6.2. 通过定义自定义 SA 和 SCC，以非 root 用户身份运行 Buildah

流程

1. 创建 openshift-pipelines 命名空间中提供的 buildah 任务的副本；将副本的名称更改为 buildah-as-user。

   $ oc get task buildah -n openshift-pipelines -o yaml | yq '. |= (del .metadata |= with_entries(select(.key == "name" )))' | yq '.kind="Task"' | yq '.metadata.name="buildah-as-user"' | oc create -f -

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2. 编辑复制的 buildah 任务。

   $ oc edit task buildah-as-user

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   示例：使用 build 用户修改 Buildah 任务

   apiVersion: tekton.dev/v1
   kind: Task
   metadata:
     name: buildah-as-user
   spec:
     description: >-
       Buildah task builds source into a container image and
       then pushes it to a container registry.
       Buildah Task builds source into a container image using Project Atomic's
       Buildah build tool.It uses Buildah's support for building from Dockerfiles,
       using its buildah bud command.This command executes the directives in the
       Dockerfile to assemble a container image, then pushes that image to a
       container registry.
     params:
     - name: IMAGE
       description: Reference of the image buildah will produce.
     - name: BUILDER_IMAGE
       description: The location of the buildah builder image.
       default: registry.redhat.io/rhel8/buildah@sha256:99cae35f40c7ec050fed3765b2b27e0b8bbea2aa2da7c16408e2ca13c60ff8ee
     - name: STORAGE_DRIVER
       description: Set buildah storage driver
       default: vfs
     - name: DOCKERFILE
       description: Path to the Dockerfile to build.
       default: ./Dockerfile
     - name: CONTEXT
       description: Path to the directory to use as context.
       default: .
     - name: TLSVERIFY
       description: Verify the TLS on the registry endpoint (for push/pull to a non-TLS registry)
       default: "true"
     - name: FORMAT
       description: The format of the built container, oci or docker
       default: "oci"
     - name: BUILD_EXTRA_ARGS
       description: Extra parameters passed for the build command when building images.
       default: ""
     - description: Extra parameters passed for the push command when pushing images.
       name: PUSH_EXTRA_ARGS
       type: string
       default: ""
     - description: Skip pushing the built image
       name: SKIP_PUSH
       type: string
       default: "false"
     results:
     - description: Digest of the image just built.
       name: IMAGE_DIGEST
       type: string
     workspaces:
     - name: source
     steps:
     - name: build
       securityContext:
         runAsUser: 1000 

   1

   
       image: $(params.BUILDER_IMAGE)
       workingDir: $(workspaces.source.path)
       script: |
         echo "Running as USER ID `id`" 

   2

   
         buildah --storage-driver=$(params.STORAGE_DRIVER) bud \
           $(params.BUILD_EXTRA_ARGS) --format=$(params.FORMAT) \
           --tls-verify=$(params.TLSVERIFY) --no-cache \
           -f $(params.DOCKERFILE) -t $(params.IMAGE) $(params.CONTEXT)
         [[ "$(params.SKIP_PUSH)" == "true" ]] && echo "Push skipped" && exit 0
         buildah --storage-driver=$(params.STORAGE_DRIVER) push \
           $(params.PUSH_EXTRA_ARGS) --tls-verify=$(params.TLSVERIFY) \
           --digestfile $(workspaces.source.path)/image-digest $(params.IMAGE) \
           docker://$(params.IMAGE)
         cat $(workspaces.source.path)/image-digest | tee /tekton/results/IMAGE_DIGEST
       volumeMounts:
       - name: varlibcontainers
         mountPath: /home/build/.local/share/containers 

   3

   
     volumes:
     - name: varlibcontainers
       emptyDir: {}

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   1

   以用户 id 1000 明确运行容器，它与 Buildah 镜像中的 build 用户对应。

   2

   显示用户 id，以确认进程以用户 ID 1000 身份运行。

   3

   您可以根据需要更改卷挂载的路径。

流程

1. 使用自定义 ConfigMap 和 Dockerfile 对象创建一个 TaskRun 对象。

   示例：以用户 ID 1000 身份运行 Buildah 的任务运行

   apiVersion: v1
   data:
     Dockerfile: |
       ARG BASE_IMG=registry.access.redhat.com/ubi9/ubi
       FROM $BASE_IMG AS buildah-runner
       RUN dnf -y update && \
           dnf -y install git && \
           dnf clean all
       CMD git
   kind: ConfigMap
   metadata:
     name: dockerfile 

   1

   
   ---
   apiVersion: tekton.dev/v1
   kind: TaskRun
   metadata:
     name: buildah-as-user-1000
   spec:
     taskRunTemplate:
       serviceAccountName: pipelines-sa-userid-1000 

   2

   
     params:
     - name: IMAGE
       value: image-registry.openshift-image-registry.svc:5000/test/buildahuser
     taskRef:
       kind: Task
       name: buildah-as-user
     workspaces:
     - configMap:
         name: dockerfile 

   3

   
       name: source

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   1

   使用配置映射，因为重点是在任务运行中，而无需使用 Dockerfile 获取某些源的以前的任务。

   2

   您创建的服务帐户的名称。

   3

   将配置映射挂载为 buildah-as-user 任务的源工作区。

2. （可选）创建管道和对应的管道运行。

   示例：管道和对应的管道运行

   apiVersion: tekton.dev/v1
   kind: Pipeline
   metadata:
     name: pipeline-buildah-as-user-1000
   spec:
     params:
     - name: IMAGE
     - name: URL
     workspaces:
     - name: shared-workspace
     - name: sslcertdir
       optional: true
     tasks:
     - name: fetch-repository 

   1

   
       taskRef:
         resolver: cluster
         params:
         - name: kind
           value: task
         - name: name
           value: git-clone
         - name: namespace
           value: openshift-pipelines
       workspaces:
       - name: output
         workspace: shared-workspace
       params:
       - name: URL
         value: $(params.URL)
       - name: SUBDIRECTORY
         value: ""
       - name: DELETE_EXISTING
         value: "true"
     - name: buildah
       taskRef:
         name: buildah-as-user 

   2

   
       runAfter:
       - fetch-repository
       workspaces:
       - name: source
         workspace: shared-workspace
       - name: sslcertdir
         workspace: sslcertdir
       params:
       - name: IMAGE
         value: $(params.IMAGE)
   ---
   apiVersion: tekton.dev/v1
   kind: PipelineRun
   metadata:
     name: pipelinerun-buildah-as-user-1000
   spec:
     taskRunSpecs:
       - pipelineTaskName: buildah
         taskServiceAccountName: pipelines-sa-userid-1000 

   3

   
     params:
     - name: URL
       value: https://github.com/openshift/pipelines-vote-api
     - name: IMAGE
       value: image-registry.openshift-image-registry.svc:5000/test/buildahuser
     pipelineRef:
       name: pipeline-buildah-as-user-1000
     workspaces:
     - name: shared-workspace 

   4

   
       volumeClaimTemplate:
         spec:
           accessModes:
             - ReadWriteOnce
           resources:
             requests:
               storage: 100Mi

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   1

   使用 git-clone 任务获取包含 Dockerfile 的源，并使用修改后的 Buildah 任务构建它。

   2

   请参阅修改后的 Buildah 任务。

   3

   使用您为 Buildah 任务创建的服务帐户。

   4

   使用控制器自动创建的持久性卷声明 (PVC) 在 git-clone 任务和修改后的 Buildah 任务间共享数据。

3. 启动任务运行或管道运行。