Docker Automation (Jenkins Server)

Project goal

Using Ansible on a managed Ubuntu node:

Install Docker
Start the Docker service
Run the Jenkins LTS container
Open the Jenkins UI in a browser

Control Node → Ansible playbook → Managed Node → Docker → Jenkins container

Prerequisites

Requirement	Notes
Ubuntu managed node	SSH from control node works (`ansible all -m ping`)
Security group	`22` (SSH), `8080` (Jenkins UI)

Playbook

mkdir -p playbooks
vim playbooks/jenkins.yml

---
- name: Install Docker and run Jenkins
  hosts: all
  become: true
 
  tasks:
    - name: Install Docker
      apt:
        name: docker.io
        state: present
        update_cache: true
 
    - name: Start Docker service
      service:
        name: docker
        state: started
        enabled: true
 
    - name: Add ubuntu user to docker group
      user:
        name: ubuntu
        groups: docker
        append: true
 
    - name: Reset SSH connection
      meta: reset_connection
 
    - name: Remove existing Jenkins container
      shell: docker rm -f jenkins
      ignore_errors: true
      changed_when: false
 
    - name: Run Jenkins container
      shell: |
        docker run -d \
          --name jenkins \
          --restart unless-stopped \
          -p 8080:8080 \
          -p 50000:50000 \
          -v jenkins_home:/var/jenkins_home \
          -v /var/run/docker.sock:/var/run/docker.sock \
          -v /usr/bin/docker:/usr/bin/docker \
          --user root \
          jenkins/jenkins:lts
      args:
        creates: /var/lib/docker/containers # soft guard; prefer community.docker in prod
 
    - name: Verify Jenkins container
      shell: docker ps
      register: docker_output
      changed_when: false
 
    - name: Display running containers
      debug:
        var: docker_output.stdout_lines

ansible-playbook playbooks/jenkins.yml
ansible all -m shell -a "docker ps"

Access Jenkins

Open http://<managed-node-public-ip>:8080
Unlock Jenkins with the initial admin password:

ansible all -m shell -a \
  "docker exec jenkins cat /var/jenkins_home/secrets/initialAdminPassword"

Install suggested plugins and create an admin user

Useful checks

ansible all -m shell -a "docker logs jenkins --tail 50"
ansible all -m shell -a "docker exec jenkins java -version"

Command	Purpose
`docker ps`	Running containers
`docker logs jenkins`	Troubleshooting
`docker rm -f jenkins`	Remove container

Mounting the Docker socket gives Jenkins powerful host access — fine for labs, lock down for production. Prefer community.docker.docker_container over raw shell when you harden this playbook.

Mini assignment: add OpenJDK 17 install and a health-check task that fails the play if port 8080 is not listening.

Requirement

Notes

Ubuntu managed node

SSH from control node works (ansible all -m ping)

Security group

22 (SSH), 8080 (Jenkins UI)

Playbook

mkdir -p playbooks
vim playbooks/jenkins.yml

---
- name: Install Docker and run Jenkins
  hosts: all
  become: true
 
  tasks:
    - name: Install Docker
      apt:
        name: docker.io
        state: present
        update_cache: true
 
    - name: Start Docker service
      service:
        name: docker
        state: started
        enabled: true
 
    - name: Add ubuntu user to docker group
      user:
        name: ubuntu
        groups: docker
        append: true
 
    - name: Reset SSH connection
      meta: reset_connection
 
    - name: Remove existing Jenkins container
      shell: docker rm -f jenkins
      ignore_errors: true
      changed_when: false
 
    - name: Run Jenkins container
      shell: |
        docker run -d \
          --name jenkins \
          --restart unless-stopped \
          -p 8080:8080 \
          -p 50000:50000 \
          -v jenkins_home:/var/jenkins_home \
          -v /var/run/docker.sock:/var/run/docker.sock \
          -v /usr/bin/docker:/usr/bin/docker \
          --user root \
          jenkins/jenkins:lts
      args:
        creates: /var/lib/docker/containers # soft guard; prefer community.docker in prod
 
    - name: Verify Jenkins container
      shell: docker ps
      register: docker_output
      changed_when: false
 
    - name: Display running containers
      debug:
        var: docker_output.stdout_lines

ansible-playbook playbooks/jenkins.yml
ansible all -m shell -a "docker ps"

Useful checks

ansible all -m shell -a "docker logs jenkins --tail 50"
ansible all -m shell -a "docker exec jenkins java -version"

Command

Purpose

docker ps

Running containers

docker logs jenkins

Troubleshooting

docker rm -f jenkins

Remove container

Mounting the Docker socket gives Jenkins powerful host access — fine for labs, lock down for production. Prefer community.docker.docker_container over raw shell when you harden this playbook.

Mini assignment: add OpenJDK 17 install and a health-check task that fails the play if port 8080 is not listening.