Identify in wich container runs a process?

1

Hi
I have identified from the host a process by its PID. How to easily determine in which container it is running?

I know “ps fauxww”, or even looping each CT+ps -ef + filtering, but I’d prefer something more efficient.

Same question if I have identified a or several process by their user ID. How to identify to which container this user ID belongs to ?

Happy New Year!

2

You could try to guess from the cgroup in /proc/PID/cgroup

3

Brilliant. Thank you!

4

would be nice to have such a thing directly available in the lxc command like

  • lxc pidinfo list <container>
  • lxc pidinfo getcontainer <pid>

Would it be worth to create a ticket in github?

At the moment I use custom bash functions like

lxc_get_container_pids(){
    CONTAINER=$1
    find /sys/fs/cgroup/lxc.payload.${CONTAINER}/ -name cgroup.procs -exec cat {} \;
}

lxc_get_container_by_pid(){
    PID=$1
    cat /proc/${PID}/cgroup|awk -F '/' '{ split($2,a,".");print a[3] }'
}

Maybe related to systemd-cgtop and lxc-top for one or more lxd hosts #822

2 Likes