Install Jenkins using Ansible Playbook

 

What is Jenkins & Ansible?

Jenkins is one of the most powerful and commonly used Continuous Integration and Deployment (CI/CD) tool in the DevOps world. A Job in Jenkins denotes an automated flow created to do a particular set of tasks. There are different types of Jobs available in the Jenkins like Freestyle, Pipeline, DSL, etc. with the most common being the Jenkins Pipeline job.

Ansible is one of the most powerful and commonly used open-source Configuration management tool in the DevOps world. It is widely used for software provisioning, automate apps, configuration management and application deployment. It is compatible to run on almost all platforms.

Today's Agenda

In this post, we will learn how to install Jenkins using Ansible Playbook. We will do this installation using the Normal Jenkins Installation with default user token generated and default plugins installed. Refer to this link install Jenkins using the Customised Installation (i.e. with Custom User Credentials and Plugins).

Prerequisite

This post has been prepared for the audience who : 

1. Have access to a system with Ansible installed and configured on it.
2. Have a very basic understanding of Linux commands to debug if there is any errors.
3. Have a server setup on which Jenkins needs to be installed.
4. And finally, are eager to learn and try such powerful tools.

Let's get started

 The Normal Way (With Default User & Plugins) 

Step 1: Create an empty Ansible playbook structure for Jenkins.

Create the main work directory in which you will run the below steps.

$ mkdir -p ansible/roles/ $ cd ansible/ $ touch Jenkins.yml ansible.cfg

Run the below command to create a default directory structure that we can change further.

 

$ cd roles/ $ ansible-galaxy init jenkins

Output of the above command

Now, we will make changes in the following 2 files:

 

    1.  ansible > roles > jenkins > defaults > main.yml

    2.  ansible > roles > jenkins > tasks > main.yml

Step 2: Change required playbook files for Jenkins.

In the Ansible playbook file structure, tasks > main.yml file include the main installation steps.

--- #  tasks file for Jenkins - name: Install packages and dependencies apt: name={{ item }} update_cache=yes state=present with_items:       - openjdk-8-jdk  # this specific version is needed for Jenkins to run       - libfontconfig       - libffi-dev       - libncurses5-dev - name: Add the Jenkins public GPG key to the apt repo apt_key: url=http://pkg.jenkins-ci.org/debian/jenkins-ci.org.key                       state=present - name: Add Jenkins apt repo to the trusted sources list apt_repository: repo='deb http://pkg.jenkins-ci.org/debian binary/'                                    update_cache=yes                                    state=present - name: Install Jenkins server apt: name=jenkins state=present - name: install python3-pip apt:      pkg:           - python3-pip - name: Install additional Python packages pip: name={{ item }} state=latest with_items:       - ansible       - boto       - flake8       - passlib - name: Start jenkins server   systemd:       name: jenkins       enabled: yes       state: started - name: download jenkins cli jar file get_url:       url: "http://localhost:8080/jnlpJars/jenkins-cli.jar"       dest: "{{ jenkins_home }}/jenkins-cli.jar"       mode: '0664' - name: Restart jenkins server systemd:       name: jenkins       state: restarted

In the Ansible playbook file structure, defaults > main.yml file include the variables that we want to use in our main installation script (tasks > main.yml) file.

 

--- # defaults file for Jenkins jenkins_home: /var/lib/jenkins jenkins_hostname: localhost jenkins_http_port: 8080

Step 3: Provision file to add Jenkins server details.

Now we make changes in the files that will help Ansible to know the server details on which Jenkins needs to be installed.

 

    1.  ansible > jenkins.yml

    2.  sensible > ansible.cfg

In Ansible, jenkins.yml file includes the hosts, users, basic variables, roles, etc that playbook will need while running.

--- - name: Provision Jenkins CI on server    hosts: jenkins    remote_user: ubuntu    become: yes    roles:        - jenkins    vars:        - update_apt_cache: yes

In Ansible playbook file structure, ansible.cfg file includes the host's authentication details like IP, pem path, etc.

 

Replace the <jenkins_private_ip> and <pem_path> with the actual values.

 

[jenkins] <jenkins_private_ip>   ansible_ssh_private_key_file=<pem_path>

Step 4: Run the playbook to get the results.

Run the below command and wait for it to execute successfully.

 

$ ansible-playbook -i ansible.cfg jenkins.yml