container_pid_to_docker_id.sh

pid=${1:?must provide pid argument}

function getMntns() {
  ls -ali /proc/$1/ns/mnt | sed 's/.*mnt:\[\([0-9]\+\)\].*/\1/'
}

targetns=$(getMntns $pid)

for container in $(docker inspect --format '{{.State.Pid }}-{{ .Id }}' $(docker ps -q)); do 
  cpid=$(echo $container | awk -F- '{print $1}')
  mntns=$(getMntns $cpid)
  if [[ "${mntns}" == "${targetns}" ]]; then
    echo "Found container id: $(echo $container | awk -F- '{print $2}')"
  fi
done