6.2. 创建自定义构建工件

流程

1. 从空目录着手，使用以下内容创建名为 Dockerfile 的文件：

   FROM registry.redhat.io/rhel8/buildah
   # In this example, `/tmp/build` contains the inputs that build when this
   # custom builder image is run. Normally the custom builder image fetches
   # this content from some location at build time, by using git clone as an example.
   ADD dockerfile.sample /tmp/input/Dockerfile
   ADD build.sh /usr/bin
   RUN chmod a+x /usr/bin/build.sh
   # /usr/bin/build.sh contains the actual custom build logic that will be run when
   # this custom builder image is run.
   ENTRYPOINT ["/usr/bin/build.sh"]

2. 在同一目录中，创建名为 dockerfile.sample 的文件。此文件将包含在自定义构建镜像中，并且定义将由自定义构建生成的镜像：

   FROM registry.access.redhat.com/ubi8/ubi
   RUN touch /tmp/build

3. 在同一目录中，创建名为 build.sh 的文件。此文件包含自定义生成运行时将要执行的逻辑：

   #!/bin/sh
   # Note that in this case the build inputs are part of the custom builder image, but normally this
   # is retrieved from an external source.
   cd /tmp/input
   # OUTPUT_REGISTRY and OUTPUT_IMAGE are env variables provided by the custom
   # build framework
   TAG="${OUTPUT_REGISTRY}/${OUTPUT_IMAGE}"
   
   
   # performs the build of the new image defined by dockerfile.sample
   buildah --storage-driver vfs bud --isolation chroot -t ${TAG} .
   
   
   # buildah requires a slight modification to the push secret provided by the service
   # account in order to use it for pushing the image
   cp /var/run/secrets/openshift.io/push/.dockercfg /tmp
   (echo "{ \"auths\": " ; cat /var/run/secrets/openshift.io/push/.dockercfg ; echo "}") > /tmp/.dockercfg
   
   
   # push the new image to the target for the build
   buildah --storage-driver vfs push --tls-verify=false --authfile /tmp/.dockercfg ${TAG}