Running Docker in Jenkins (in Docker)

jenkins.md

1. Create a Dockerfile

FROM jenkins/jenkins:lts
 
USER root
RUN apt-get update \
      && apt-get install -y sudo \
      && rm -rf /var/lib/apt/lists/*
RUN echo "jenkins ALL=NOPASSWD: ALL" >> /etc/sudoers
 
USER jenkins

We need to give the jenkins user sudo privileges in order to be able to run Docker commands inside the container.

2. Build your jenkins container

$ docker build -t my_jenkins .

3. Run your container

$ docker run -d -v /var/run/docker.sock:/var/run/docker.sock -v $(which docker):/usr/bin/docker -p 8080:8080 -p 50000:50000 my_jenkins

4. Once your container is running, navigate to http://localhost:8080, install the default plugins and setup your Jenkins admin.
5. Go to Manage Jenkins -> Manage Plugins. Under the Available tab search for docker and install Docker and Docker Pipeline plugins.
6. Create a pipeline (Freestyle or Multibranch pipeline) and test!
7. If you get Docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock, try these:
8. Add jenkins user to the docker group and restart the Jenkins:

$ sudo usermod -a -G docker jenkins
$ sudo service jenkins restart

You can check it was successful by doing grep docker /etc/group and see something like this:

docker:x:998:jenkins

Then change your users group ID to docker:

newgrp docker

Finally, log out and log in again.

Use DIND instead

• https://www.tiuweehan.com/blog/2020-09-10-docker-in-jenkins-in-docker/
• https://www.jenkins.io/doc/book/installing/docker/