/spf13/afero"
-
 	. "github.com/yandex/pandora/components/phttp"
 	"github.com/yandex/pandora/lib/ginkgoutil"
 )
@@ -40,7 +39,7 @@ var _ = Describe("preResolveTargetAddr", func() {
 		target := "localhost:" + port
 		expectedResolved := "127.0.0.1:" + port
 
-		err = preResolveTargetAddr(conf, &target)
+		target, err = preResolveTargetAddr(conf, target)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(conf.Dialer.DNSCache).To(BeFalse())
 
@@ -53,7 +52,7 @@ var _ = Describe("preResolveTargetAddr", func() {
 
 		const addr = "127.0.0.1:80"
 		target := addr
-		err := preResolveTargetAddr(conf, &target)
+		target, err := preResolveTargetAddr(conf, target)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(conf.Dialer.DNSCache).To(BeFalse())
 		Expect(target).To(Equal(addr))
@@ -65,7 +64,7 @@ var _ = Describe("preResolveTargetAddr", func() {
 
 		const addr = "localhost:54321"
 		target := addr
-		err := preResolveTargetAddr(conf, &target)
+		target, err := preResolveTargetAddr(conf, target)
 		Expect(err).To(HaveOccurred())
 		Expect(conf.Dialer.DNSCache).To(BeTrue())
 		Expect(target).To(Equal(addr))
diff --git a/core/aggregator/encoder.go b/core/aggregator/encoder.go
index 8faf680e8..a13ae9df4 100644
--- a/core/aggregator/encoder.go
+++ b/core/aggregator/encoder.go
@@ -11,7 +11,6 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coreutil"
 	"github.com/yandex/pandora/lib/errutil"
diff --git a/core/aggregator/encoder_test.go b/core/aggregator/encoder_test.go
index ad8a3aadf..302f2df6a 100644
--- a/core/aggregator/encoder_test.go
+++ b/core/aggregator/encoder_test.go
@@ -17,13 +17,12 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	aggregatemock "github.com/yandex/pandora/core/aggregator/mocks"
 	coremock "github.com/yandex/pandora/core/mocks"
 	iomock "github.com/yandex/pandora/lib/ioutil2/mocks"
 	"github.com/yandex/pandora/lib/testutil"
+	"go.uber.org/zap"
 )
 
 type EncoderAggregatorTester struct {
diff --git a/core/aggregator/jsonlines.go b/core/aggregator/jsonlines.go
index 065a721cd..2d19b9067 100644
--- a/core/aggregator/jsonlines.go
+++ b/core/aggregator/jsonlines.go
@@ -10,11 +10,10 @@ import (
 	"io"
 
 	jsoniter "github.com/json-iterator/go"
-	"github.com/yandex/pandora/lib/ioutil2"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/config"
 	"github.com/yandex/pandora/core/coreutil"
+	"github.com/yandex/pandora/lib/ioutil2"
 )
 
 type JSONLineAggregatorConfig struct {
diff --git a/core/aggregator/jsonlines_test.go b/core/aggregator/jsonlines_test.go
index 3c2549f5d..0ca60fbf9 100644
--- a/core/aggregator/jsonlines_test.go
+++ b/core/aggregator/jsonlines_test.go
@@ -12,10 +12,9 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/datasink"
+	"go.uber.org/zap"
 )
 
 type jsonTestData struct {
diff --git a/core/aggregator/log.go b/core/aggregator/log.go
index cf40e5ca3..681dca3ee 100644
--- a/core/aggregator/log.go
+++ b/core/aggregator/log.go
@@ -8,9 +8,8 @@ package aggregator
 import (
 	"context"
 
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
+	"go.uber.org/zap"
 )
 
 func NewLog() core.Aggregator {
diff --git a/core/aggregator/mocks/sample_encode_closer.go b/core/aggregator/mocks/sample_encode_closer.go
index 5e152cc15..0e409af97 100644
--- a/core/aggregator/mocks/sample_encode_closer.go
+++ b/core/aggregator/mocks/sample_encode_closer.go
@@ -3,7 +3,6 @@ package aggregatemock
 
 import (
 	mock "github.com/stretchr/testify/mock"
-
 	core "github.com/yandex/pandora/core"
 )
 
diff --git a/core/aggregator/netsample/phout.go b/core/aggregator/netsample/phout.go
index 7a770982c..a72733cf6 100644
--- a/core/aggregator/netsample/phout.go
+++ b/core/aggregator/netsample/phout.go
@@ -11,7 +11,6 @@ import (
 	"github.com/c2h5oh/datasize"
 	"github.com/pkg/errors"
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coreutil"
 )
diff --git a/core/aggregator/netsample/phout_test.go b/core/aggregator/netsample/phout_test.go
index 95e734758..33f6a7bea 100644
--- a/core/aggregator/netsample/phout_test.go
+++ b/core/aggregator/netsample/phout_test.go
@@ -8,7 +8,6 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/aggregator/netsample/sample.go b/core/aggregator/netsample/sample.go
index 90d790612..af76ae4c8 100644
--- a/core/aggregator/netsample/sample.go
+++ b/core/aggregator/netsample/sample.go
@@ -7,6 +7,7 @@ package netsample
 
 import (
 	"net"
+	"net/url"
 	"os"
 	"sync"
 	"syscall"
@@ -16,7 +17,9 @@ import (
 )
 
 const (
-	ProtoCodeError = 999
+	ProtoCodeError          = 999
+	DiscardedShootCodeError = 777
+	DiscardedShootTag       = "discarded"
 )
 
 const (
@@ -117,6 +120,10 @@ func (s *Sample) String() string {
 }
 
 func getErrno(err error) int {
+	//
+	if e, ok := err.(net.Error); ok && e.Timeout() {
+		return 110 // Handle client Timeout as if it connection timeout
+	}
 	// stackerr.Error and etc.
 	type hasUnderlying interface {
 		Underlying() error
@@ -135,6 +142,8 @@ func getErrno(err error) int {
 			err = typed.Err
 		case *os.SyscallError:
 			err = typed.Err
+		case *url.Error:
+			err = typed.Err
 		case syscall.Errno:
 			return int(typed)
 		default:
@@ -143,3 +152,13 @@ func getErrno(err error) int {
 		}
 	}
 }
+
+func DiscardedShootSample() *Sample {
+	sample := &Sample{
+		timeStamp: time.Now(),
+		tags:      DiscardedShootTag,
+	}
+	sample.SetUserNet(DiscardedShootCodeError)
+
+	return sample
+}
diff --git a/core/aggregator/netsample/sample_test.go b/core/aggregator/netsample/sample_test.go
index b084a510b..d8f302c8e 100644
--- a/core/aggregator/netsample/sample_test.go
+++ b/core/aggregator/netsample/sample_test.go
@@ -79,8 +79,8 @@ func TestCustomSets(t *testing.T) {
 		tag,
 		int(userDuration.Nanoseconds()/1000), // keyRTTMicro
 		int(latency.Nanoseconds()/1000),      // keyLatencyMicro
-		reqBytes,  // keyRequestBytes
-		respBytes, // keyResponseBytes
+		reqBytes,                             // keyRequestBytes
+		respBytes,                            // keyResponseBytes
 		110,
 		0,
 	)
diff --git a/core/aggregator/reporter.go b/core/aggregator/reporter.go
index 5a3cfed1b..c7809e897 100644
--- a/core/aggregator/reporter.go
+++ b/core/aggregator/reporter.go
@@ -8,11 +8,10 @@ package aggregator
 import (
 	"fmt"
 
-	"go.uber.org/atomic"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coreutil"
+	"go.uber.org/atomic"
+	"go.uber.org/zap"
 )
 
 type ReporterConfig struct {
diff --git a/core/aggregator/reporter_test.go b/core/aggregator/reporter_test.go
index 880ee14da..a1f950fec 100644
--- a/core/aggregator/reporter_test.go
+++ b/core/aggregator/reporter_test.go
@@ -10,11 +10,10 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"go.uber.org/zap"
-	"go.uber.org/zap/zaptest/observer"
-
 	coremock "github.com/yandex/pandora/core/mocks"
 	"github.com/yandex/pandora/lib/testutil"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zaptest/observer"
 )
 
 func TestReporter_DroppedErr(t *testing.T) {
diff --git a/core/config/config.go b/core/config/config.go
index 429cbbaf8..5652abc91 100644
--- a/core/config/config.go
+++ b/core/config/config.go
@@ -84,6 +84,7 @@ func AddKindHook(hook KindHook) (_ struct{}) {
 
 func DefaultHooks() []mapstructure.DecodeHookFunc {
 	return []mapstructure.DecodeHookFunc{
+		VariableInjectHook,
 		DebugHook,
 		TextUnmarshallerHook,
 		mapstructure.StringToTimeDurationHookFunc(),
diff --git a/core/config/config_test.go b/core/config/config_test.go
index a602c6bc1..33086e662 100644
--- a/core/config/config_test.go
+++ b/core/config/config_test.go
@@ -6,12 +6,14 @@
 package config
 
 import (
+	"net"
 	"testing"
 	"time"
 
 	"github.com/facebookgo/stack"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"github.com/yandex/pandora/lib/confutil"
 )
 
 type M map[string]interface{}
@@ -231,3 +233,31 @@ func TestNextSquash(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "baz", data.Level1.Level2.Foo)
 }
+
+func TestConfigEnvVarReplacement(t *testing.T) {
+	confutil.RegisterTagResolver("", confutil.EnvTagResolver)
+	confutil.RegisterTagResolver("ENV", confutil.EnvTagResolver)
+
+	t.Setenv("ENV_VAR_1", "value1")
+	t.Setenv("VAR_2", "value2")
+	t.Setenv("INT_VAR_3", "15")
+	t.Setenv("IP_SEQ", "1.2")
+	var l1 struct {
+		Val1 string
+		Val2 string
+		Val3 int
+		Val4 net.IP
+	}
+
+	err := Decode(M{
+		"val1": "aa-${ENV_VAR_1}",
+		"val2": "${ENV:VAR_2}",
+		"val3": "${INT_VAR_3}",
+		"val4": "1.1.${ENV:IP_SEQ}",
+	}, &l1)
+	assert.NoError(t, err)
+	assert.Equal(t, "aa-value1", l1.Val1)
+	assert.Equal(t, "value2", l1.Val2)
+	assert.Equal(t, 15, l1.Val3)
+	assert.Equal(t, net.IPv4(1, 1, 1, 2), l1.Val4)
+}
diff --git a/core/config/hooks.go b/core/config/hooks.go
index 2b4df157a..0fe69096b 100644
--- a/core/config/hooks.go
+++ b/core/config/hooks.go
@@ -17,9 +17,9 @@ import (
 	"github.com/c2h5oh/datasize"
 	"github.com/facebookgo/stack"
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
+	"github.com/yandex/pandora/lib/confutil"
 	"github.com/yandex/pandora/lib/tag"
+	"go.uber.org/zap"
 )
 
 var InvalidURLError = errors.New("string is not valid URL")
@@ -138,3 +138,22 @@ func DebugHook(f reflect.Type, t reflect.Type, data interface{}) (p interface{},
 	)
 	return
 }
+
+// VariableInjectHook injects values into ${VAR_NAME} placeholders
+func VariableInjectHook(f reflect.Type, t reflect.Type, data interface{}) (interface{}, error) {
+	if f.Kind() != reflect.String {
+		return data, nil
+	}
+
+	str := data.(string)
+	res, err := confutil.ResolveCustomTags(str, t)
+	if err == confutil.ErrNoTagsFound {
+		return data, nil
+	}
+
+	if err != nil {
+		return data, err
+	}
+
+	return res, nil
+}
diff --git a/core/coretest/sink.go b/core/coretest/sink.go
index d54c33167..191c44111 100644
--- a/core/coretest/sink.go
+++ b/core/coretest/sink.go
@@ -14,7 +14,6 @@ import (
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/coretest/source.go b/core/coretest/source.go
index ae5ac8f4c..9aa94bdb7 100644
--- a/core/coretest/source.go
+++ b/core/coretest/source.go
@@ -14,7 +14,6 @@ import (
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/lib/testutil"
 )
diff --git a/core/coreutil/buffer_size_config_test.go b/core/coreutil/buffer_size_config_test.go
index 13223be73..aeb8fbd13 100644
--- a/core/coreutil/buffer_size_config_test.go
+++ b/core/coreutil/buffer_size_config_test.go
@@ -9,7 +9,7 @@ import (
 	"testing"
 
 	"github.com/c2h5oh/datasize"
-	"github.com/magiconair/properties/assert"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestBufferSizeConfig_BufferSizeOrDefault(t *testing.T) {
diff --git a/core/coreutil/schedule_test.go b/core/coreutil/schedule_test.go
index 93d84f3c5..a4a3613b1 100644
--- a/core/coreutil/schedule_test.go
+++ b/core/coreutil/schedule_test.go
@@ -10,7 +10,6 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
 	"github.com/yandex/pandora/core/schedule"
 )
 
diff --git a/core/coreutil/waiter.go b/core/coreutil/waiter.go
index 06cd1c3fb..88d3ce3dc 100644
--- a/core/coreutil/waiter.go
+++ b/core/coreutil/waiter.go
@@ -14,8 +14,9 @@ import (
 
 // Waiter goroutine unsafe wrapper for efficient waiting schedule.
 type Waiter struct {
-	sched core.Schedule
-	ctx   context.Context
+	sched         core.Schedule
+	ctx           context.Context
+	slowDownItems int
 
 	// Lazy initialized.
 	timer   *time.Timer
@@ -33,23 +34,28 @@ func (w *Waiter) Wait() (ok bool) {
 	// Check, that context is not done. Very quick: 5 ns for op, due to benchmark.
 	select {
 	case <-w.ctx.Done():
+		w.slowDownItems = 0
 		return false
 	default:
 	}
 	next, ok := w.sched.Next()
 	if !ok {
+		w.slowDownItems = 0
 		return false
 	}
 	// Get current time lazily.
 	// For once schedule, for example, we need to get it only once.
 	if next.Before(w.lastNow) {
+		w.slowDownItems++
 		return true
 	}
 	w.lastNow = time.Now()
 	waitFor := next.Sub(w.lastNow)
 	if waitFor <= 0 {
+		w.slowDownItems++
 		return true
 	}
+	w.slowDownItems = 0
 	// Lazy init. We don't need timer for unlimited and once schedule.
 	if w.timer == nil {
 		w.timer = time.NewTimer(waitFor)
@@ -64,6 +70,16 @@ func (w *Waiter) Wait() (ok bool) {
 	}
 }
 
+// IsSlowDown returns true, if schedule contains 2 elements before current time.
+func (w *Waiter) IsSlowDown() (ok bool) {
+	select {
+	case <-w.ctx.Done():
+		return false
+	default:
+		return w.slowDownItems >= 2
+	}
+}
+
 // IsFinished is quick check, that wait context is not canceled and there are some tokens left in
 // schedule.
 func (w *Waiter) IsFinished() (ok bool) {
diff --git a/core/coreutil/waiter_test.go b/core/coreutil/waiter_test.go
index 4cb0309e8..d5629ecc2 100644
--- a/core/coreutil/waiter_test.go
+++ b/core/coreutil/waiter_test.go
@@ -11,7 +11,6 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
 	"github.com/yandex/pandora/core/schedule"
 )
 
diff --git a/core/datasink/file.go b/core/datasink/file.go
index 48189f707..610cff137 100644
--- a/core/datasink/file.go
+++ b/core/datasink/file.go
@@ -10,7 +10,6 @@ import (
 	"os"
 
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/datasink/file_test.go b/core/datasink/file_test.go
index 018ba9720..df6ef0dd9 100644
--- a/core/datasink/file_test.go
+++ b/core/datasink/file_test.go
@@ -10,7 +10,6 @@ import (
 	"testing"
 
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/core/coretest"
 )
 
diff --git a/core/datasource/file.go b/core/datasource/file.go
index 0ebb346ef..f5a885521 100644
--- a/core/datasource/file.go
+++ b/core/datasource/file.go
@@ -10,7 +10,6 @@ import (
 	"os"
 
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/engine/engine.go b/core/engine/engine.go
index 957b5c749..a5ac5ed6e 100644
--- a/core/engine/engine.go
+++ b/core/engine/engine.go
@@ -10,15 +10,13 @@ import (
 	"fmt"
 	"sync"
 
-	"github.com/yandex/pandora/core/warmup"
-
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coreutil"
+	"github.com/yandex/pandora/core/warmup"
 	"github.com/yandex/pandora/lib/errutil"
 	"github.com/yandex/pandora/lib/monitoring"
+	"go.uber.org/zap"
 )
 
 type Config struct {
@@ -33,6 +31,7 @@ type InstancePoolConfig struct {
 	RPSPerInstance  bool                          `config:"rps-per-instance"`
 	NewRPSSchedule  func() (core.Schedule, error) `config:"rps" validate:"required"`
 	StartupSchedule core.Schedule                 `config:"startup" validate:"required"`
+	DiscardOverflow bool                          `config:"discard_overflow"`
 }
 
 // TODO(skipor): use something github.com/rcrowley/go-metrics based.
@@ -364,10 +363,9 @@ func (p *instancePool) startInstances(
 	newInstanceSchedule func() (core.Schedule, error),
 	runRes chan<- instanceRunResult) (started int, err error) {
 	deps := instanceDeps{
-		p.Aggregator,
 		newInstanceSchedule,
 		p.NewGun,
-		instanceSharedDeps{p.Provider, p.metrics, p.gunWarmUpResult},
+		instanceSharedDeps{p.Provider, p.metrics, p.gunWarmUpResult, p.Aggregator, p.DiscardOverflow},
 	}
 
 	waiter := coreutil.NewWaiter(p.StartupSchedule, startCtx)
diff --git a/core/engine/engine_test.go b/core/engine/engine_test.go
index 062018a27..5729b7456 100644
--- a/core/engine/engine_test.go
+++ b/core/engine/engine_test.go
@@ -9,8 +9,6 @@ import (
 	. "github.com/onsi/gomega"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/mock"
-	"go.uber.org/atomic"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator"
 	"github.com/yandex/pandora/core/config"
@@ -18,6 +16,7 @@ import (
 	"github.com/yandex/pandora/core/provider"
 	"github.com/yandex/pandora/core/schedule"
 	"github.com/yandex/pandora/lib/ginkgoutil"
+	"go.uber.org/atomic"
 )
 
 var _ = Describe("config validation", func() {
diff --git a/core/engine/instance.go b/core/engine/instance.go
index 42f8c882b..fdcd0b6a1 100644
--- a/core/engine/instance.go
+++ b/core/engine/instance.go
@@ -10,14 +10,13 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/yandex/pandora/core/warmup"
-
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
+	"github.com/yandex/pandora/core/aggregator/netsample"
 	"github.com/yandex/pandora/core/coreutil"
+	"github.com/yandex/pandora/core/warmup"
 	"github.com/yandex/pandora/lib/tag"
+	"go.uber.org/zap"
 )
 
 type instance struct {
@@ -53,7 +52,6 @@ func newInstance(ctx context.Context, log *zap.Logger, poolID string, id int, de
 }
 
 type instanceDeps struct {
-	aggregator  core.Aggregator
 	newSchedule func() (core.Schedule, error)
 	newGun      func() (core.Gun, error)
 	instanceSharedDeps
@@ -63,6 +61,8 @@ type instanceSharedDeps struct {
 	provider core.Provider
 	Metrics
 	gunWarmUpResult interface{}
+	aggregator      core.Aggregator
+	discardOverflow bool
 }
 
 // Run blocks until ammo finish, error or context cancel.
@@ -90,24 +90,34 @@ func (i *instance) shoot(ctx context.Context) (err error) {
 	// Checking, that schedule is not finished, required, to not consume extra ammo,
 	// on finish in case of per instance schedule.
 	for !waiter.IsFinished() {
-		ammo, ok := i.provider.Acquire()
-		if !ok {
-			i.log.Debug("Out of ammo")
-			return outOfAmmoErr
-		}
-		if tag.Debug {
-			i.log.Debug("Ammo acquired", zap.Any("ammo", ammo))
-		}
-		if !waiter.Wait() {
-			break
-		}
-		i.Metrics.Request.Add(1)
-		if tag.Debug {
-			i.log.Debug("Shooting", zap.Any("ammo", ammo))
+		err := func() error {
+			ammo, ok := i.provider.Acquire()
+			if !ok {
+				i.log.Debug("Out of ammo")
+				return outOfAmmoErr
+			}
+			defer i.provider.Release(ammo)
+			if tag.Debug {
+				i.log.Debug("Ammo acquired", zap.Any("ammo", ammo))
+			}
+			if !waiter.Wait() {
+				return nil
+			}
+			if !i.discardOverflow || !waiter.IsSlowDown() {
+				i.Metrics.Request.Add(1)
+				if tag.Debug {
+					i.log.Debug("Shooting", zap.Any("ammo", ammo))
+				}
+				i.gun.Shoot(ammo)
+				i.Metrics.Response.Add(1)
+			} else {
+				i.aggregator.Report(netsample.DiscardedShootSample())
+			}
+			return nil
+		}()
+		if err != nil {
+			return err
 		}
-		i.gun.Shoot(ammo)
-		i.Metrics.Response.Add(1)
-		i.provider.Release(ammo)
 	}
 	return ctx.Err()
 }
diff --git a/core/engine/instance_test.go b/core/engine/instance_test.go
index e64d8fbf3..029d93aa6 100644
--- a/core/engine/instance_test.go
+++ b/core/engine/instance_test.go
@@ -8,7 +8,6 @@ import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 	"github.com/stretchr/testify/mock"
-
 	"github.com/yandex/pandora/core"
 	coremock "github.com/yandex/pandora/core/mocks"
 	"github.com/yandex/pandora/core/schedule"
@@ -48,13 +47,15 @@ var _ = Describe("Instance", func() {
 
 	JustBeforeEach(func() {
 		deps := instanceDeps{
-			aggregator,
+
 			newSchedule,
 			newGun,
 			instanceSharedDeps{
 				provider,
 				metrics,
 				nil,
+				aggregator,
+				false,
 			},
 		}
 		ins, insCreateErr = newInstance(ctx, ginkgoutil.NewLogger(), "pool_0", 0, deps)
diff --git a/core/import/import.go b/core/import/import.go
index cbf1a440c..6d436094a 100644
--- a/core/import/import.go
+++ b/core/import/import.go
@@ -9,8 +9,6 @@ import (
 	"reflect"
 
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/aggregator"
 	"github.com/yandex/pandora/core/aggregator/netsample"
@@ -22,7 +20,9 @@ import (
 	"github.com/yandex/pandora/core/provider"
 	"github.com/yandex/pandora/core/register"
 	"github.com/yandex/pandora/core/schedule"
+	"github.com/yandex/pandora/lib/confutil"
 	"github.com/yandex/pandora/lib/tag"
+	"go.uber.org/zap"
 )
 
 const (
@@ -88,11 +88,15 @@ func Import(fs afero.Fs) {
 	register.Limiter("once", schedule.NewOnceConf)
 	register.Limiter("unlimited", schedule.NewUnlimitedConf)
 	register.Limiter("step", schedule.NewStepConf)
+	register.Limiter("instance_step", schedule.NewInstanceStepConf)
 	register.Limiter(compositeScheduleKey, schedule.NewCompositeConf)
 
 	config.AddTypeHook(sinkStringHook)
 	config.AddTypeHook(scheduleSliceToCompositeConfigHook)
 
+	confutil.RegisterTagResolver("", confutil.EnvTagResolver)
+	confutil.RegisterTagResolver("ENV", confutil.EnvTagResolver)
+
 	// Required for decoding plugins. Need to be added after Composite Schedule hacky hook.
 	pluginconfig.AddHooks()
 }
diff --git a/core/import/import_suite_test.go b/core/import/import_suite_test.go
index 2d296839c..a83785439 100644
--- a/core/import/import_suite_test.go
+++ b/core/import/import_suite_test.go
@@ -10,14 +10,13 @@ import (
 	. "github.com/onsi/gomega"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/config"
 	"github.com/yandex/pandora/core/coretest"
 	"github.com/yandex/pandora/core/plugin"
 	"github.com/yandex/pandora/lib/ginkgoutil"
 	"github.com/yandex/pandora/lib/testutil"
+	"go.uber.org/zap"
 )
 
 func TestImport(t *testing.T) {
diff --git a/core/plugin/pluginconfig/hooks.go b/core/plugin/pluginconfig/hooks.go
index fe669bb49..4c3e44106 100644
--- a/core/plugin/pluginconfig/hooks.go
+++ b/core/plugin/pluginconfig/hooks.go
@@ -14,11 +14,10 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core/config"
 	"github.com/yandex/pandora/core/plugin"
 	"github.com/yandex/pandora/lib/tag"
+	"go.uber.org/zap"
 )
 
 func AddHooks() {
diff --git a/core/plugin/ptest_test.go b/core/plugin/ptest_test.go
index cfae16f84..69850d285 100644
--- a/core/plugin/ptest_test.go
+++ b/core/plugin/ptest_test.go
@@ -10,7 +10,6 @@ import (
 
 	. "github.com/onsi/gomega"
 	"github.com/pkg/errors"
-
 	"github.com/yandex/pandora/core/config"
 )
 
diff --git a/core/provider/chunk_decoder.go b/core/provider/chunk_decoder.go
index 0904b4497..2fd851ca7 100644
--- a/core/provider/chunk_decoder.go
+++ b/core/provider/chunk_decoder.go
@@ -10,7 +10,6 @@ import (
 	"fmt"
 
 	"github.com/pkg/errors"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/provider/decoder.go b/core/provider/decoder.go
index 99beede72..01a923c38 100644
--- a/core/provider/decoder.go
+++ b/core/provider/decoder.go
@@ -11,11 +11,10 @@ import (
 	"io"
 
 	"github.com/pkg/errors"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/lib/errutil"
 	"github.com/yandex/pandora/lib/ioutil2"
+	"go.uber.org/zap"
 )
 
 type NewAmmoDecoder func(deps core.ProviderDeps, source io.Reader) (AmmoDecoder, error)
diff --git a/core/provider/json.go b/core/provider/json.go
index 586935c58..820a991f0 100644
--- a/core/provider/json.go
+++ b/core/provider/json.go
@@ -9,7 +9,6 @@ import (
 	"io"
 
 	jsoniter "github.com/json-iterator/go"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coreutil"
 	"github.com/yandex/pandora/lib/ioutil2"
diff --git a/core/provider/json_test.go b/core/provider/json_test.go
index 1bb44f222..1690d0086 100644
--- a/core/provider/json_test.go
+++ b/core/provider/json_test.go
@@ -13,7 +13,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/datasource"
 )
diff --git a/core/provider/num_test.go b/core/provider/num_test.go
index a7722cb67..caf7242f6 100644
--- a/core/provider/num_test.go
+++ b/core/provider/num_test.go
@@ -5,7 +5,6 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
 	"github.com/yandex/pandora/core"
 )
 
diff --git a/core/schedule/composite_test.go b/core/schedule/composite_test.go
index e4e0dc86c..67c053837 100644
--- a/core/schedule/composite_test.go
+++ b/core/schedule/composite_test.go
@@ -11,7 +11,6 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coretest"
 	"go.uber.org/atomic"
diff --git a/core/schedule/do_at.go b/core/schedule/do_at.go
index e33b8ae23..dddcaf696 100644
--- a/core/schedule/do_at.go
+++ b/core/schedule/do_at.go
@@ -8,9 +8,8 @@ package schedule
 import (
 	"time"
 
-	"go.uber.org/atomic"
-
 	"github.com/yandex/pandora/core"
+	"go.uber.org/atomic"
 )
 
 // DoAt returns when i'th operation should be performed, assuming that schedule
diff --git a/core/schedule/instance_step.go b/core/schedule/instance_step.go
new file mode 100644
index 000000000..9724854ef
--- /dev/null
+++ b/core/schedule/instance_step.go
@@ -0,0 +1,35 @@
+// Copyright (c) 2017 Yandex LLC. All rights reserved.
+// Use of this source code is governed by a MPL 2.0
+// license that can be found in the LICENSE file.
+// Author: Vladimir Skipor <skipor@yandex-team.ru>
+
+package schedule
+
+import (
+	"time"
+
+	"github.com/yandex/pandora/core"
+)
+
+func NewInstanceStep(from, to int64, step int64, stepDuration time.Duration) core.Schedule {
+	var nexts []core.Schedule
+	nexts = append(nexts, NewOnce(from))
+
+	for i := from + step; i <= to; i += step {
+		nexts = append(nexts, NewConst(0, stepDuration))
+		nexts = append(nexts, NewOnce(step))
+	}
+
+	return NewCompositeConf(CompositeConf{nexts})
+}
+
+type InstanceStepConfig struct {
+	From         int64         `validate:"min=0"`
+	To           int64         `validate:"min=0"`
+	Step         int64         `validate:"min=1"`
+	StepDuration time.Duration `validate:"min-time=1ms"`
+}
+
+func NewInstanceStepConf(conf InstanceStepConfig) core.Schedule {
+	return NewInstanceStep(conf.From, conf.To, conf.Step, conf.StepDuration)
+}
diff --git a/core/schedule/schedule_suite_test.go b/core/schedule/schedule_suite_test.go
index b63469a7a..aea7fe558 100644
--- a/core/schedule/schedule_suite_test.go
+++ b/core/schedule/schedule_suite_test.go
@@ -7,7 +7,6 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
 	"github.com/yandex/pandora/core"
 	"github.com/yandex/pandora/core/coretest"
 	"github.com/yandex/pandora/lib/ginkgoutil"
@@ -207,6 +206,21 @@ var _ = Describe("step", func() {
 
 })
 
+var _ = Describe("instance_step", func() {
+	It("", func() {
+		conf := InstanceStepConfig{
+			From:         1,
+			To:           3,
+			Step:         1,
+			StepDuration: 2 * time.Second,
+		}
+		testee := NewInstanceStepConf(conf)
+		Expect(testee.Left()).To(Equal(3))
+
+	})
+
+})
+
 func BenchmarkLineSchedule(b *testing.B) {
 	schedule := NewLine(0, float64(b.N), 2*time.Second)
 	benchmarkScheduleNext(b, schedule)
diff --git a/core/schedule/start_sync.go b/core/schedule/start_sync.go
index 4b2b5215f..43f35682b 100644
--- a/core/schedule/start_sync.go
+++ b/core/schedule/start_sync.go
@@ -6,9 +6,9 @@
 package schedule
 
 import (
-	"go.uber.org/atomic"
-
 	"sync"
+
+	"go.uber.org/atomic"
 )
 
 // StartSync is util to make schedule start goroutine safe.
diff --git a/docs/advanced.rst b/docs/advanced.rst
index 03d2d0a52..25e843242 100644
--- a/docs/advanced.rst
+++ b/docs/advanced.rst
@@ -18,7 +18,7 @@ Pay attention to special header `Host` defined ``outside`` of Headers dictionary
 Ammofile sample:
 ::
 
-  {"uri": "/", "method": "GET", "headers": {"Accept": "*/*", "Accept-Encoding": "gzip, deflate", "User-Agent": "Pandora"}, "host": "example.com"}
+  {"tag": "tag1", "uri": "/", "method": "GET", "headers": {"Accept": "*/*", "Accept-Encoding": "gzip, deflate", "User-Agent": "Pandora"}, "host": "example.com"}
 
 Config sample:
 
@@ -70,7 +70,7 @@ Config sample:
         type: raw                      # ammo format
         file: ./ammofile               # ammo file path
 
-You can redefine any headers using special config option `headers`. Format: list of strings.
+You can define common headers using special config option `headers`. Headers in ammo file have priority. Format: list of strings.
 
 Example:
 
@@ -111,7 +111,7 @@ Config sample:
         file: ./ammofile               # ammo file path
 
 
-You can redefine any headers using special config option `headers`. Format: list of strings.
+You can define common headers using special config option `headers`. Headers in ammo file have priority. Format: list of strings.
 
 Example:
 
@@ -124,3 +124,32 @@ Example:
         headers:
           - "[Host: yourhost.tld]"
           - "[User-Agent: some user agent]"
+
+Ammo filters
+------------
+
+Each http ammo provider lets you choose specific ammo for your test from ammo file with `chosencases` setting:
+.. code-block:: yaml
+
+  pools:
+    - ammo:
+        type: uri                      # ammo format
+        chosencases: ["tag1", "tag2"]  # use only "tag1" and "tag2" ammo for this test
+        file: ./ammofile               # ammo file path
+
+Tags are defined in ammo files as shown below:
+
+http/json:
+::
+  {"tag": "tag1", "uri": "/",
+
+raw (request-style):
+::
+  73 tag1
+  GET / HTTP/1.0
+
+uri-style:
+::
+  /?drg tag1
+  /
+  /buy tag2
\ No newline at end of file
diff --git a/examples/custom_pandora/custom_main.go b/examples/custom_pandora/custom_main.go
index b5304501d..c25569f85 100644
--- a/examples/custom_pandora/custom_main.go
+++ b/examples/custom_pandora/custom_main.go
@@ -10,13 +10,12 @@ import (
 	"time"
 
 	"github.com/spf13/afero"
-	"go.uber.org/zap"
-
 	"github.com/yandex/pandora/cli"
 	phttp "github.com/yandex/pandora/components/phttp/import"
 	"github.com/yandex/pandora/core"
 	coreimport "github.com/yandex/pandora/core/import"
 	"github.com/yandex/pandora/core/register"
+	"go.uber.org/zap"
 )
 
 type Ammo struct {
diff --git a/go.mod b/go.mod
index 565b6cadc..89c3b8493 100644
--- a/go.mod
+++ b/go.mod
@@ -12,7 +12,6 @@ require (
 	github.com/hashicorp/go-multierror v0.0.0-20171204182908-b7773ae21874
 	github.com/jhump/protoreflect v1.10.1
 	github.com/json-iterator/go v0.0.0-20180214060632-e7c7f3b33712
-	github.com/magiconair/properties v1.7.6
 	github.com/mitchellh/mapstructure v0.0.0-20180203102830-a4e142e9c047
 	github.com/onsi/ginkgo v1.4.0
 	github.com/onsi/gomega v1.3.0
diff --git a/go.sum b/go.sum
index 53cccadaa..f9b39fb6e 100644
--- a/go.sum
+++ b/go.sum
@@ -75,8 +75,6 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/magiconair/properties v1.7.6 h1:U+1DqNen04MdEPgFiIwdOUiqZ8qPa37xgogX/sd3+54=
-github.com/magiconair/properties v1.7.6/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mitchellh/mapstructure v0.0.0-20180203102830-a4e142e9c047 h1:zCoDWFD5nrJJVjbXiDZcVhOBSzKn3o9LgRLLMRNuru8=
 github.com/mitchellh/mapstructure v0.0.0-20180203102830-a4e142e9c047/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/nishanths/predeclared v0.0.0-20200524104333-86fad755b4d3/go.mod h1:nt3d53pc1VYcphSCIaYAJtnPYnr3Zyn8fMq2wvPGPso=
diff --git a/lib/confutil/chosen_cases_filter.go b/lib/confutil/chosen_cases_filter.go
new file mode 100644
index 000000000..bd1619a5c
--- /dev/null
+++ b/lib/confutil/chosen_cases_filter.go
@@ -0,0 +1,15 @@
+package confutil
+
+// Creates filter that returns true if ammo tag is in chosenCases. If no chosenCases provided - returns true
+func IsChosenCase(checkCase string, chosenCases []string) bool {
+	if len(chosenCases) == 0 {
+		return true
+	}
+
+	for _, c := range chosenCases {
+		if c == checkCase {
+			return true
+		}
+	}
+	return false
+}
diff --git a/lib/confutil/chosen_cases_filter_test.go b/lib/confutil/chosen_cases_filter_test.go
new file mode 100644
index 000000000..c73a42c69
--- /dev/null
+++ b/lib/confutil/chosen_cases_filter_test.go
@@ -0,0 +1,25 @@
+package confutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestChosenCases(t *testing.T) {
+	type testCase struct {
+		ammoTag  string
+		expected bool
+	}
+
+	cases := []string{"tag1", "tag3"}
+
+	tests := []testCase{
+		{"tag1", true},
+		{"tag2", false},
+	}
+
+	for _, tc := range tests {
+		assert.Equal(t, tc.expected, IsChosenCase(tc.ammoTag, cases))
+	}
+}
diff --git a/lib/confutil/custom_tag_resolver.go b/lib/confutil/custom_tag_resolver.go
new file mode 100644
index 000000000..6fd2be5a0
--- /dev/null
+++ b/lib/confutil/custom_tag_resolver.go
@@ -0,0 +1,178 @@
+package confutil
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+var (
+	notoken                         = ""
+	ErrNoTagsFound                  = errors.New("no tags found")
+	ErrUnsupportedKind              = errors.New("unsupported kind")
+	ErrCantCastVariableToTargetType = errors.New("can't cast variable")
+	ErrResolverNotRegistered        = errors.New("unknown tag type")
+)
+
+type TagResolver func(string) (string, error)
+
+type tagEntry struct {
+	tagType string
+	string  string
+	varname string
+}
+
+var resolvers map[string]TagResolver = make(map[string]TagResolver)
+
+// Register custom tag resolver for config variables
+func RegisterTagResolver(tagType string, resolver TagResolver) {
+	tagType = strings.ToLower(tagType)
+	// silent overwrite existing resolver
+	resolvers[tagType] = resolver
+}
+
+func getTagResolver(tagType string) (TagResolver, error) {
+	tagType = strings.ToLower(tagType)
+	r, ok := resolvers[tagType]
+	if !ok {
+		return nil, ErrResolverNotRegistered
+	}
+	return r, nil
+}
+
+// Resolve config variables in format ${tagType:variable}
+func ResolveCustomTags(s string, targetType reflect.Type) (interface{}, error) {
+	tokens, err := findTags(s)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(tokens) == 0 {
+		return s, ErrNoTagsFound
+	}
+
+	res := s
+	for _, t := range tokens {
+		resolver, err := getTagResolver(t.tagType)
+		if err == ErrResolverNotRegistered {
+			continue
+		} else if err != nil {
+			return nil, err
+		}
+
+		resolved, err := resolver(t.varname)
+		if err != nil {
+			return nil, err
+		}
+		res = strings.ReplaceAll(res, t.string, resolved)
+	}
+
+	// cast to target kind only if the whole value is a tag
+	// otherwise let other hooks process result
+	if len(tokens) == 1 && strings.TrimSpace(s) == tokens[0].string {
+		return cast(res, targetType)
+	} else {
+		return res, nil
+	}
+}
+
+func findTags(s string) ([]*tagEntry, error) {
+	tagRegexp := regexp.MustCompile(`\$\{(?:([^}]+?):)?([^{}]+?)\}`)
+	tokensFound := tagRegexp.FindAllStringSubmatch(s, -1)
+	result := make([]*tagEntry, 0, len(tokensFound))
+
+	for _, token := range tokensFound {
+		tag := &tagEntry{
+			tagType: strings.TrimSpace(token[1]),
+			varname: strings.TrimSpace(token[2]),
+			string:  token[0],
+		}
+		result = append(result, tag)
+	}
+
+	return result, nil
+}
+
+func cast(v string, t reflect.Type) (interface{}, error) {
+	switch t.Kind() {
+	case reflect.Bool:
+		return castBool(v)
+	case reflect.Int,
+		reflect.Int8,
+		reflect.Int16,
+		reflect.Int32,
+		reflect.Int64,
+		reflect.Uint,
+		reflect.Uint8,
+		reflect.Uint16,
+		reflect.Uint32,
+		reflect.Uint64:
+		return castInt(v, t)
+	case reflect.Float32,
+		reflect.Float64:
+		return castFloat(v, t)
+	case reflect.String:
+		return v, nil
+	}
+	return nil, ErrUnsupportedKind
+}
+
+func castBool(v string) (interface{}, error) {
+	res, err := strconv.ParseBool(v)
+	if err != nil {
+		return false, fmt.Errorf("'%s' cast to bool failed: %w", v, ErrCantCastVariableToTargetType)
+	}
+
+	return res, nil
+}
+
+func castInt(v string, t reflect.Type) (interface{}, error) {
+	intV, err := strconv.ParseInt(v, 0, t.Bits())
+	if err != nil {
+		return nil, fmt.Errorf("'%s' cast to %s failed: %w", v, t, ErrCantCastVariableToTargetType)
+	}
+
+	switch t.Kind() {
+	case reflect.Int:
+		return int(intV), nil
+	case reflect.Int8:
+		return int8(intV), nil
+	case reflect.Int16:
+		return int16(intV), nil
+	case reflect.Int32:
+		return int32(intV), nil
+	case reflect.Int64:
+		return int64(intV), nil
+	case reflect.Uint:
+		return uint(intV), nil
+	case reflect.Uint8:
+		return uint8(intV), nil
+	case reflect.Uint16:
+		return uint16(intV), nil
+	case reflect.Uint32:
+		return uint32(intV), nil
+	case reflect.Uint64:
+		return uint64(intV), nil
+	}
+
+	return nil, ErrUnsupportedKind
+}
+
+func castFloat(v string, t reflect.Type) (interface{}, error) {
+	intV, err := strconv.ParseFloat(v, 64)
+	if err != nil {
+		return 0.0, fmt.Errorf("'%s' cast to %s failed: %w", v, t, ErrCantCastVariableToTargetType)
+	}
+
+	switch t.Kind() {
+	case reflect.Float32:
+		return float32(intV), nil
+	case reflect.Float64:
+		return float64(intV), nil
+	}
+
+	return nil, ErrUnsupportedKind
+}
diff --git a/lib/confutil/custom_tag_resolver_test.go b/lib/confutil/custom_tag_resolver_test.go
new file mode 100644
index 000000000..5a887d580
--- /dev/null
+++ b/lib/confutil/custom_tag_resolver_test.go
@@ -0,0 +1,122 @@
+package confutil
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStringToExpectedCast(t *testing.T) {
+	type testCase struct {
+		val      string
+		expected interface{}
+		err      error
+	}
+
+	tests := []testCase{
+		{"True", true, nil},
+		{"T", true, nil},
+		{"t", true, nil},
+		{"TRUE", true, nil},
+		{"true", true, nil},
+		{"1", true, nil},
+		{"False", false, nil},
+		{"false", false, nil},
+		{"0", false, nil},
+		{"f", false, nil},
+		{"", false, ErrCantCastVariableToTargetType},
+
+		{"11", uint(11), nil},
+		{"10", uint8(10), nil},
+		{"10", uint16(10), nil},
+		{"10", uint32(10), nil},
+		{"10", uint64(10), nil},
+		{"11", int(11), nil},
+		{"10", int8(10), nil},
+		{"10", int16(10), nil},
+		{"10", int32(10), nil},
+		{"10", int64(10), nil},
+		{"", int(0), ErrCantCastVariableToTargetType},
+		{"asdf", int(0), ErrCantCastVariableToTargetType},
+		{" -14", int(0), ErrCantCastVariableToTargetType},
+
+		{"-10", float32(-10), nil},
+		{"10.23", float32(10.23), nil},
+		{"-10", float64(-10), nil},
+		{"10.23", float64(10.23), nil},
+		{"", float64(0), ErrCantCastVariableToTargetType},
+		{"asdf", float64(0), ErrCantCastVariableToTargetType},
+		{" -14", float64(0), ErrCantCastVariableToTargetType},
+
+		{"10", "10", nil},
+		{"value-port", "value-port", nil},
+		{"", "", nil},
+	}
+
+	for _, test := range tests {
+		expectedType := reflect.TypeOf(test.expected)
+		t.Run(fmt.Sprintf("Test string to %s cast", expectedType), func(t *testing.T) {
+			actual, err := cast(test.val, expectedType)
+			if test.err == nil {
+				assert.NoError(t, err)
+				assert.Exactly(t, test.expected, actual)
+			} else {
+				assert.ErrorIs(t, err, test.err)
+			}
+
+		})
+	}
+}
+
+func TestFindTokens(t *testing.T) {
+	type testCase struct {
+		val      string
+		expected []*tagEntry
+		err      error
+	}
+
+	tests := []testCase{
+		{
+			"${token}",
+			[]*tagEntry{{string: "${token}", tagType: "", varname: "token"}},
+			nil,
+		},
+		{
+			"${token}-${ second\t}",
+			[]*tagEntry{
+				{string: "${token}", tagType: "", varname: "token"},
+				{string: "${ second\t}", tagType: "", varname: "second"},
+			},
+			nil,
+		},
+		{
+			"asdf${ee:token}aa",
+			[]*tagEntry{
+				{string: "${ee:token}", tagType: "ee", varname: "token"},
+			},
+			nil,
+		},
+		{
+			"asdf${ee: to:ken}aa-${ e2 :to  }ken}",
+			[]*tagEntry{
+				{string: "${ee: to:ken}", tagType: "ee", varname: "to:ken"},
+				{string: "${ e2 :to  }", tagType: "e2", varname: "to"},
+			},
+			nil,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("Test findTokens in %s", test.val), func(t *testing.T) {
+			actual, err := findTags(test.val)
+			if test.err == nil {
+				assert.NoError(t, err)
+				assert.EqualValues(t, test.expected, actual)
+			} else {
+				assert.ErrorIs(t, err, test.err)
+			}
+		})
+	}
+}
diff --git a/lib/confutil/env_var_resolver.go b/lib/confutil/env_var_resolver.go
new file mode 100644
index 000000000..a3cb79072
--- /dev/null
+++ b/lib/confutil/env_var_resolver.go
@@ -0,0 +1,24 @@
+package confutil
+
+import (
+	"errors"
+	"fmt"
+	"os"
+)
+
+var ErrEnvVariableNotProvided error = errors.New("env variable not set")
+
+// Resolve custom tag token with env variable value
+var EnvTagResolver TagResolver = envTokenResolver
+
+func envTokenResolver(in string) (string, error) {
+	// TODO: windows os is case-insensitive for env variables,
+	// so it may requre to load all vars and lookup for env var manually
+
+	val, ok := os.LookupEnv(in)
+	if !ok {
+		return "", fmt.Errorf("%s: %w", in, ErrEnvVariableNotProvided)
+	}
+
+	return val, nil
+}
diff --git a/lib/confutil/env_var_resolver_test.go b/lib/confutil/env_var_resolver_test.go
new file mode 100644
index 000000000..0d452032b
--- /dev/null
+++ b/lib/confutil/env_var_resolver_test.go
@@ -0,0 +1,37 @@
+package confutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEnvVarResolver(t *testing.T) {
+	type testCase struct {
+		varname string
+		val     string
+		err     error
+	}
+
+	tests := []testCase{
+		{"SOME_BOOL", "True", nil},
+		{"INT_VALUE", "10", nil},
+		{"V_NAME", "10", nil},
+	}
+
+	for _, test := range tests {
+		t.Setenv(test.varname, test.val)
+	}
+
+	tests = append(tests, testCase{"NOT_EXISTS", "", ErrEnvVariableNotProvided})
+
+	for _, test := range tests {
+		actual, err := envTokenResolver(test.varname)
+		if test.err != nil {
+			assert.ErrorIs(t, err, test.err)
+		} else {
+			assert.NoError(t, err)
+			assert.Exactly(t, test.val, actual)
+		}
+	}
+}
diff --git a/lib/netutil/dial.go b/lib/netutil/dial.go
index cc7b7527b..e03de0a9d 100644
--- a/lib/netutil/dial.go
+++ b/lib/netutil/dial.go
@@ -9,6 +9,7 @@ import (
 	"context"
 	"net"
 	"sync"
+	"time"
 
 	"github.com/pkg/errors"
 )
@@ -56,8 +57,8 @@ var DefaultDNSCache = &SimpleDNSCache{}
 // This method has much more overhead, but get guaranteed reachable resolved addr.
 // Example: host is resolved to IPv4 and IPv6, but IPv4 is not working on machine.
 // LookupReachable will return IPv6 in that case.
-func LookupReachable(addr string) (string, error) {
-	d := net.Dialer{DualStack: true}
+func LookupReachable(addr string, timeout time.Duration) (string, error) {
+	d := net.Dialer{DualStack: true, Timeout: timeout}
 	conn, err := d.Dial("tcp", addr)
 	if err != nil {
 		return "", err
diff --git a/lib/netutil/netutil_suite_test.go b/lib/netutil/netutil_suite_test.go
index 8103e13d0..a397d4121 100644
--- a/lib/netutil/netutil_suite_test.go
+++ b/lib/netutil/netutil_suite_test.go
@@ -5,10 +5,10 @@ import (
 	"net"
 	"strconv"
 	"testing"
+	"time"
 
 	"github.com/onsi/ginkgo"
 	"github.com/onsi/gomega"
-
 	"github.com/pkg/errors"
 	"github.com/yandex/pandora/lib/ginkgoutil"
 	netmock "github.com/yandex/pandora/lib/netutil/mocks"
@@ -29,7 +29,7 @@ var _ = ginkgo.Describe("DNS", func() {
 		addr := "localhost:" + port
 		expectedResolved := "127.0.0.1:" + port
 
-		resolved, err := LookupReachable(addr)
+		resolved, err := LookupReachable(addr, time.Second)
 		gomega.Expect(err).NotTo(gomega.HaveOccurred())
 		gomega.Expect(resolved).To(gomega.Equal(expectedResolved))
 	})
diff --git a/lib/tag/debug.go b/lib/tag/debug.go
index aaa7c857c..ee36c25b0 100644
--- a/lib/tag/debug.go
+++ b/lib/tag/debug.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 // Author: Vladimir Skipor <skipor@yandex-team.ru>
 
+//go:build debug
 // +build debug
 
 package tag
diff --git a/lib/tag/race.go b/lib/tag/race.go
index a19547375..0cdaf0afb 100644
--- a/lib/tag/race.go
+++ b/lib/tag/race.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 // Author: Vladimir Skipor <skipor@yandex-team.ru>
 
+//go:build race
 // +build race
 
 package tag
diff --git a/main.go b/main.go
index bcad8b157..dfd8cba40 100644
--- a/main.go
+++ b/main.go
@@ -7,7 +7,6 @@ package main
 
 import (
 	"github.com/spf13/afero"
-
 	"github.com/yandex/pandora/cli"
 	example "github.com/yandex/pandora/components/example/import"
 	grpc "github.com/yandex/pandora/components/grpc/import"
diff --git a/test-sync.txt b/test-sync.txt
new file mode 100644
index 000000000..7c9415122
--- /dev/null
+++ b/test-sync.txt
@@ -0,0 +1 @@
+test-sync-with-arcadia