docker in docker

how to run docker in docker container?

  • Dockerfile

    FROM ubuntu:20.04
USER root
RUN apt update
RUN apt install docker.io -y

  • build and run

    docker build -t docker-in-docker .
docker run -it --rm docker-in-docker bash

  • call docker in container

    root@6d0d4893b1ab:/# docker run hello-world
docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.

how to fix it?

  1. run dockerd in contaier
    but I failed, I don’t know why

  2. mount docker.sock in container

    docker run -it --rm -v /var/run/docker.sock:/var/run/docker.sock docker-in-docker bash

    this solution is work.