Ticketmaster lbAPI

The lbAPI is a web service that enables users to manage Virtual IPs (VIP) across multiple load balancers (e.g. AVI Networks and Citrix Netscaler ADC). The goal is to provide users an abstraction layer that follows a single pattern for creating virtual server definitions.

Components

• Deployment Model: Docker
• Language: go1.14.6
• Database (External): PostgreSQL
• Current Major release: v1.0

High Level Architecture

Routes

The lbAPI exposes two primary routes: loadbalancer and virtualserver. These routes include methods that will parse a JSON payload, validate its content, and forward it to a load balancer for processing.

These methods include:

• Fetch (HTTP_GET) - Retrieves data directly from the database.
• Modify (HTTP_PUT) - modifies the resource on both the loadbalancer and database.
• Create (HTTP_POST) - Creates the resource on both the loadbalancer and database.
• Delete (HTTP_DELETE) - Deletes the resource on both the loadbalancer and database.

Not included above, there is an administrative route called source. This route is solely meant for populating the database with current resource meta data.

Additional Features

• Automatic load balancer assignment based on target network
  • Looks at available routes on each load balancer and determines whether or not the back-ends or service IP can live on that cluster, then assigns it.
  • Uses the "platform" field to explicitly assign a VIP to a load balancer of a specific type. If empty, the API will assign the first matching load balancer.
• Infoblox Integration
  • CRUD DNS records pertaining to VIPs.
  • Create a standard HOST record named prd-IP-ADDRESS.lb. is created whenever a new VIP is generated.
  • Users can provide alternate names in the virtualserver payload under the dns[] entity and the API will automatically create them. All records created by the API are HOST records, so reverse DNS lookups will resolve them.
  • Automatically retrieve next available IP address from DHCP subnet. This decision is made by determining the subnet of the back-end pool members and using that to isolate the VRF Context. Embedded in the logic is a MAC address check that queries Ticketmaster's Network API to determine whether or not there has been an ARP reply associated with the IP. This is required to ensure that the IP is truly available for assignment.
• Product Code Authorization
  • LDAP-based login group level authorization based on product code membership. In short, VIPs under a product code can only be modified by a member of the product code security group (e.g., prd1234-LimitedAccess).
• Certificate Management (AVI VIPs only)
  • As long as the service_type is set to https, team members can bind a certificate to their VIP. You can bind certificates to both the vip and its pool. Note that pools with mapped certificates are solely meant for certificate authentication to the back end servers.
  • Users can create/replace certificates using the virtualserver model.
  • We support both ECDSA (Preferred) and RSA certificates.
  • When a VIP is deleted, the certificate is deleted. Each VIP has its own unique instance of a certificate (even though the same certificate may be used by multiple VIPs).

Packages

This section is divided into two main categories: internal and external packages. Internal packages refer specifically to all the logic written specifically for the API and provide its core functionality. External packages are typically written and supported by a third-party, and extend the functionality of the API.

Internal Packages

Package Name	Route	Description	Modifies Load Balancer
handler		Maps functions to routes.	n/a
common		Provides functions for Fetch, Modify, Create, and Delete operations.	n/a
loadbalancer	api/v1/loadbalancer	Provides loadbalancer specific logic.	no
virtualserver	api/v1/virtualserver	Provides virtualserver specific logic.	yes
pool		Provides pool/backend server logic.	yes
poolgroup		Provides pool group logic. (AVI only)	yes
certificate		Provides certificate logic - (AVI only)	yes
healthmonitor		Provides health monitor logic.	yes
persistence		Provides persistence monitor logic.	yes
migrate	/api/v1/migrate/virtualserver	Provides migration logic to move between Netscaler and AVI.	yes
recycle	/api/v1/recycle	Repository for deleted records.	no
simple	/api/v1/simple/virtualserver	Route for returning a simplified recordsets (used by the UI).	no
backup	/api/v1/backup/virtualserver	Posts changed records to GIT for backup.	no
infoblox		Provides infoblox logic.	no
routeconfig		*Common object settings for each route.	no
sdkfork		Provides decision making logic to route requests based on load balancer type	no

handler

The handler package includes functions that are directly mapped to a gin.RouteHandler. To avoid defining resource specific routes, the handler package provides functions that accept shared.Common as a generic interface (e.g., definition) and tests the definition for the presence of common functions (i.e., Fetch, Modify, etc.).

To dynamically add routes to a resource, add a reference to the route to the bootstrap package and call it from main.go. Each resource will invoke it's own common.New() object which will map the appropriate CRUD routes to it. For example:will automatically

func NewLoadBalancer() *LoadBalancer {
	filter := make(map[string][]string)
	filter["loadbalancerip"] = []string{}
	////////////////////////////////////////////////////////////////////////////
	o := new(LoadBalancer)
	o.Common = common.New()
	////////////////////////////////////////////////////////////////////////////
	o.Database.Table = "loadbalancers"
	o.Database.Filter = filter
	o.Database.Validate = o.validate
	////////////////////////////////////////////////////////////////////////////
	o.ModifyLb = false
	o.Route = "loadbalancer"
	////////////////////////////////////////////////////////////////////////////
	return o
}

The NewLoadBalancer constructor above invokes common.New which adds the routes and populates the filters and database settings for CRUD operations.

common

All resource specific packages (ie., loadbalancer, virtualserver, etc.) implement the common package. As such, the common package includes the "common" models and functions for creating, updating, retrieving and deleting records. This reduces the code footprint and ensures that each resource operates in the same manner.

In addition to providing the appropriate methods for handlers, common contains sdkfork, which routes load balancer logic to the appropriate SDK for processing. Each top-level handler method (i.e., Create, Fetch, etc), maps to a similar function within the load balancer SDK. For example, common.Create maps to either avi.Create or netscaler.Create. The decision is made according based on the client provided load_balancer_ip field. Each top-level handler queries the list of available load balancers and creates a map containing the cluster_ip of the load balancer and the manufacturer. A match process takes place and the manufacturer is forwarded to the SDK fork for decision-making.

loadbalancer

The loadbalancer package includes logic for retrieving and modifying load balancer records. These records include meta data such as serial number, firmware version and high availability partner.

virtualserver

The virtual package includes logic for retrieving and modifying virtual server (VIP) records. These records include meta data such as IP, port and service type.

Create

Sample Create payload.

  {
    "load_balancer_ip": "192.168.100.100",
    "data": {
      "name": "foo.mydomain.local",
      "service_type": "https",
      "ip": "192.168.0.10",
      "ports": [
        {
          "port": 443,
          "l4_profile": "tcp",
          "ssl_enabled": true
        },
        {
          "port": 80,
          "l4_profile": "tcp",
          "ssl_enabled": false
        }
      ],
      "dns": [
        "foo.mydomain.local"
      ],
      "enabled": true,
      "certificates": [
        {
          "certificate": `-----BEGIN CERTIFICATE-----
          -----END CERTIFICATE-----`,
          "key": {
            "private_key": `-----BEGIN PRIVATE KEY-----
            -----END PRIVATE KEY-----`
          }
        }
      ],
      "load_balancing_method": "roundrobin",
      "pools": [
        {
          "default_port": 80,
          "enabled": true,
          "ssl_enabled": false,
          "bindings": [
            {
              "server": {
                "ip": "192.168.0.20"
              },
              "enabled": true,
              "graceful_disable": false
            },
            {
              "server": {
                "ip": "192.168.0.21"
              },
              "enabled": true,
              "graceful_disable": false
            }
          ],
          "health_monitors": [
            {
              "type": "https",
              "response_codes": [
                "400",
                "200"
              ]
            }
          ],
          "persistence": {
            "type": "client-ip"
          }
        }
      ],
      "product_code": 1234
    }
  }

The preceding request will create:

1. A VIP on Avi called foo.mydomain.local. The creation ETL process will rename to prd1234-foo.mydomain.local-abc. The last three chars is a random id.
2. A DNS A record called prd1234-192-168-0-10.lb.mydomain.local. Optionally, you can populate the dns field (see virtualserver->model.go) with []string of fqdns. The create process will test the names, and then create them in Infoblox additional Host records with PTRs.
3. A pool on Avi called prd1234-foo.mydomain.local-abc-aas. The last three chars is a random id.
4. The pool will have two members, and both members will be enabled.
5. The VIP listens on 80 and 443 with 443 enabled for SSL, and the pool members are set to listen on port 80 via the default_port option.
6. The VIP will load balance requests, using roundrobin. Right now, we only support leastconnection and roundrobin.
7. Each port will have a l4_profile association. The default is tcp but we support udp as well.
8. If an IP address is not provided under $.data.ip, then the system will automatically assign one based on the first server binding in the first pool object.
9. If a load balancer ip ($.load_balancer_ip) is not provided, the system will automatically locate a suitable load balancer to host the record. If one is not found, the system will return an error indicating that a load balancer could not be found.

The API supports the creation of Netscaler services, but it is HIGHLY discouraged. A service is literally a 1:1 relationship where each service manages a single back-end server. As a result, one must create multiple services for load balancing. As a result, the API request would look like multiple pool entities with a single binding.

Both the Netscaler and AVI support 1:Many backend definitions where a single Netscaler servicegroup or Avi Pool can manage multiple backends. For simplicity purposes, we will refer to this backend definition as a pool. You can manage the state of the entire pool by toggling the enabled field, and quickly add members by adding new bindings. If default_port is set at the pool level, every binding will inherit the default_port value; otherwise, you can set the port value for each binding independently. Likewise, you can set the state of each binding independently of the pool.

Fetch

Fetching is fairly straightforward. You send a HTTP_GET to the virtualserver route and it will return all records in the database. If this is a new deployment, you will have to populate the database using ImportAll (see Getting Started).

The filter GET request looks like this:

http://<host>/api/v1/virtualserver?<key>=value

The following keys are supported:

• load_balancer_ip
• product_code
• dns
• Any top level key under the Data struct (e.g., name, port, etc.).
• limit, INTEGER, limits the number of records returned
• offset, INTEGER, used in conjunction with limit. Used to indicate the recordset page. For example, if your recordset is 10 lines long, and your limit is 5, your query would result in 2 pages. Page 1 would be records 1-5 and Page 2 would be 6-10.

We do not currently support filtering based pool or binding - it is in the works.

The value doesn't need to be exact. In fact, adding * anywhere within the value string will add a wildcard in its place. For example, name=*tix* will search for any vip that has the word tix in itemporary ro.

You can add even more granularity by adding & and additional keys. For example, name=*tix*&port=80 This will return any vip that has the word tix in it and uses port 80. Also, you can have more than one declaration of the same key (e.g., name=string&name=string2).

Modify

Modifying a record requires that you have the latest database record ID. I emphasize latest because these IDs are ephemeral, so they will rarely ever be the same. It is recommended that you search for the record, then record the ID. You can validate that you have the right ID by running executing an HTTP_GET to api/v1/virtualserver/<id>. That route will return all the facts pertaining to that VIP. Copy that return payload and paste it into an HTTP_PUT JSON request.

It is critical that you copy and paste the GET response into the PUT request in its entirety. The API compares what is being submitted to what is in the database and what it is on the loadbalancer. The user submitted request will overwrite whatever configurations are on the loadbalancer and in the database!

The Modify process is fairly comprehensive and designed to manage all of the vips dependencies. If you fail to include a binding in the PUT request, but the resource on the loadbalancer had a binding defined, the API will delete that binding on the loadbalancer. Likewise, if you forget to provide a value for enabled, the API will treat that field as false and disable the resource.

The Modify operation will also modify any changes to DNS names - to include the removal of CNames that are now longer in use.

Delete

The most frightening of all operations. Delete will delete the VIP and all of its dependencies. This ensures that any VIP created by the API is cleaned up after removal. This process will also delete the HOST records associated with the VIP.

pool

The pool package includes logic for retrieving and modifying pool records. These records include meta data such pool name and port. In addition, the pool package includes logic for modifying backend server bindings.

Unlike loadbalancer and virtualserver, there is no route dedicated to pool. The reason for this decision was to ensure that all pool operations are directly called by virtualserver.

External Packages

Package Name	Import Reference	Description	Vendor Supported
AVI SDK	github.com/avinetworks/sdk/go	Includes logic for managing AVI Networks load balancers. This includes methods for parsing data, API end-points and models.	yes
Netscaler SDK	github.com/ticketmaster/nitro-go-sdk	Includes logic for management Citrix Netscaler load balancers. This includes methods for parsing data, API end-points and models. This SDK is NOT vendor supported; however, it does utilize API end-points provided by the vendor.	no
Infoblox	github.com/ticketmaster/infoblox-go-sdk	Manages the creation of A/CName/PTR records.	no
Authentication	github.com/ticketmaster/authentication	Handles authentication and authorization.	no

TODO

• Add tests that were removed during sanitation process.
• Add documentation on authentication module.
• Add documentation for usage.
• Add options to config.toml to managing admin group, domains for infoblox and prometheus options.

Credits

• Author: Carlos Villanueva, [email protected]