Friday, October 28, 2022

[SOLVED] How to execute a Bash command only if a Docker container with a given name does not exist?

Issue

On a Jenkins machine I would like to create a docker container with a specified name only if it does not already exist (in a shell script). I thought I might run the command to create the container regardless and ignore the failure if there was one, but this causes my jenkins job to fail.

Hence, I would like to know how I can check if a docker container exists or not using bash.


Solution

You can check for non-existence of a running container by grepping for a <name> and fire it up later on like this:

[ ! "$(docker ps -a | grep <name>)" ] && docker run -d --name <name> <image>

Better:

Make use of https://docs.docker.com/engine/reference/commandline/ps/ and check if an exited container blocks, so you can remove it first prior to run the container:

if [ ! "$(docker ps -q -f name=<name>)" ]; then
    if [ "$(docker ps -aq -f status=exited -f name=<name>)" ]; then
        # cleanup
        docker rm <name>
    fi
    # run your container
    docker run -d --name <name> my-docker-image
fi


Answered By - ferdy
Answer Checked By - Dawn Plyler (WPSolving Volunteer)
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