我们可以在一个在Ubuntu 18.04的虚拟盒中运行的docker容器中运行docker吗？

Question

I want to run docker inside another docker container. My main container is running in a virtualbox of OS Ubuntu 18.04 which is there on my Windows 10. On trying to run it, it is showing me as:

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

How can I resolve this issue?

Answer 1

Yes, you can do this. Check for dind (docker in docker) on docker webpage how to achieve it: https://hub.docker.com/_/docker

Your error indicates that either dockerd in the top level container is not running or you didn't mount docker.sock on the dependent container to communicate with dockerd running on your top-level container.

Answer 2

I am running electric-flow in a docker container in my Ubuntu virtual-box using this docker command: docker run --name efserver --hostname=efserver -d -p 8080:8080 -p 9990:9990 -p 7800:7800 -p 7070:80 -p 443:443 -p 8443:8443 -p 8200:8200 -i -t ecdocker/eflow-ce. Inside this docker container, I want to install and run docker so that my CI/CD pipeline in electric-flow can access and use docker commands.

From your above description, ecdocker/eflow-ce is your CI/CD solution container, and you just want to use docker command in this container, then you did not need dind solution. You can just access to a container's host docker server.

Something like follows:

docker run --privileged --name efserver --hostname=efserver -d -p 8080:8080 -p 9990:9990 -p 7800:7800 -p 7070:80 -p 443:443 -p 8443:8443 -p 8200:8200 -v $(which docker):/usr/bin/docker -v /var/run/docker.sock:/var/run/docker.sock -i -t ecdocker/eflow-ce

Compared to your old command:

• Add --privileged
• Add -v $(which docker):/usr/bin/docker , then you can use docker client in container.
• Add -v /var/run/docker.sock:/var/run/docker.sock , then you can access host's docker daemon using client in container.