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dockerdockerfilemountdocker-volume

What is the purpose of creating a volume between two docker.sock files in Docker?

I see this in many docker apps that are somehow related hardly on networking, but I can't understand this

Solution

  • Got it.

    https://jpetazzo.github.io/2015/09/03/do-not-use-docker-in-docker-for-ci/

    Let’s take a step back here. Do you really want Docker-in-Docker? Or do you just want to be able to run Docker (specifically: build, run, sometimes push containers and images) from your CI system, while this CI system itself is in a container?

    I’m going to bet that most people want the latter. All you want is a solution so that your CI system like Jenkins can start containers.

    And the simplest way is to just expose the Docker socket to your CI container, by bind-mounting it with the -v flag.

    Simply put, when you start your CI container (Jenkins or other), instead of hacking something together with Docker-in-Docker, start it with:

    docker run -v /var/run/docker.sock:/var/run/docker.sock

    Now this container will have access to the Docker socket, and will therefore be able to start containers. Except that instead of starting “child” containers, it will start “sibling” containers.