kubernetes上部署jenkins并使用ingress-nginx提供域名访问

在 K8S 中部署 jenkins

github上有一个1.5k star的项目：https://github.com/jenkinsci/kubernetes-plugin

上面提供了jenkins在kubernetes中容器化的部署方式，以及yaml文件，现在直接 git clone 下来。

[root@master ~]# cd /work/
[root@master work]# git clone https://github.com/jenkinsci/kubernetes-plugin.git

克隆完之后进入到这个目录。

[root@master work]# cd kubernetes-plugin/src/main/kubernetes/
[root@master kubernetes]# ls
jenkins.yml  service-account.yml

直接克隆下来的文件，可能在某些k8s版本上会报错，请根据报错提示修改；

下面的yaml在k8s v1.16.3版本上做过了测试。

可以看到有两个文件，service-account.yml 文件是创建 RBAC 授权相关的东西，这个不要动，主要看一下 jenkins.yml，需要修改一下，修改后的文件如下：

# jenkins

---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: jenkins
  labels:
    name: jenkins
spec:
  selector:
    matchLabels:
      name: jenkins
  serviceName: jenkins
  replicas: 1
  updateStrategy:
    type: RollingUpdate
  template:
    metadata:
      name: jenkins
      labels:
        name: jenkins
    spec:
      terminationGracePeriodSeconds: 10
      serviceAccountName: jenkins
      containers:
        - name: jenkins
          command: 
          - /sbin/tini 
          - /usr/local/bin/jenkins.sh
          - --prefix=/jenkins
          image: jenkins/jenkins:lts-alpine
          imagePullPolicy: Always
          ports:
            - containerPort: 8080
            - containerPort: 50000
          resources:
            limits:
              cpu: 1
              memory: 1Gi
            requests:
              cpu: 0.5
              memory: 500Mi
          env:
            - name: LIMITS_MEMORY
              valueFrom:
                resourceFieldRef:
                  resource: limits.memory
                  divisor: 1Mi
            - name: JAVA_OPTS
              # value: -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -XX:MaxRAMFraction=1 -XshowSettings:vm -Dhudson.slaves.NodeProvisioner.initialDelay=0 -Dhudson.slaves.NodeProvisioner.MARGIN=50 -Dhudson.slaves.NodeProvisioner.MARGIN0=0.85
              value: -Xmx$(LIMITS_MEMORY)m -XshowSettings:vm -Dhudson.slaves.NodeProvisioner.initialDelay=0 -Dhudson.slaves.NodeProvisioner.MARGIN=50 -Dhudson.slaves.NodeProvisioner.MARGIN0=0.85 -D--prefix=/jenkins
          volumeMounts:
            - name: jenkins-home
              mountPath: /var/jenkins_home
          livenessProbe:
            httpGet:
              path: /jenkins/login
              port: 8080
            initialDelaySeconds: 60
            timeoutSeconds: 5
            failureThreshold: 12 # ~2 minutes
          readinessProbe:
            httpGet:
              path: /jenkins/login
              port: 8080
            initialDelaySeconds: 60
            timeoutSeconds: 5
            failureThreshold: 12 
      securityContext:
        fsGroup: 1000
      volumes:
      - hostPath:
          path: /data/jenkins
        name: jenkins-home

---
apiVersion: v1
kind: Service
metadata:
  name: jenkins
spec:
  selector:
    name: jenkins
  ports:
    -
      name: http
      port: 80
      targetPort: 8080
      protocol: TCP
    -
      name: agent
      port: 50000
      protocol: TCP

---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: jenkins
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    kubernetes.io/tls-acme: "true"
    # "413 Request Entity Too Large" uploading plugins, increase client_max_body_size
    nginx.ingress.kubernetes.io/proxy-body-size: 50m
    nginx.ingress.kubernetes.io/proxy-request-buffering: "off"
    # For nginx-ingress controller < 0.9.0.beta-18
    ingress.kubernetes.io/ssl-redirect: "true"
    # "413 Request Entity Too Large" uploading plugins, increase client_max_body_size
    ingress.kubernetes.io/proxy-body-size: 50m
    ingress.kubernetes.io/proxy-request-buffering: "off"
spec:
  rules:
  - http:
      paths:
      - path: /jenkins
        backend:
          serviceName: jenkins
          servicePort: 80
    host: example.cn
  tls:
  - hosts:
    - example.cn
    secretName: litemall-admin-secret

注意到，上面yaml中主要修改ingress中的host为自己的域名，我的域名是在阿里备案过的域名（如果有国外的机器，不用备案也可以），而且申请了阿里的免费https证书，将证书配置到ingress-nginx中（通过创建一个secret，secret中包含了证书的信息）；

还有需要修改ingress中的path为带前缀的：/jenkins，因为对于入口网关:ingress-nginx，有很多路径为/的服务创建ingress去暴露，为了区分，所以通过带前缀的方式。这样就需要在Statefulset的podTemplate中配置jenkins的参数--prefix=/jenkins，这样Pod启动执行command：/sbin/tini -- /usr/local/bin/jenkins.sh --prefix=/jenkins
后，jenkins.sh脚本中就会调用java -jar jenkins.war --prefix=/jenkins将参数传入。

默认path加了/jenkins前缀后，同时对应的修改健康检查中的path为/jenkins/login；

另外，jenkins的数据目录需要做持久化，也就是/var/jenkins_home，jenkins 所有的数据都是存在这个目录下面的。

如果没有公网域名，那就没必要创建Ingress，直接通过Service的NodePort方式去暴露，最后通过{k8s集群任一主机IP}:{nodePort端口}/jenkins方式去访问。

最后顺便贴出Service Account的配置，这里对github上的原有yaml没做修改：

# In GKE need to get RBAC permissions first with
# kubectl create clusterrolebinding cluster-admin-binding --clusterrole=cluster-admin [--user=|--group=]

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: jenkins

---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: jenkins
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["create","delete","get","list","patch","update","watch"]
- apiGroups: [""]
  resources: ["pods/exec"]
  verbs: ["create","delete","get","list","patch","update","watch"]
- apiGroups: [""]
  resources: ["pods/log"]
  verbs: ["get","list","watch"]
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get"]

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: jenkins
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: jenkins
subjects:
- kind: ServiceAccount
  name: jenkins

最后通过域名去访问：