CODEWITHSUNDEEP
docker
Alexcei Shmakov
Alexcei Shmakov

Reputation: 2343

docker find container by pid of inside process

I have docker containers. Inside them launched a process. From the host machine the command top outputs pid of all processes launched in within containers.

How can I find a container in which the process with this PID is running?

Thank you.

Upvotes: 26

Views: 31744

Answers (6)

Emre
Emre

Reputation: 21

I kinda combined all of these and wrote this two liner. Hopefully useful to someone.

#!/bin/bash
SCAN_PID=`pstree -sg $1 |  head -n 1 | grep -Po 'shim\([0-9]+\)---[a-z]+\(\K[^)]*'`
docker ps -q | xargs docker inspect --format '{{.State.Pid}}, {{.Name}}' | grep "^${SCAN_PID},"

First line finds the container entry script and feeds it to the docker inspect.

Upvotes: 2

Clauz
Clauz

Reputation: 127

You can cycle through the parent processes of the target process using ps -o ppid= and at each step check if the PID of the parent matches one of the containers.

#!/bin/bash

targetpid=$1
parentpid=0

while [ $parentpid != 1 ]; do
    parentpid=$(ps -o ppid= $targetpid)
    docker ps -q | xargs docker inspect --format '{{.State.Pid}}, {{.Name}}' | grep "^$parentpid"
    targetpid="$parentpid"
done

Upvotes: 0

Alexcei Shmakov
Alexcei Shmakov

Reputation: 2343

Thank you @Alex Past and @Stanislav for the help. But I did not get full answers for me. I combined them.
In summary I has got next.

First

pstree -sg <PID>

where PID is the process's PID from the command top

In output I am getting parent PID for the systemd parent process. This PID is docker container's PID.

After I execute 

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

where %PID% is this parent PID.

In result I have docker's CONTAINER ID.

That's what I wanted

Upvotes: 52

Cyclonecode
Cyclonecode

Reputation: 29991

You should be able to use exec against each running container checking if the pid exists. Of course the same process id could exists in more than one container. Here is a small bash script that search for a running process based on the supplied pid in each container:

#!/bin/bash

for container in $(docker ps -q); do
  status=`docker exec $container ls /proc/$1 2>/dev/null`
  if [ ! -z "$status" ]; then
    name=`docker ps --filter ID=$container --format "{{.Names}}"`
    echo "PID: $1 found in $container ($name)"
    break;
  fi
done;

For example:

./find-process.sh 1

Upvotes: 2

Alexander Paschenko
Alexander Paschenko

Reputation: 721

You can find all parents for this process:

pstree -sg <PID>

This chain will be contains the container

Upvotes: 4

Stanislav
Stanislav

Reputation: 28096

I suppose you need something like this:

 docker ps -q | xargs docker inspect --format '{{.State.Pid}}, {{.Name}}' | grep "%PID%"

Upvotes: 9

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