K8S集群中部署jenkins

本文介绍在k8s环境中进行jenkins server的部署和配置。Jenkins是一个开源的、功能强大的持续集成和持续构建工具，采用master和salve架构，我们通过将jenkins集成环境部署在k8s集群中，可以实现jenkins slave按需创建、动态的伸缩。同时也提供了在k8s环境中应用的持续部署解决方案。

一、准备docker镜像文件

1、编译jenkins server docker镜像，默认的jenkis镜像已包含jdk，版本为1.8.0_171

# cat dockerfile
FROM jenkins
MAINTAINER [email protected]
ENV MAVEN_HOME /usr/local/maven
ENV JAVA_HOME  /usr/local/java
ENV CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
ENV PATH ${JAVA_HOME}/bin:${MAVEN_HOME}/bin:${PATH}

COPY apache-maven-3.5.4 /usr/local/maven
USER root
RUN mkdir -p /usr/local/maven/repository  &&  ln -s /usr/java/jdk1.8.0_171 /usr/local/java

# docker build -t harbor.59iedu.com/fjhb/jenkins:2018-08-12-v1 . 
# docker push harbor.59iedu.com/fjhb/jenkins:2018-08-12-v1

2、编译jenkins slave镜像
可以根据实际情况配置maven内网私服nexus，私服可以避免编译过程中通过公网下载依赖的jar包，配置私服需要把对应的setting.xml文件打包到apache-maven-3.5.4/conf目录下；
libltdl.so.7文件的获取路径为操作系统路径/usr/lib64/libltdl.so.7（实际上是个软链接，需要copy出来重命名）
slave.jar文件的获取路径为http://jenkins-server/jnlpJars/slave.jar

# cat Dockerfile
FROM openshift/base-centos7
MAINTAINER [email protected]
COPY apache-maven-3.5.4 /usr/local/maven
COPY jdk1.8.0_171       /usr/local/java
COPY kubectl            /usr/local/bin/kubectl
COPY libltdl.so.7 /usr/lib64/libltdl.so.7
COPY slave.jar /usr/share/jenkins/slave.jar 
COPY jenkins-slave /usr/local/bin/jenkins-slave

ENV HOME /home/jenkins
ENV AGENT_WORKDIR=/home/jenkins/agent
ENV JAVA_HOME /usr/local/java
ENV MAVEN_HOME /usr/local/maven/
ENV CLASSPATH .:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
ENV PATH ${JAVA_HOME}/bin:${MAVEN_HOME}/bin:${PATH} 
ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2"

RUN  chmod 755 /usr/share/jenkins \
  && chmod 644 /usr/share/jenkins/slave.jar 

RUN mkdir -p /home/jenkins/.jenkins \
 && mkdir -p ${AGENT_WORKDIR} \
 && yum -y install git subversion sshpass

VOLUME /home/jenkins/.jenkins
VOLUME ${AGENT_WORKDIR}
WORKDIR /home/jenkins

USER root
ENTRYPOINT ["jenkins-slave"]

# docker build -t harbor.59iedu.com/fjhb/jenkins-slave-toolkit:2018-08-10-v1 . 
# docker push harbor.59iedu.com/fjhb/jenkins-slave-toolkit:2018-08-10-v1

二、创建jenkins server

1、创建pv和pvc

# cat pv.yaml 
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: jenkins-master-vol
spec:
  capacity:
    storage: 5Gi 
  accessModes:
  - ReadWriteMany 
  nfs: 
    path: /home/jenkins
    server: 192.168.115.6
  persistentVolumeReclaimPolicy: Recycle 
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: maven-repository
spec:
  capacity:
    storage: 5Gi
  accessModes:
  - ReadWriteMany
  nfs:
    path: /home/maven
    server: 192.168.115.6
  persistentVolumeReclaimPolicy: Recycle

---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: jenkins-master-claim
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: maven-repository-claim
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

2、创建deployment和service

# cat deploy.yaml 
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: jenkins-master
spec:
  template:
    metadata:
      labels:
        name: jenkins-master
    spec:
      securityContext:
        fsGroup: 1000
      containers:
        - name: jenkins-master
          image: harbor.59iedu.com/fjhb/jenkins:2018-08-12-v1
          imagePullPolicy: Always
          ports:
            - containerPort: 8080
              name: http
            - containerPort: 50000
              name: agent
          volumeMounts:
            - name: jenkins-master-vol
              mountPath: /var/jenkins_home
            - name: maven-repository
              mountPath: /opt/maven/repository
            - name: docker
              mountPath: /usr/bin/docker
            - name: docker-sock
              mountPath: /var/run/docker.sock
      volumes:
        - name: jenkins-master-vol
          persistentVolumeClaim:
            claimName: jenkins-master-claim
        - name: maven-repository
          persistentVolumeClaim:
            claimName: maven-repository-claim
        - name: docker
          hostPath:
            path: /usr/bin/docker
        - name: docker-sock
          hostPath:
            path: /var/run/docker.sock
      serviceAccount: "jenkins-master"
      imagePullSecrets:
        - name: harborsecret

---
apiVersion: v1
kind: Service
metadata:
  name: jenkins-master
spec:
  type: NodePort
  ports:
    - port: 8080
      name: http
      targetPort: 8080
      nodePort: 8452
    - port: 50000
      name: agent
      nodePort: 50000
      targetPort: 50000 
  selector:
    name: jenkins-master

3、rbac授权

# cat sa.yaml 
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: jenkins-master
  namespace: default

---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: jenkins-master

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-master

roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: jenkins-master
subjects:
- kind: ServiceAccount
  name: jenkins-master
  namespace: default

4、default sa的rbac授权

# cat default-sa.yaml 
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: default-role

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: default-rolebinding

roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: default-role 
subjects:
- kind: ServiceAccount
  name: default
  namespace: default

三、初始化jenkins server

1、通过秘钥解锁jenkins（本文为了方便局域网其他主机访问，在vmware上配置了nat规则）

2、配置代理


3、安装插件


4、创建管理员账号

四、配置jenkins server

1、系统管理 —— 系统设置 —— 新增一个云”kubernetes”

Kubernetes URL: 输入api-server的地址
Jenkins URL: 输入jenkins server的服务名,端口8080
Jenkins Tunnel: 指的是slave连接master的端口，默认是50000

上图pod的模板名称为jenkins-slave，Container的模板名称为jnlp。这里有非常重要的两点要注意：
当Container的模板名称为jnlp的时候，jenkins-slave才会使用下面配置的docker镜像来启动pod，如果不为jnlp，则会使用默认的镜像jenkins/jnlp-slave:alpine

当使用自定义的docker镜像来启动jenkins slave pod的时候，下面的command to run（默认值是 sh -c）和arguments to pass to the command(默认值是cat)两个值需要清空。否则会出现jenkins slave jnlp连接不上master的情况，尝试100次连接之后销毁pod，然后再创建一个pod继续尝试连接，无限循环。

2、系统管理 —— Configure Global Security
确认jnlp agent的端口默认为50000，如果有修改，要保障这里的配置及前面部署deployment、service的端口配置、前文的云环境Jenkins Tunnel设置保持一致

3、系统管理 —— Global Tool Configuration
在这里设置对应的工具及环境变量，为了避免不必要的问题，前面通过dockerfile把jenkins server 和jenkins slave的环境变量调整成一致, java目录通过软连接的方式实现。

4、系统管理 —— 管理插件
推荐安装的几个插件：maven、 gitlab 、subversion、pipeline、Kubernetes Continuous Deploy、Publish Over SSH

完成插件安装后需要对jenkins server进行重启操作，可以点击“系统管理 ”——“准备关机”来完成重启操作，至此我们就完成了jenkins server在k8s环境中的部署和配置工作，下文开始介绍使用jenkins完成项目构建和发布。