How to run one-time run command and get result about kubectl-debug

[DavadDi]

kubectl-debug pod_name -- /bin/sh -c "sleep 2 && ls -hl"

It works.
Because sleep 2 extends the lifecycle of the container, giving the chance to the attach cmd catch the container output when it runs a very short task.

[aylei]

@DavadDi Nice catch! I will investigate how to guarantee the output stream being flushed before the debug container get terminated.

Also, the log without verbosity control concerns me, which adds complexity for automation process to parse the output of executed command. I will file another issue for this.

[Fly-Luck]

A good approach with sleep, but if you execute kubectl debug via code(e.g. exec.Command in golang), you cannot get the one-time command's output according to my experience.

One approach I came up with is:

1. modify the netshoot image with an additional volume.
2. sleep 2 && cmd > file in that volume.

Any better idea? @aylei

[yangxikun]

A little ideat: use sleep infinity command to create debug container, then send user cmd(ls -hl) to stdin after attach, otherwise send the default cmd sh to stdin.