CICD联动阿里云容器服务Kubernetes实践之GitLab CI篇（一）

本文档以构建一个 Java 软件项目并部署到 阿里云容器服务的Kubernetes集群 为例说明如何使用 GitLab CI在阿里云Kubernetes服务上运行GitLab-Runner、配置kubernetes类型的executor并执行Pipeline。

1. 创建GitLab源码项目并上传示例代码

1.1 创建GitLab源码项目

本示例中创建的GitLab源码项目地址为：

http://xx.xx.xx.xx/demo/gitlab-java-demo.git

1.2 获取示例代码并上传至GitLab

$ git clone https://code.aliyun.com/CodePipeline/gitlabci-java-demo.git
$ git remote add gitlab http://xx.xx.xx.xx/demo/gitlab-java-demo.git
$ git push gitlab master

2. 在Kubernetes集群中安装GitLab-Runner

2.1 获取GitLab Runner的注册信息

2.1.1 项目专用Runner

Project --> Settings --> CI/CD --> Runners， 获取URL和registration token信息，如图：

2.1.2 Group Runners

Group --> Settings --> CI/CD --> Runners， 获取URL和registration token信息，如图：

2.1.3 Shared Runners

只能管理员创建， 进入admin/runners 页面获取url和token

2.2 获取并修改GitLab Runner的Helm Chart

$ git clone https://github.com/haoshuwei/ack-gitlab-runner.git

修改values.yaml文件, 示例如下：

## GitLab Runner Image
##
image: gitlab/gitlab-runner:alpine-v12.1.0

## Specify a imagePullPolicy
##
imagePullPolicy: IfNotPresent

## Default container image to use for initcontainer
init:
  image: busybox
  tag: latest

## The GitLab Server URL (with protocol) that want to register the runner against
##
gitlabUrl: http://xx.xx.xx.xx/

## The Registration Token for adding new Runners to the GitLab Server. This must
## be retreived from your GitLab Instance.
##
runnerRegistrationToken: "AMvEWrBTBu-d8czEYyfY"
## Unregister all runners before termination
##
unregisterRunners: true
  
## Configure the maximum number of concurrent jobs
##
concurrent: 10
  
## Defines in seconds how often to check GitLab for a new builds
##
checkInterval: 30
  
## For RBAC support:
##
rbac:
  create: true
  clusterWideAccess: false
    
## Configure integrated Prometheus metrics exporter
##
metrics:
  enabled: true
    
## Configuration for the Pods that that the runner launches for each new job
##
runners:
  ## Default container image to use for builds when none is specified
  ##
  image: ubuntu:16.04
  
  ## Specify the tags associated with the runner. Comma-separated list of tags.
  ##
  tags: "k8s-runner"
    
  ## Run all containers with the privileged flag enabled
  ## This will allow the docker:dind image to run if you need to run Docker
  ## commands. Please read the docs before turning this on:
  ##
  privileged: true
    
  ## Namespace to run Kubernetes jobs in (defaults to the same namespace of this release)
  ##
  namespace: gitlab
    
  cachePath: "/opt/cache"
    
  cache: {}
  builds: {}
  services: {}
  helpers: {}
  
resources: {}

2.3 安装GitLab Runner

$ helm package .
Successfully packaged chart and saved it to: /root/ack-gitlab-runner/ack-gitlab-runner-0.1.37.tgz
  
$ helm install --namespace gitlab --name gitlab-runner *.tgz

查看相关的deployment/pod启动是否成功，若成功启动， 则在GitLab上可以看到注册成功的GitLab Runner， 如图：

3. 缓存cache的配置

GitLab Runner中对缓存方案的支持有限，所以我们使用挂载volume的方式做缓存。在上面的示例中， 我们在安装GitLab Runner时默认使用/opt/cache目录作为缓存空间（可以修改values.yaml文件中的runners.cachePath字段）

比如建立maven缓存， 可以在variables下添加MAVEN_OPTS变量并指定本地缓存目录：

variables:
  KUBECONFIG: /etc/deploy/config
  MAVEN_OPTS: "-Dmaven.repo.local=/opt/cache/.m2/repository"

如果需要挂载新的volume， 则可以修改templates/configmap.yaml文件中的如下字段：

cat >>/home/gitlab-runner/.gitlab-runner/config.toml <<EOF
            [[runners.kubernetes.volumes.pvc]]
              name = "gitlab-runner-cache"
              mount_path = "{{ .Values.runners.cachePath }}"
EOF

即在GitLab Runner进行register之后， 在run之前， 修改config.toml的配置。

4. 全局变量的设置

Project --> Settings --> CI/CD --> Variables， 添加GitLab Runner可用的环境变量，本示例添加3个变量如下：

• REGISTRY_USERNAME 镜像仓库用户名
• REGISTRY_PASSWORD 镜像仓库密码
• kube_config kubeconfig的编码字符串

kubeconfig的编码字符串的生成：

echo $(cat ~/.kube/config | base64) | tr -d " "

5. 编写.gitlab-ci.yml

编写.gitlab-ci.yml文件完成java demo源码项目的编译构建、镜像推送和应用部署。（可参考gitlabci-java-demo源码项目中的.gitlab-ci.yml.example）

.gitlab-ci.yml示例：

image: docker:stable
stages:
  - package
  - docker_build
  - deploy_k8s
variables:
  KUBECONFIG: /etc/deploy/config
mvn_build_job:
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20
  stage: package
  tags:
    - k8s-runner
  script:
    - mvn package -B -DskipTests
    - cp target/demo.war /opt/cache
docker_build_job:
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20
  stage: docker_build
  tags:
    - k8s-runner
  script:
    - docker login -u $REGISTRY_USERNAME -p $REGISTRY_PASSWORD registry.cn-beijing.aliyuncs.com
    - mkdir target
    - cp /opt/cache/demo.war target/demo.war
    - docker build -t registry.cn-beijing.aliyuncs.com/gitlab-demo/java-demo:$CI_PIPELINE_ID .
    - docker push registry.cn-beijing.aliyuncs.com/gitlab-demo/java-demo:$CI_PIPELINE_ID
deploy_k8s_job:
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20
  stage: deploy_k8s
  tags:
    - k8s-runner
  script:
    - mkdir -p /etc/deploy
    - echo $kube_config |base64 -d > $KUBECONFIG
    - sed -i "s/IMAGE_TAG/$CI_PIPELINE_ID/g" deployment.yaml
    - cat deployment.yaml
    - kubectl apply -f deployment.yaml

.gitlab-ci.yml定义了一个Pipeline， 分三个阶段步骤执行：

image: docker:stable  # Pipeline中各个步骤阶段的构建镜像没有指定时， 默认使用docker:stable镜像
stages:
  - package                # 源码打包阶段
  - docker_build         # 镜像构建和打包阶段
  - deploy_k8s           # 应用部署阶段
variables:
  KUBECONFIG: /etc/deploy/config   # 定义全局变量KUBECONFIG

maven源码打包阶段：

mvn_build_job:     # job名称
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20  # 本阶段构建使用的构建镜像
  stage: package      # 关联的阶段名称
  tags:                     # GitLab Runner的tag
    - k8s-runner
  script:
    - mvn package -B -DskipTests  # 执行构建脚本
    - cp target/demo.war /opt/cache   # 构建物保存至缓存区

镜像构建和发布阶段：

docker_build_job:  # job名称, 已挂载docker.sock
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20 # 本阶段构建使用的构建镜像
  tags:                      # GitLab Runner的tag
    - k8s-runner
  script:
    - docker login -u REGISTRY_USERNAME -p $REGISTRY_PASSWORD registry.cn-beijing.aliyuncs.com   # 登录镜像仓库
    - mkdir target
    - cp /opt/cache/demo.war target/demo.war
    - docker build -t registry.cn-beijing.aliyuncs.com/gitlab-demo/java-demo:$CI_PIPELINE_ID .     # 打包docker镜像，使用的tag为本次pipeline的id
    - docker push registry.cn-beijing.aliyuncs.com/gitlab-demo/java-demo:$CI_PIPELINE_ID      # 推送docker镜像

应用部署阶段：

deploy_k8s_job:   # job名称
  image: registry.cn-beijing.aliyuncs.com/codepipeline/public-blueocean-codepipeline-slave-java:0.1-63b99a20   # 本阶段构建使用的构建镜像
  stage: deploy_k8s   # 关联的阶段名称
  tags:                      # GitLab Runner的tag
    - k8s-runner
  script:
    - mkdir -p /etc/deploy
    - echo $kube_config |base64 -d > $KUBECONFIG   # 配置连接Kubernetes集群的config文件
    - sed -i "s/IMAGE_TAG/$CI_PIPELINE_ID/g" deployment.yaml  # 动态替换部署文件中的镜像tag
    - kubectl apply -f deployment.yaml

6. 执行pipeline

提交.gitlab-ci.yml文件后，Project gitlab-java-demo会自动检测到这个文件并自行pipeline， 如图：

7. 访问服务

如果部署文件中没有指定namespace， 则默认会部署到gitlab命名空间下：

$ kubectl -n gitlab get svc 
NAME        TYPE           CLUSTER-IP     EXTERNAL-IP      PORT(S)        AGE
java-demo   LoadBalancer   172.19.9.252   xx.xx.xx.xx   80:32349/TCP   1m

浏览器访问 xx.xx.xx.xx/demo 进行验证

了解更多阿里云容器服务内容，请访问 https://www.aliyun.com/product/containerservice
了解更多GitLab CI的内容，请访问 https://docs.gitlab.com/runner/