installing jenkins with terraform and ansible in DigitalOcean droplet

Jenkins is an open-source project written in Java that runs on Windows, macOS, and other Unix-like operating systems. The first point of attraction in Jenkins is that it is open source. Apart from that, it is community-supported and primarily deployed on-premises, but it can also run-on cloud servers. Its integrations with Docker and Kubernetes take advantage of containers to roll out even more frequent releases.

In our project, we will use terraform to create our server on digital ocean and we will do the configuration and installation with Ansible.

Prerequisites

1. Terraform already install 
2. Ansible already install
3. A digital ocean account

Deploying the virtual machine

We will use a 4 Gib virtual machine host on digital ocean, since we are going to use terraform to connect to our account, we will need to create a token in digitalOcean by following the steps in this link https://docs.digitalocean.com/reference/api/create-personal-access-token/ .

Once you get your token, you can generate an RSA key with ssh-keygen. You just have to run the command :

ssh-keygen -t rsa

For security reasons, we are going to use a variable to store this token, we do not want any random person to get access to our environment, so it is good practice to store it in an environment variable.

We will call it DO_PAT, to do so, we run the command 

export DO_PAT="your_personal_access_token"

  

To use the DigitalOcean provider with Terraform, you have to tell Terraform about it and configure the plugin with the proper credential variables. Create a file called provider.tf, which will store the configuration for the provider:

terraform {

  required_providers {

    digitalocean = {

      source = "digitalocean/digitalocean"

      version = "~> 2.0"

    }

  }

}

variable "do_token" {}

variable "pvt_key" {}

provider "digitalocean" {

  token = var.do_token

}

data "digitalocean_ssh_key" "terraform" {

  name = "terraform"

}

you can create your file server.tf, this file will have the config for your server in digital ocean.

resource "digitalocean_droplet" "server-1" {

    image = "ubuntu-22-10-x64"

    name = "jenkins"

    region = "tor1"

    size = "s-2vcpu-4gb"

    ssh_keys = [

      data.digitalocean_ssh_key.terraform.id

    ]

}

Setting the TF_LOG environment variable to 1 will enable detailed logging of what Terraform is trying to do. You can set it by running:

 

export TF_LOG=DEBUG

Initialize Terraform for your project by running:

terraform init

 Run the terraform plan command to see the execution plan, or what Terraform will attempt to do to build the infrastructure you described. You will have to specify the values for your DigitalOcean Access Token and the path to your private key, as your configuration uses this information to access your Droplet to install Nginx. Run the following command to create a plan:

terraform plan \

  -var "do_token=${DO_PAT}" \

  -var "pvt_key=$HOME/.ssh/id_rsa"

run terraform apply command to execute the current plan:

terraform apply \

  -var "do_token=${DO_PAT}" \

  -var "pvt_key=$HOME/.ssh/id_rsa"

At the end of all this, you will have a droplet name Jenkins up and running in digitalOcean

Configure the Jenkins server.

below you have the playbook that will allow you to install your Jenkins server on ubuntu. Do not forget to create your inventory file, it is just a file with your server address. It tells ansible where are your servers 

Just run the command:  

ansible-playbook -i inventory playbook.yml

You should have a fully functional Jenkins server running on http://YOUR_SERVER_IP_ADDRESS:8080

Playbook.yml

---

- hosts: jenkins

  become: true

  become_user: root

  tasks:

    - name: Update apt repo and cache on all Debian/Ubuntu boxes

      apt: update_cache=yes force_apt_get=yes cache_valid_time=3600

    - name: Upgrade all packages on servers

      apt: upgrade=dist force_apt_get=yes

    - name: Check if a reboot is needed on all servers

      register: reboot_required_file

      stat: path=/var/run/reboot-required get_md5=no

    - name: Reboot the box if kernel updated

      reboot:

        msg: "Reboot initiated by Ansible for kernel updates"

        connect_timeout: 5

        reboot_timeout: 300

        pre_reboot_delay: 0

        post_reboot_delay: 30

        test_command: uptime

      when: reboot_required_file.stat.exists

    - name: Installing Java using Ansible

      become: yes

      apt:

        name: "{{ packages }}"

        state: present

      vars:

        packages:

           - openjdk-11-jdk

    - name: add the repository key to the system

      ansible.builtin.shell: curl -fsSL https://pkg.jenkins.io/debian-stable/jenkins.io.key | sudo tee /usr/share/keyrings/jenkins-keyring.asc > /dev/null

      args:

        executable: /bin/bash

    - name: add the repository key to the system

      ansible.builtin.shell: echo deb [signed-by=/usr/share/keyrings/jenkins-keyring.asc]  https://pkg.jenkins.io/debian-stable binary/ | sudo tee /etc/apt/sources.list.d/jenkins.list > /dev/null

      args:

        executable: /bin/bash

    - name: add the repository key to the system

      ansible.builtin.shell: apt update -y

      args:

        executable: /bin/bash

    - name: install jenkins

      apt:

        name: jenkins

        state: latest

    - name: start jenkins

      service:

          name: jenkins

          enabled: true

          state: started

inventory

[jenkins]

YOUR_SERVER_IP_ADDRESS