Run Cachet Docker on Kubernetes

Cachet is a beautiful and powerful open source status page system.

要部署  Cachet status page system 使用下列原件部署在 Kubernetes。

Cachet Docker Image
cachet-monitor

[~]$ git clone https://github.com/cachethq/Docker
[~]$ cd Docker/
[~]$ vim Dockerfile

增加 cachet-monitor binary 到 cachet

----

....

COPY conf/.env.docker /var/www/html/.env

RUN sudo wget https://github.com/CastawayLabs/cachet-monitor/releases/download/v3.0/cachet_monitor_linux_amd64 && \
    sudo chmod +x cachet_monitor_linux_amd64

VOLUME /var/www

...

----

[~]$ docker build -t test/cachet:2.3.10 .
建立 Cachet status page
[~]$ vim cachet-status-page.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: cachet-status-page
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: cachet-status-page
    spec:
      hostname: cachet
      # 部署到指定的 node 
      nodeSelector:
        cachet: "true"
      # 使用本機空間來存 postgresql
      volumes:
      - name: postgresql-data
        hostPath:
          path: /opt/etc/postgresql/data 
      containers:
      - name: postgres
        image: postgres:9.5
        env:
        - name: POSTGRES_USER
          value: "postgres"
        - name: POSTGRES_PASSWORD
          value: "postgres"
        volumeMounts:
        - name: postgresql-data
          mountPath: /var/lib/postgresql/data 
      - name: cachet
        image: test/cachet:2.3.10
        env:
        - name: DB_DRIVER
          value: "pgsql"
        - name: DB_HOST
          value: "cachet"
        - name: DB_DATABASE
          value: "postgres"
        - name: DB_USERNAME
          value: "postgres"
        - name: DB_PASSWORD
          value: "postgres"
---
apiVersion: v1
kind: Service
metadata:
  name: cachet-svc
  labels:
    app: cachet-status-page
spec:
  type: NodePort
  ports:
  - nodePort: 30000
    port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: cachet-status-page

[~]$ kubectl create -f cachet-status-page.yaml
到 http://{node-ip}:30000/ 設定 cachet-status-page
並建立被監控的 components 和 metrics
建立 Cachet monitor
[~]$ wget https://raw.githubusercontent.com/CastawayLabs/cachet-monitor/master/example.config.yml
[~]$ cp example.config.yml cachet-monitor.yaml
[~]$ vim cachet-monitor.yaml
更新 url 和 token, 更新相對應的 component_id 和 metric_id。
----
  url: http://{node-ip}:30000/api/v1
  # cachet api token
  token: zxcxzczxcxzcxzcxzczxc
  insecure: false
...
   # set to update component (either component_id or metric_id are required)
    component_id: 1
    # set to post lag to cachet metric (graph)
    metric_id: 1
    # custom templates (see readme for details) 錯誤輸出格式
    template:
      investigating:
        subject: "{{ .Monitor.Name }} - {{ .SystemName }}"
        message: "{{ .Monitor.Name }} check **failed** (server time: {{ .now }})\n\n{{ .FailReason }}"
      fixed:
        subject: "I HAVE BEEN FIXED"
    # seconds between checks  監控間隔
    interval: 1
...
----
把 monitor config 存到 k8s configmap 來使用
[~]$ kubectl create configmap cachet-monitor-config --from-file=cachet-monitor.yaml
[~]$ vim cachet-monitor.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: cachet-monitor
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: cachet-monitor
    spec:
      # 使用本機DNS 來monitor
      hostNetwork: true
      nodeSelector:
        cachet: "true"
      volumes:
      - name: cachet-monitor-yaml
        configMap:
          name: cachet-monitor-config 
          items:
          - key: cachet-monitor.yaml
            path: cachet-monitor.yaml
      containers:
      - name: cachet
        image: test/cachet:2.3.10
        command: ["/var/www/html/cachet_monitor_linux_amd64","-c","/var/www/html/cachet-monitor-config/cachet-monitor.yaml"]
        volumeMounts:
        - name: cachet-monitor-yaml
          mountPath: /var/www/html/cachet-monitor-config

[~]$ kubectl create -f cachet-monitor.yaml
[~]$ kubectl get pod
NAME                                  READY     STATUS    RESTARTS   AGE
cachet-monitor-2852706633-7x98h       1/1       Running   0          1d
cachet-status-page-2249399379-sjhk5   2/2       Running   0          1d
上述範例(cachet status page)使用本機儲存資訊，可改用其他volumes或persistent volumes/storageclasses