Epiphany Platform architecture can be divided into functional modules that realize closely related set of functionality.
Platform monitoring uses set of exporter components that the responsibility is to collect metrics. Following table shows which exporter is collecting metrics from each Epiphany component.
| Exporter | Component | Description |
|---|---|---|
Node exporter |
OS/Hardware metrics | description |
Kafka exporter |
Kafka metrics | description |
JMX exporter |
JVM metrics (Kafka, Zookeeper) | description |
HAProxy exporter |
HAProxy metrics | description |
cAdvisor |
Container metrics (Kubernetes, Docker) | description |
Prometheus is open-source system used for monitoring and alerting. Each exporter exposes http://server-name/metrics endpoint that contains monitoring data, then Prometheus collects this data in configured interval. To find more information about Prometheus use this link.
Once the data are collected, they can be shown in Grafana dashboards. Grafana in Epiphany Platform has Prometheus datasource configured by default. It uses PromQL to query Prometheus database. To read more about Grafana use this link.
When alert rule is met Prometheus generates alert.
The alert is handled by Alert Manager and depending on configuration is routed to Slack, PagerDuty, Email, etc. To read more about Alert Manager use this link.
Epiphany Platform logging uses Filebeat to collect logs. It reads data from following locations:
| Source | Purpose |
|---|---|
| /var/log/audit/audit.log | Logs from Linux audit daemon |
| /var/log/auth.log | System authorization information and user logins |
| /var/log/firewalld | Firewall logs |
| /var/log/haproxy.log | HAProxy logs |
| /var/log/kafka/server.log | Kafka logs |
| /var/log/messages | Global system messages |
| /var/log/secure | Logs from authentication and authorization |
| /var/log/syslog | System logs and events |
| /var/log/zookeeper/version-2/* | Zookeeper's logs |
| Docker containers | Kubernetes components that run in a container |
Filebeat, unlike Grafana, pushes data to database (Elasticsearch) instead of pulling them.
Read more about Filebeat.
Elasticsearch is highly scalable and full-text search enabled analytics engine. Epiphany Platform uses it for storage and analysis of logs.
Elasticsearch Curator is component that manages and cleans indices and snapshots. Epiphany uses Elasticsearch Curator to ensure that centralized logging will not completely fill disk space.
Kibana like Grafana is used in Epiphany for visualization, in addition it has full text search capabilities. Kibana uses Elasticsearch as datasource for logs, it allows to create full text queries, dashboards and analytics that are performed on logs.
Epiphany Platform benefits from Kubernetes capabilities. Product team creates a Docker enabled applications and using deployments installs them in a Kubernetes cluster.
Kubernetes Master is the component that provides control plane for a cluster. It handles an application's deployments and responds for events. Usually Kubernetes Master does not run application's pods.
Kubernetes Node component maintains running pods that Kubernetes Master delegates to work on the node. Usually there are many Kubernetes Nodes for single or many Kubernetes Masters.
Kafka is a distributed streaming and messaging platform.
Kafka Broker is a synonym for Kafka Server or Kafka Node. Brokers allow producers and consumers to publish and consume messages. Kafka is horizontally scalable - in short it means that adding new brokers increases Kafka cluster capacity.
Zookeeper in Epiphany Platform is used for distributed Kafka configuration management. Simplified: From application's perspective it provides information about location of topic/partition that application writes or reads.
Zookeepers are usually deployed in more than one instance - this is called Zookeepers ensemble.
HAProxy is a high performance load balancer. Applications deployed on Kubernetes can be exposed through HAProxy that supports TLS termination and supports multiple backends.
Epiphany Platform automates the configuration for backend and frontend of HAProxy.