CoreOS - get docker container name by PID?

Question

I have a list of PID's and I need to get their docker container name. Going the other direction is easy ... get PID of docker container by image name:

$ docker inspect --format '{{.State.Pid}}' {SOME DOCKER NAME}

Any idea how to get the name by PID?

Solution 1

Something like this?

$ docker ps -q | xargs docker inspect --format '{{.State.Pid}}, {{.ID}}' | grep "^${PID},"

[EDIT]

Disclaimer This is for "normal" linux. I don't know anything useful about CoreOS, so this may or may not work there.

Solution 2

Because @Mitar's comment suggestion deserves to be a full answer:

To get container ID you can use:

cat /proc/<process-pid>/cgroup

Then to convert the container ID to docker container name:

docker inspect --format '{{.Name}}' "${containerId}" | sed 's/^\///'

Solution 3

I use the following script to get the container name for any host PID of a process inside a container:

#!/bin/bash -e
# Prints the name of the container inside which the process with a PID on the host is.

function getName {
  local pid="$1"

  if [[ -z "$pid" ]]; then
    echo "Missing host PID argument."
    exit 1
  fi

  if [ "$pid" -eq "1" ]; then
    echo "Unable to resolve host PID to a container name."
    exit 2
  fi

  # ps returns values potentially padded with spaces, so we pass them as they are without quoting.
  local parentPid="$(ps -o ppid= -p $pid)"
  local containerId="$(ps -o args= -f -p $parentPid | grep docker-containerd-shim | cut -d ' ' -f 2)"

  if [[ -n "$containerId" ]]; then
    local containerName="$(docker inspect --format '{{.Name}}' "$containerId" | sed 's/^\///')"
    if [[ -n "$containerName" ]]; then
      echo "$containerName"
    else
      echo "$containerId"
    fi
  else
    getName "$parentPid"
  fi
}

getName "$1"

Solution 4

... as a one-liner as well

PID=20168; sudo docker ps --no-trunc | grep $(cat /proc/$PID/cgroup | grep -oE '[0-9a-f]{64}' | head -1) | sed 's/^.* //'

View more solutions

Comments

[Nimrod007]

if only docker name needed can add | awk '{print $2}' in the end :) thanks

[David]

For my current docker version I had to change {{.ID}} to {{.Id}}, seems the docker inspect output has changed slightly!

[Mitar]

Which version of Docker are you using?

[Mitar]

You can also use cat /proc/<host pid>/cgroup to get container ID, and then use docker inspect --format '{{.Name}}' "$containerId" | sed 's/^\///' to get name from ID.

[Markus Kasten]

As a one-liner, using @Mitar 's idea: docker inspect --format '{{.Name}}' "$(cat /proc/$PID/cgroup |head -n 1 |cut -d / -f 3)" | sed 's/^\///'

[wheeler]

What is the ${PID} in the grep regex do? I just tried this and the grep is not working.

[ivant]

@wheeler, it's the PID you're looking for. For example, if you're looking for PID 123, then you can export PID=123 before running the above command. Or you can just replace ${PID} with 123.

[Ritschie]

or even shorter PID=20168; sudo docker ps --no-trunc | grep $(grep -oE '[0-9a-f]{64}' /proc/$PID/cgroup | head -1) | sed 's/^.* //'

[Ritschie]

or even minimal faster :) sudo docker ps --no-trunc | grep $(head -1 /proc/$PID/cgroup | grep -oE '[0-9a-f]{64}') | sed 's/^.* //' a little explanation: --no-trunc shows the container-id in a 64Bit Hash containing only Numbers and Characters from "a" to "f" grep -oE '[0-9a-f]{64}' greps exactly for a 64 Bit hash and prints out the hash only

[Hoppeduppeanut]

Please don't include additional information to your answer as a comment. Instead, please edit your answer to include this information in the answer itself, using formatted-text.