摘要：可以利用特性，根據負載壓力來動態調整的數量。部署到集群以后，可以利用已有的日志系統和監控系統。即使用，也應該掛載到中，保證數據的安全。所有都部署到命名空間下，這個已經建好了。

本文主要講如何把drone部署到k8s集群當中，本身drone這種基于容器的pipeline方式，和k8s是相當契合的。這樣的好處有：

k8s集群守護drone-server 和drone-agent。

可以利用rpc特性，根據agent負載壓力來動態調整agent的數量。當然即使不動態調整，我們手動調整一下復制集的數目也是相當簡單的。

部署到k8s集群以后，可以利用k8s已有的日志系統和監控系統。

其實在接下來的文章系列中，我們會不斷側重于k8s相關。依舊是直接先上yaml文件，先來一個直觀的感受。

ConfigMap在此處可以理解為drone應用的配置文件。這里有關于server和agent一系列設置。不過在k8s中大家需要注意的是：更新configmap以后，對于掛載該configmap的應用，配置內容并不能立即生效，大約需要10s。

apiVersion: v1
kind: ConfigMap
metadata:
  name: drone-config
  namespace: devops
data:

  #######################
  # Drone Server Config #
  #######################

  # server host name
  server.host: drone.xxx.com
  # start the server in debug mode
  server.debug: "false"
  # open user registration
  server.open: "true"
  # database driver, defaul as sqlite3
  server.database.driver: sqlite3
  # database driver configuration string
  server.database.datasource: drone.sqlite

  # remote parameters (Gogs)
  server.remote.gogs: "true"
  server.remote.gogs.url: "http://gogs.xxx.com"
  server.remote.gogs.private.mode: "true"

  ######################
  # Drone Agent Config #
  ######################
  agent.debug: "false"
  agent.debug.pretty: "false"
  agent.max.procs: "1"
  agent.healthcheck: "true"

Secret文件，主要是存放一些秘鑰之類的。不過這里也是有坑的，這個secret用于server和angent通信，設置不對就會構建項目一直處于pending狀態。切記k8s中，secret需要base64。

echo -n "yourpassword" | base64
eW91cnBhc3N3b3Jk

apiVersion: v1
kind: Secret
metadata:
  name: drone-secrets
  namespace: devops
data:
  server.secret: eW91cnBhc3N3b3Jk

接下來就是drone-server的Deployment和Service和Ingress。此處為了簡單，用了sqlite數據庫，真正生產環境建議用mysql或是pgsql。即使用sqlite，也應該掛載到ceph中，保證數據的安全。這里直接hostpath。k8s中，應該做到存儲和計算的分離。

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: drone-server
  namespace: devops
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: drone-server
    spec:
      nodeSelector:
        net-type: external
      containers:
      - image: drone/drone:latest
        imagePullPolicy: Always
        name: drone-server
        ports:
        - containerPort: 8000
          protocol: TCP
        - containerPort: 9000
          protocol: TCP
        volumeMounts:
          # Persist our configs in an SQLite DB in here
          - name: drone-server-sqlite-db
            mountPath: /var/lib/drone
        resources:
          requests:
            cpu: 40m
            memory: 32Mi
        env:
        - name: DRONE_HOST
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.host
        - name: DRONE_OPEN
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.open
        - name: DRONE_DATABASE_DRIVER
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.database.driver
        - name: DRONE_DATABASE_DATASOURCE
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.database.datasource
        - name: DRONE_SECRET
          valueFrom:
            secretKeyRef:
              name: drone-secrets
              key: server.secret
        - name: DRONE_GOGS
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.remote.gogs
        - name: DRONE_GOGS_URL
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.remote.gogs.url
        - name: DRONE_GOGS_PRIVATE_MODE
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.remote.gogs.private.mode
        - name: DRONE_DEBUG
          valueFrom:
            configMapKeyRef:
              name: drone-config
              key: server.debug
      volumes:
        - name: drone-server-sqlite-db
          hostPath:
            path: /var/lib/drone

apiVersion: v1
kind: Service
metadata:
  name: drone-service
  namespace: devops
spec:
  ports:
  - name: http
    protocol: TCP
    port: 80
    targetPort: 8000
  - name: grpc
    protocol: TCP
    port: 9000
    targetPort: 9000
  selector:
    app: drone-server

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: drone-ingress
  namespace: devops
spec:
  rules:
  - host: drone.xxx.com
    http:
      paths:
      - backend:
          serviceName: drone-service
          servicePort: 80
        path: /

下面就是agent的部署文件了，replicas: 1 該項可以設置agent的數量，擴容起來特別方便。server和agent通過grpc的方式進行通信，主要端口是9000。

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: drone-agent
  namespace: devops
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: drone-agent
    spec:
      nodeSelector:
        net-type: external
      containers:
      - image: drone/agent:latest
        imagePullPolicy: Always
        name: drone-agent
        volumeMounts:
          # Enables Docker in Docker
          - name: docker-socket
            mountPath: /var/run/docker.sock
        resources:
          requests:
            cpu: 100m
            memory: 64Mi
        livenessProbe:
          httpGet:
            path: /healthz
            port: 3000
          initialDelaySeconds: 3
          periodSeconds: 3
        env:
        - name: DRONE_SERVER
          value: drone-service:9000
        # issue: https://github.com/drone/drone/issues/2048
        - name: DOCKER_API_VERSION
          value: "1.24"
        - name: DRONE_SECRET
          valueFrom:
            secretKeyRef:
              name: drone-secrets
              key: server.secret
      volumes:
        - name: docker-socket
          hostPath:
            path: /var/run/docker.sock

所有都部署到devops命名空間下，這個namespace已經建好了。當然如果沒有的話，需要提前創建。

項目github地址，這里有該系列的所有文件。