在k8s+jenkins+github+dockerhub环境中用pipeline部署应用
用k8s+jenkins+github+dockerhub部署应用:
jenkins有两种方式实现CI/CD
1、自由风格,通过shell代码实现
2、pipeline流水线,通过jenkins代码或者jenkinsfile文件实现
Pipeline 有两种创建方法:
1、可以直接在 Jenkins 的 Web UI 界面中输入jenkins代码;
2、也可以通过创建一个 Jenkinsfile 脚本文件放入项目源码库中
构建一个新项目步骤:
1、在github上新建一个项目
2、在本地将项目克隆下来
3、编写代码,dockerfile,jenkinsfile,部署该应用的yaml文件
4、将项目代码push到github上
5、使用jenkins实现CI/CD
示例:
1、在github上新建一个项目nginx-demo(略)
2、克隆代码到本地192.168.1.244
$ git clone https://github.com/dongyali521521/nginx-demo
除了第一次clone,以后每次clone都要先删除原项目再clone
$ rm -rf nginx-demo
3、修改代码
$ cd nginx-demo/
$ vim index.html
4、将修改后的代码push到github
$ git add .
$ git commit -m "2222"
$ git push #需要输入github的用户名和密码
5、在jenkins中新建任务实现CI/CD
一般情况下,除了应用程序代码之外,dockerfile,jenkinsfile和部署该应用的yaml文件都放在源码中一起管理。
一个项目内至少包括如下文件:都需要在实现CI/CD前准备好
$ cd nginx-demo/
$ ls
Dockerfile Jenkinsfile xxx.yaml index.html README.md
在k8s中使用jenkins实现CI/CD(pipeline方式)又包括如下步骤:
1、从git hub把项目克隆到jenkins slave pod的工作目录/home/jenkins/agent/workspace/pipeline-name
2、测试
3、使用Dockerfile构建镜像
4、把构建的镜像push到docker hub上
5、修改yaml文件中的镜像名为刚才构建的镜像
6、在k8s集群中部署应用
以上步骤的代码可以在jenkins master的任务配置界面输入,也可以写入Jenkinsfile文件在项目源码库中管理
前4步属于CI阶段,最后两步属于CD阶段
Jenkins Pipeline 有几个核心概念:
Node:节点,一个 Node 就是一个 Jenkins 节点,Master 或者 slave
Stage:阶段,一个 Pipeline 可以划分为若干个 Stage,每个 Stage 代表一组操作
Step:步骤,Step 是最基本的操作单元,可以是打印一句话,也可以是构建一个 Docker 镜像
用jenkins代码模拟CI/CD步骤
新建任务----名字----流水线
在流水线脚本中输入如下内容----保存立即构建
node('dongyali-jnlp') { stage('Clone') { echo "1.Clone Stage" } stage('Test') { echo "2.Test Stage" } stage('Build') { echo "3.Build Docker Image Stage" } stage('Push') { echo "4.Push Docker Image Stage" } stage('YAML') { echo "5. Change YAML File Stage" } stage('Deploy') { echo "6. Deploy Stage" }}
假设项目nginx-demo已经开发完毕,并上传到了git hub上
文件包括:
Dockerkfile k8s.yaml index.html README.md
k8s.yaml是部署该应用的文件
$ cd nginx-demo/
$ cat Dockerfile
FROM docker.io/nginxMAINTAINER dongyaliADD index.html /usr/share/nginx/html/EXPOSE 80CMD ["nginx", "-g","daemon off;"]
$ cat k8s.yaml
apiVersion: extensions/v1beta1kind: Deploymentmetadata: name: nginx-demo namespace: defaultspec: replicas: 3 template: metadata: labels: app: nginx-demo spec: containers: - image: dongyali521521/nginx-demo: imagePullPolicy: IfNotPresent name: nginx-demo ports: - containerPort: 80---apiVersion: v1kind: Servicemetadata: name: nginx-demo namespace: defaultspec: selector: app: nginx-demo type: NodePort ports: - protocol: TCP port: 80 targetPort: 80 name: myapp-http
如果不指定namespace,默认会把应用部署到k8s集群的kube-ops空间,因为jenkins slave pod运行在kube-ops空间内。
下面开始在jenkins中部署上述项目:
因为每次git commit之后都要构建镜像重新部署应用,所以采用git commit的记录作为镜像的 tag
为了安全,把构建的镜像push到docker hub上时,需要输入加密的用户名和密码
凭据----Stores scoped to Jenkin下面的Jenkins----全局凭据----添加凭据:
用户名:docker hub的用户名
密码:输入docker hub的用户密码
ID:dockerHub,可以随便写,后面要用
在CD阶段开始之前需要人工干预,以便于部署到用户选择的环境
http://192.168.1.243:30003
新建任务----名字----流水线
在流水线脚本中输入如下内容----保存立即构建
node('dongyali-jnlp') { stage('Clone') { echo "1.Clone Stage" git url: "https://github.com/dongyali521521/nginx-demo.git" script { build_tag = sh(returnStdout: true, script: 'git rev-parse --short HEAD').trim() } } stage('Test') { echo "2.Test Stage" } stage('Build') { echo "3.Build Docker Image Stage" sh "docker build -t dongyali521521/nginx-demo:${build_tag} ." } stage('Push') { echo "4.Push Docker Image Stage" withCredentials([usernamePassword(credentialsId: 'dockerHub', passwordVariable: 'dockerHubPassword', usernameVariable: 'dockerHubUser')]) { sh "docker login -u ${dockerHubUser} -p ${dockerHubPassword}" sh "docker push dongyali521521/nginx-demo:${build_tag}" } } stage('Deploy') { echo "5. Deploy Stage" def userInput = input( id: 'userInput', message: 'Choose a deploy environment', parameters: [ [ $class: 'ChoiceParameterDefinition', choices: "Dev\nQA\nProd", name: 'Env' ] ] ) echo "This is a deploy step to ${userInput}" sh "sed -i 's//${build_tag}/' k8s.yaml" if (userInput == "Dev") { // deploy dev stuff } else if (userInput == "QA"){ // deploy qa stuff } else { // deploy prod stuff } sh "kubectl apply -f k8s.yaml --record" }}
每次构建,都会启动一个新的jenkins slave pod
查看部署情况:
$ kubectl get pod
nginx-demo-65f6f679c6-5ljvd 1/1 Running 0 34m
nginx-demo-65f6f679c6-p4g6m 1/1 Running 0 34m
nginx-demo-65f6f679c6-xr7mx 1/1 Running 0 34m
$ kubectl get svc
nginx-demo NodePort 10.103.13.141
http://http://192.168.1.243:30185/
下面再使用jenkinsfile文件来部署应用
在项目目录nginx-demo下增加一个Jenkinsfile文件,并上传到git hub上
$ cd nginx-demo/
$ cat Jenkinsfile
node('dongyali-jnlp') { stage('Prepare') { echo "1.Prepare Stage" checkout scm script { build_tag = sh(returnStdout: true, script: 'git rev-parse --short HEAD').trim() } } stage('Test') { echo "2.Test Stage" } stage('Build') { echo "3.Build Docker Image Stage" sh "docker build -t dongyali521521/nginx-demo:${build_tag} ." } stage('Push') { echo "4.Push Docker Image Stage" withCredentials([usernamePassword(credentialsId: 'dockerHub', passwordVariable: 'dockerHubPassword', usernameVariable: 'dockerHubUser')]) { sh "docker login -u ${dockerHubUser} -p ${dockerHubPassword}" sh "docker push dongyali521521/nginx-demo:${build_tag}" } } stage('Deploy') { echo "5. Deploy Stage" def userInput = input( id: 'userInput', message: 'Choose a deploy environment', parameters: [ [ $class: 'ChoiceParameterDefinition', choices: "Dev\nQA\nProd", name: 'Env' ] ] ) echo "This is a deploy step to ${userInput}" sh "sed -i 's//${build_tag}/' k8s.yaml" if (userInput == "Dev") { // deploy dev stuff } else if (userInput == "QA"){ // deploy qa stuff } else { // deploy prod stuff } sh "kubectl apply -f k8s.yaml --record" }}
由于Jenkinsfile和其他代码都在git hub源码库中,所以第一步就不需要再clone了,改为checkout scm
然后在jenkins配置任务界面选择:
流水线----pipeline脚本from SCM
SCM:git
Repository URL:https://github.com/dongyali521521/nginx-demo
Credentials:无
保存构建即可。
再测试一个项目
$ git clone https://github.com/dongyali521521/jenkins-demo.git
$ cd jenkins-demo
$ ls
Dockerfile k8s.yaml main.go README.md
$ cat Dockerfile
FROM golang:1.8.0-alpineADD . /go/src/appWORKDIR /go/src/appRUN GOOS=linux GOARCH=386 go build -v -o /go/src/app/jenkins-appCMD ["./jenkins-app"]
$ cat main.go
package main// Import the fmt for formatting strings// Import os so we can read environment variables from the systemimport ( "fmt" "os")func main() { fmt.Println("Hello, Kubernetes!I'm from Jenkins CI!4444") fmt.Println("BRANCH_NAME:", os.Getenv("branch"))}
$ cat k8s.yaml
apiVersion: extensions/v1beta1kind: Deploymentmetadata: name: jenkins-demo namespace: defaultspec: template: metadata: labels: app: jenkins-demo spec: containers: - image: dongyali521521/jenkins-demo: imagePullPolicy: IfNotPresent name: jenkins-demo env: - name: branch value:
$ git add .
$ git commit -m "4444"
$ git push
新建任务----名字----流水线
在流水线脚本中输入如下内容----保存立即构建
node('dongyali-jnlp') { stage('Clone') { echo "1.Clone Stage" git url: "https://github.com/dongyali521521/jenkins-demo.git" script { build_tag = sh(returnStdout: true, script: 'git rev-parse --short HEAD').trim() } } stage('Test') { echo "2.Test Stage" } stage('Build') { echo "3.Build Docker Image Stage" sh "docker build -t dongyali521521/jenkins-demo:${build_tag} ." } stage('Push') { echo "4.Push Docker Image Stage" withCredentials([usernamePassword(credentialsId: 'dockerHub', passwordVariable: 'dockerHubPassword', usernameVariable: 'dockerHubUser')]) { sh "docker login -u ${dockerHubUser} -p ${dockerHubPassword}" sh "docker push dongyali521521/jenkins-demo:${build_tag}" } } stage('Deploy') { echo "5. Deploy Stage" def userInput = input( id: 'userInput', message: 'Choose a deploy environment', parameters: [ [ $class: 'ChoiceParameterDefinition', choices: "Dev\nQA\nProd", name: 'Env' ] ] ) echo "This is a deploy step to ${userInput}" sh "sed -i 's//${build_tag}/' k8s.yaml" if (userInput == "Dev") { // deploy dev stuff } else if (userInput == "QA"){ // deploy qa stuff } else { // deploy prod stuff } sh "kubectl apply -f k8s.yaml --record" }}
$ kubectl get pod
jenkins-demo-67db45cf6c-mjdl4 0/1 CrashLoopBackOff 3 65s
$ kubectl logs jenkins-demo-67db45cf6c-mjdl4
Hello, Kubernetes!I'm from Jenkins CI!4444
BRANCH_NAME: