kubectl cp 容器文件到本地报错tar: Removing leading `/‘ from member names

kubectl cp 容器文件到本地
首先看下帮助命令：

kubectl cp --help
Copy files and directories to and from containers.

Examples:
  # !!!Important Note!!!
  # Requires that the 'tar' binary is present in your container
  # image.  If 'tar' is not present, 'kubectl cp' will fail.
  #
  # For advanced use cases, such as symlinks, wildcard expansion or
  # file mode preservation, consider using 'kubectl exec'.
  
  # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace 
  tar cf - /tmp/foo | kubectl exec -i -n <some-namespace> <some-pod> -- tar xf - -C /tmp/bar
  
  # Copy /tmp/foo from a remote pod to /tmp/bar locally
  kubectl exec -n <some-namespace> <some-pod> -- tar cf - /tmp/foo | tar xf - -C /tmp/bar
  
  # Copy /tmp/foo_dir local directory to /tmp/bar_dir in a remote pod in the default namespace
  kubectl cp /tmp/foo_dir <some-pod>:/tmp/bar_dir
  
  # Copy /tmp/foo local file to /tmp/bar in a remote pod in a specific container
  kubectl cp /tmp/foo <some-pod>:/tmp/bar -c <specific-container>
  
  # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace 
  kubectl cp /tmp/foo <some-namespace>/<some-pod>:/tmp/bar
  
  # Copy /tmp/foo from a remote pod to /tmp/bar locally
  kubectl cp <some-namespace>/<some-pod>:/tmp/foo /tmp/bar

Options:
    -c, --container='':
        Container name. If omitted, use the kubectl.kubernetes.io/default-container annotation for selecting the
        container to be attached or the first container in the pod will be chosen

    --no-preserve=false:
        The copied file/directory's ownership and permissions will not be preserved in the container

    --retries=0:
        Set number of retries to complete a copy operation from a container. Specify 0 to disable or any negative
        value for infinite retrying. The default is 0 (no retry).

Usage:
  kubectl cp <file-spec-src> <file-spec-dest> [options]

Use "kubectl options" for a list of global command-line options (applies to all commands).

从帮助命令中可以看到，从pod中cp文件到本地格式为：
#Copy /tmp/foo from a remote pod to /tmp/bar locally

kubectl cp <some-namespace>/<some-pod>:/tmp/foo /tmp/bar

然而发现会报错，不能写文件的完整路径：

#kubectl  cp default/test-5746d4c59f-9c7sm:/docker-entrypoint.sh /tmp/docker-entrypoint.sh
tar: Removing leading `/' from member names

可以看出，cp命令需要将文件压缩再拷回本地，因为 tar 默认将文件路径视为相对路径，而不是绝对路径，所以会报建这个错误。
正确处理方式是,先确认POD容器的工作目录，然后把文件放到工作目录中，cp的时候不需要加’/'就能正常。