Monitoring Containerized Elixir

Transcript

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   Monitoring Containerized Elixir

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   .｡oO(さっちゃんですよヾ(〃l _ l)ﾉﾞ☆) @ Mackerel.io / Hatena.ne.jp

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   Imagine, you have a great Elixir app.

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   Imagine, you have a great Elixir app. And will be

   working it on Docker
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   Imagine, you have a great Elixir app. And will be

   working it on Docker on Kubernetes.
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   Why container, Docker? Container is an abstract layer over infrastructure.

   It runs everywhere. It easy to create, share, transfer & run.
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   Why Kubernetes? K8s is a common language. K8s can run

   every types of applications.
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   Elixir on Containers https://speakerdeck.com/ne_sachirou/elixir-on- containers s/:distillery/Mix.Release/

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   When you've deployed the app on K8s. How to monitor

   it?
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    Why Monitoring? Is your app works well? Know how your

    app works. What caused when your app is broken. Keep your app observable.
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    Liveness check Is your app is living or not?

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    K8s has liveness probe. --- apiVersion: apps/v1 kind: Deployment spec:

    template: spec: containers: - name: app livenessProbe: httpGet: path: /ops/heartbeat port: 4000
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    How to check your app is live or not?

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    KomachiHeartbeat https://hex.pm/packages/komachi_heartbeat Vital monitoring Elixir Web application.

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    KomachiHeartbeat The name is originate from a great Rubygems :

    https://rubygems.org/gems/komachi_heartbeat
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    Add KomachiHeartbeat. defmodule Example.Router do use Plug.Router plug(:match) plug(:dispatch) forward("/ops",

    to: KomachiHeartbeat) end defmodule ExampleWeb.Router do use ExampleWeb, :router forward("/ops", KomachiHeartbeat) end
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    Check it. % curl http://localhost/ops/heartbeat heartbeat:ok Also available from Zabbix,

    ALB health check or Mackerel's "External Http monitor (外形監視)".
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    Error collection Listening canary song.

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    Sentry https://sentry.io/ Collect & sort errors. Show the error environments:

    stacktrace, HTTP params, app host, release ver… Assign & resolve issue. Integrate with Sass: Slack, GitHub…
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    Add https://hex.pm/packages/sentry in your app. defmodule Example.Application do use Application

    def start(_type, _args) do Logger.add_backend(Sentry.LoggerBackend) … end defmodule Example.Router do use Sentry.Plug … end & add many metadata, by yourself (・﹏・)
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    Metrics monitoring Know the app behaviour & detect anomary.

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    Prometheus + Grafana + deadtrickster/beam-dashboards Beautiful. But to keep Prometheus

    servers have many toils.
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    Mackerel https://mackerel.io

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    Add mackerel-container-agent as a sidecar. --- apiVersion: apps/v1 kind: Deployment

    spec: template: spec: containers: - name: app … - name: mackerel-container-agent image: mackerel/mackerel-container-agent:latest imagePullPolicy: Always resources: limits: {memory: 128Mi} env: - {name: MACKEREL_CONTAINER_PLATFORM, value: kubernetes} - name: MACKEREL_KUBERNETES_KUBELET_HOST valueFrom: fieldRef: fieldPath: status.hostIP - name: MACKEREL_KUBERNETES_NAMESPACE valueFrom: fieldRef: {fieldPath: metadata.namespace} - name: MACKEREL_KUBERNETES_POD_NAME valueFrom: fieldRef: {fieldPath: metadata.name} - {name: MACKEREL_ROLES, value: example:app} envFrom: - secretRef: {name: mackerel}
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    apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization … secretGenerator: - name: mackerel type:

    Opaque files: [MACKEREL_APIKEY=secret/MACKEREL_APIKEY]
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    None
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    OK. I see container's metrics. How about BEAM metrics?

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    KomachiHeartbeat + mackerel- plugin-json https://hex.pm/packages/komachi_heartbeat Vital monitoring Elixir Web application.

    https://github.com/mackerelio/mackerel-plugin-json Json custom metrics plugin for mackerel.io agent.
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    KomachiHeartbeat has /stats endpoint that returns app's stats in JSON.

    mackerel-plugin-json posts any data gotten from JSON API as Mackerel custome metrics.
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    We have KomachiHeartbeat.BeamVital . https://github.com/ne- sachirou/ex_komachi_heartbeat/pull/29 (Sorry for under development.)

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    Add KomachiHeartbeat.BeamVital . defmodule TeijiBot.Router do use Plug.Router plug(:match) plug(:dispatch)

    forward( "/ops", to: KomachiHeartbeat, init_opts: [vitals: [KomachiHeartbeat.BeamVital]] ) end
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    Configure mackerel-plugin-json. --- apiVersion: apps/v1 kind: Deployment spec: template: spec:

    volumes: - name: mackerel-agent-config configMap: name: mackerel-agent-config containers: - name: app … - name: mackerel-container-agent image: mackerel/mackerel-container-agent:plugins … env: - {name: MACKEREL_AGENT_CONFIG, value: /etc/mackerel/mackerel.yaml} … volumeMounts: - name: mackerel-agent-config mountPath: /etc/mackerel readOnly: true
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    --- apiVersion: v1 kind: ConfigMap metadata: name: mackerel-agent-config data: mackerel.yaml:

    | plugin: metrics: json: command: | mackerel-plugin-json \ -url="http://localhost:4000/ops/stats" \ -prefix='beam'
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    None
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    Current metrics : atom_count memory_ets_tables memory_system_bytes_total atom, binary, code, ets,

    other port_count process_count (More, under development.)