Jenkins Agent with Docker in Docker

A full fledged Docker in Docker image to act as a Jenkins Agent. Based on buildpack-deps:focal, it is a mashup of jenkins/inbound-agent with docker:dind.

• Source code: https://github.com/felipecrs/jenkins-agent-dind
• Docker image: https://hub.docker.com/r/felipecrs/jenkins-agent-dind

Features

• Based on Ubuntu 20.04 Focal Fossa: a more common OS to run your builds.
• From buildpack-deps: a image with many common dependencies installed, run your builds without hassle.
• It contains the latest release of agent.jar: even more up-to-date then jenkins/agent itself.
• Fully working Docker in Docker: run your docker build commands with no intervention and share of resources between the host.
• Act just as a Jenkins Agent out-of-the-box: run ephemeral build containers by using Docker Plugin (or Kubernetes Plugin) for Jenkins. Works as the official jnlp/inbound-agent.

Usage

Command line

Spin this agent in shell, if you want to play with it:

# Fetches the latest version
docker pull ghcr.io/felipecrs/jenkins-agent-dind
# -ti: allocates a pseudo-TTY in order to run bash
# --rm: removes the container after using it (don't forget to remove the volumes created by it)
# --privileged: needed for running Docker in Docker
docker run -ti --rm --privileged felipecrs/jenkins-agent-dind bash

Agent Template in Docker Cloud configuration on Jenkins

Kubernetes Plugin Pod Template

The following is the Pod definition that you can use as a Pod template with the Kubernetes Plugin. It contains optimizations to allow running KinD within the pod as well.

apiVersion: v1
kind: Pod
spec:
  containers:
  - name: jnlp
    image: ghcr.io/felipecrs/jenkins-agent-dind:latest
    imagePullPolicy: Always
    securityContext:
      privileged: true
    workingDir: /home/jenkins/agent
    volumeMounts:
      - mountPath: /home/jenkins/agent
        name: workspace-volume
      - mountPath: /lib/modules
        name: lib-modules
        readOnly: true
      - mountPath: /sys/fs/cgroup
        name: sys-fs-cgroup
  hostNetwork: false
  automountServiceAccountToken: false
  enableServiceLinks: false
  dnsPolicy: Default
  restartPolicy: Never
  terminationGracePeriodSeconds: 60
  volumes:
    - name: workspace-volume
      emptyDir: {}
    - name: lib-modules
      hostPath:
        path: /lib/modules
        type: Directory
    - name: sys-fs-cgroup
      hostPath:
        path: /sys/fs/cgroup
        type: Directory