20.3. 使用 buildah mount 修改容器

流程

1. 创建一个基于 registry.access.redhat.com/ubi8/ubi 镜像的可工作容器，并将容器名称保存到 mycontainer 变量中：

   # mycontainer=$(buildah from localhost/myecho)
   
   # echo $mycontainer
   myecho-working-container

2. 挂载 myecho-working-container 容器，并将挂载点路径保存到 mymount 变量中：

   # mymount=$(buildah mount $mycontainer)
   
   # echo $mymount
   /var/lib/containers/storage/overlay/c1709df40031dda7c49e93575d9c8eebcaa5d8129033a58e5b6a95019684cc25/merged

3. 修改 myecho 脚本并使其可执行：

   # echo 'echo "We modified this container."' >> $mymount/usr/local/bin/myecho
   # chmod +x $mymount/usr/local/bin/myecho

4. 从 myecho-working-container 容器创建 myecho2 镜像：

   # buildah commit $mycontainer containers-storage:myecho2

验证

1. 列出本地存储中的所有镜像：

   # buildah images
   REPOSITORY                                  TAG      IMAGE ID       CREATED          SIZE
   docker.io/library/myecho2                   latest   4547d2c3e436   4 minutes ago    234 MB
   localhost/myecho                            latest   b28cd00741b3   56 minutes ago   234 MB

2. 运行基于 docker.io/library/myecho2 镜像的 myecho2 容器：

   # podman run --name=myecho2 docker.io/library/myecho2
   This container works!
   We even modified it.