在 Kubernetes 上使用 Tekton 快速实现应用自动发布

Tekton 是一个功能强大且灵活的 Kubernetes 原生开源框架，用于创建持续集成和交付（CI/CD）系统。通过抽象底层实现细节，用户可以跨多云平台和本地系统进行构建、测试和部署。

Tekton 提供的开源组件可以跨供应商，Tekton 提供的管道、版本、工作流程和其他 CI/CD 组件的行业规范一致，可以和你现有的 CI/CD 工具（例如：Jenkins、Jenkins X、Skaffold 和 Knative 等）配合使用。

Tekton 和其它几种 CI/CD 工具的比较

使用 Tekton 的内置最佳实践可以快速创建云原生 CI / CD 管道，目标是让开发人员创建和部署不可变镜像，管理基础架构的版本控制或执行更简单的回滚。还可以利用 Tekton 的滚动部署，蓝 / 绿部署，金丝雀部署或 GitOps 工作流等高级部署模式。

使用 Tekton 可跨多个环境（例如：VM、无服务器、Kubernetes 或 Firebase）进行构建，测试和部署。你还可以使用 Tekton 管道跨多云平台或混合环境进行部署。

Tekton 提供了最大的灵活性，让你可以使用自己喜欢的 CI/CD 工具构建强大的管道。

项目地址：https://github.com/tektoncd/pipeline

下面来看一个基于阿里云 Kubernetes 服务部署 Tekton Pipeline 的实例，部署完成后我们使用它来完成源码拉取、应用打包、镜像推送和应用部署。

Tekton Pipeline 中有 5 类对象，核心理念是通过定义 YAML 定义构建过程，构建任务的状态存放在 status 字段中。

其中 5 类对象分别是：PipelineResouce、Task、TaskRun、Pipeline、PipelineRun。

Task 是单个任务的构建过程，需要通过定义 TaskRun 任务去运行 Task。

Pipeline 包含多个 Task，并在此基础上定义 input 和 output，input 和 output 以 PipelineResource 作为交付。

PipelineResource 是可用于 input 和 output 的对象集合。

同样地,需要定义 PipelineRun 才会运行 Pipeline。

在阿里云 Kubernetes 集群中部署 Tekton Pipeline

1	$ kubectl apply --filename https://storage.googleapis.com/tekton-releases/latest/release.yaml

查看Tekton Pipelines组件是否运行正常：

$ kubectl -n tekton-pipelines get po
NAME                                                     READY   STATUS      RESTARTS   AGE
tekton-pipelines-controller-6bcd7ff5d6-vzmrh             1/1     Running     0          25h
tekton-pipelines-webhook-6856cf9c47-l6nj6                1/1     Running     0          25h

创建 Git Resource 和 Registry Resource

编辑 git-pipeline-resource.yaml 文件

# git repo 的分支名称为 tekton
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: git-pipeline-resource
spec:
  type: git
  params:
    - name: revision
      value: tekton
    - name: url
      value: https://code.aliyun.com/haoshuwei/jenkins-demo.git

编辑 registry-pipeline-resource.yaml 文件

# 容器镜像仓库地址为 registry.cn-hangzhou.aliyuncs.com/haoshuwei/tekton-demo， 标签为 latest
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: registry-pipeline-resource
spec:
  type: image
  params:
    - name: url
      value: registry.cn-hangzhou.aliyuncs.com/haoshuwei/tekton-demo

创建 pipeline resource

1 2	$ kubectl -n tekton-pipelines create -f git-pipeline-resource.yaml $ kubectl -n tekton-pipelines create -f registry-pipeline-resource.yaml

查看已创建的 pipeline resource 资源

$ kubectl -n tekton-pipelines get PipelineResource
NAME                         AGE
git-pipeline-resource        2h
registry-pipeline-resource   2h

创建 Git Repo / Docker Registry Authentication

拉取私有 Git 源码项目需要配置使用 Git Repo Authentication，拉取和推送 Docker 镜像需要配置 Docker Registry Authentication。

在 Tekton Pipeline 中，Git Repo / Docker Registry Authentication 会被定义成ServiceAccount来使用。

编辑 secret tekton-basic-user-pass-git.yaml

apiVersion: v1
kind: Secret
metadata:
  name: tekton-basic-user-pass-git
  annotations:
    tekton.dev/git-0: https://code.aliyun.com
type: kubernetes.io/basic-auth
stringData:
  username: <cleartext non-encoded>
  password: <cleartext non-encoded>

编辑 secret tekton-basic-user-pass-registry.yaml

apiVersion: v1
kind: Secret
metadata:
  name: tekton-basic-user-pass-registry
  annotations:
    tekton.dev/docker-0: https://registry.cn-hangzhou.aliyuncs.com
type: kubernetes.io/basic-auth
stringData:
  username: <cleartext non-encoded>
  password: <cleartext non-encoded>

编辑 serviceaccount tekton-git-and-registry.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: tekton-git-and-registry
secrets:
  - name: tekton-basic-user-pass-git
  - name: tekton-basic-user-pass-registry

创建 serviceaccount

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$ kubectl -n tekton-pipelines create -f tekton-basic-user-pass-git.yaml
$ kubectl -n tekton-pipelines create -f tekton-basic-user-pass-registry.yaml
$ kubectl -n tekton-pipelines create -f tekton-git-and-registry.yaml

查看 secret 以及 sa

$ kubectl -n tekton-pipelines get secret
NAME                                      TYPE                                  DATA   AGE
default-token-pwncj                       kubernetes.io/service-account-token   3      25h
tekton-basic-user-pass-git                kubernetes.io/basic-auth              2      151m
tekton-basic-user-pass-registry           kubernetes.io/basic-auth              2      151m
tekton-git-and-registry-token-tr95m       kubernetes.io/service-account-token   3      151m
tekton-pipelines-controller-token-lc2fv   kubernetes.io/service-account-token   3      25h  
webhook-certs                             Opaque                                3      25h

$  kubectl -n tekton-pipelines get sa
NAME                          SECRETS   AGE
default                       1         25h
tekton-git-and-registry       3         152m
tekton-pipelines-controller   1         25h

配置 serviceaccount

配置一个 tekton-git-and-registry 帐号以获取命名空间 tekton-pipelines 的管理权限，用于部署应用。

创建 ClusterRoleBinding tekton-cluster-admin

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: tekton-cluster-admin
subjects:
  - kind: ServiceAccount
    name: tekton-git-and-registry
    namespace: tekton-pipelines
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io

创建一个 Task

创建 task build-app.yaml

apiVersion: tekton.dev/v1alpha1
kind: Task
metadata:
  name: build-app
spec:
  inputs:
    resources:
      - name: java-demo
        type: git
    params:
      - name: pathToDockerFile
        description: The path to the dockerfile to build
        default: /workspace/java-demo/Dockerfile
      - name: pathToContext
        description: The build context used by Kaniko
        default: /workspace/java-dem
      - name: pathToYaml
        description: The path to teh manifest to apply
  outputs:
    resources:
      - name: builtImage
        type: image
  steps:
    - name: build-mvn-package
      image: registry.cn-beijing.aliyuncs.com/acs-sample/jenkins-slave-maven:3.3.9-jdk-8-alpine
      workingDir: /workspace/java-demo
      command:
        - mvn
      args:
        - package
        - -B
        - -DskipTests
    - name: build-docker-image
      image: registry.cn-beijing.aliyuncs.com/acs-sample/jenkins-slave-kaniko:0.6.0
      command:
        - kaniko
      args:
        - --dockerfile=${inputs.params.pathToDockerFile}
        - --destination=${outputs.resources.builtImage.url}
        - --context=${inputs.params.pathToContext}
    - name: deploy-app
      image: registry.cn-beijing.aliyuncs.com/acs-sample/jenkins-slave-kubectl:1.11.5
      command:
        - kubectl
      args:
        - apply
        - -f
        - ${inputs.params.pathToYaml}

创建 TaskRun 运行任务

创建 taskrun build-app-task-run.yaml

apiVersion: tekton.dev/v1alpha1
kind: TaskRun
metadata:
  name: build-app-task-run
spec:
  serviceAccount: tekton-git-and-registry
  taskRef:
    name: build-app
  trigger:
    type: manual
  inputs:
    resources:
      - name: java-demo
        resourceRef:
          name: git-pipeline-resource
    params:
      - name: pathToDockerFile
        value: Dockerfile
      - name: pathToContext
        value: /workspace/java-demo
      - name: pathToYaml
        value: /workspace/java-demo/deployment.yaml
  outputs:
    resources:
      - name: builtImage
        resourceRef:
          name: registry-pipeline-resource

查看构建状态以及日志

查看 taskrun 状态

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$ kubectl -n tekton-pipelines get taskrun
NAME                 SUCCEEDED   REASON    STARTTIME   COMPLETIONTIME
build-app-task-run   Unknown     Pending   4s

查看构建日志

$ kubectl -n tekton-pipelines get po
NAME                                           READY   STATUS    RESTARTS   AGE
build-app-task-run-pod-b8f890                  3/5     Running   0          75s
tekton-pipelines-controller-6bcd7ff5d6-vzmrh   1/1     Running   0          25h
tekton-pipelines-webhook-6856cf9c47-l6nj6      1/1     Running   0          25h

$ kubectl -n tekton-pipelines logs -f build-app-task-run-pod-b8f890
Error from server (BadRequest): a container name must be specified for pod build-app-task-run-pod-b8f890, choose one of:   [build-step-git-source-git-pipeline-resource-77l5v build-step-build-mvn-package build-step-build-docker-image build-step-deploy-app nop] or one of the init containers: [build-step-credential-initializer-8dsnm build-step-place-tools]

MVN Build 的日志

$ kubectl -n tekton-pipelines logs -f build-app-task-run-pod-b8f890 -c build-step-build-mvn-package
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building jenkins-demo-web 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.6/maven-resources-plugin-2.6.pom
[INFO] Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.6/maven-resources-plugin-2.6.pom (8 KB at 7.3 KB/sec)
[INFO] Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/23/maven-plugins-23.pom
[INFO] Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/23/maven-plugins-23.pom (9 KB at 26.7 KB/sec)
[INFO] Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/maven-parent/22/maven-parent-22.pom
[INFO] Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/maven-parent/22/maven-parent-22.pom (30 KB at 61.3 KB/sec)
[INFO] Downloading: https://repo.maven.apache.org/maven2/org/apache/apache/11/apache-11.pom
[INFO] Downloaded: https://repo.maven.apache.org/maven2/org/apache/apache/11/apache-11.pom (15 KB at 45.3 KB/sec)
....

Docker Build 的日志

$ kubectl -n tekton-pipelines logs -f build-app-task-run-pod-b8f890 -c build-step-build-docker-image
INFO[0000] Downloading base image tomcat
2019/05/06 11:58:46 No matching credentials were found, falling back on anonymous
INFO[0003] Taking snapshot of full filesystem...
INFO[0003] Skipping paths under /builder/home, as it is a whitelisted directory
INFO[0003] Skipping paths under /builder/tools, as it is a whitelisted directory
INFO[0003] Skipping paths under /dev, as it is a whitelisted directory
INFO[0003] Skipping paths under /kaniko, as it is a whitelisted directory
INFO[0003] Skipping paths under /proc, as it is a whitelisted directory
INFO[0003] Skipping paths under /run/secrets/kubernetes.io/serviceaccount, as it is a whitelisted directory
INFO[0003] Skipping paths under /sys, as it is a whitelisted directory
INFO[0003] Skipping paths under /var/run, as it is a whitelisted directory
INFO[0003] Skipping paths under /workspace, as it is a whitelisted directory
INFO[0003] Using files from context: [/workspace/java-demo/target/demo.war]
INFO[0003] ADD target/demo.war /usr/local/tomcat/webapps/demo.war
INFO[0003] Taking snapshot of files...
...

app-deploy 的日志

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$ kubectl -n tekton-pipelines logs -f build-app-task-run-pod-637855 -c build-step-deploy-app
deployment.extensions/jenkins-java-demo created
service/jenkins-java-demo created

taskrun 的完成状态为 True 则构建部署过程完成

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$ kubectl -n tekton-pipelines get taskrun
NAME                 SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
build-app-task-run   True                 4m          2m

小结

Tekton Pipeline 中的任务模板可以拿来复用，而不需要重复定义，另外通过 CRD 重新定义 CI/CD 是一大亮点。