How to set up a highly available Jenkins master ?

This directory contains terraform configuration files required to set up a highly available Jenkins master in a single AWS region with multiple Availability Zones using:

• Elastic File System (EFS)
• Default VPC

What resources will be provisoned?

1. Elastic File System (EFS) - This is where JENKINS_HOME data will reside.
2. Auto Scaling Group - To automatically provision a new Jenkins master incase of a failure.
3. Launch Configuration - This will be used by the Auto Scaling Group to provision a new Jenkins master
4. Application Load Balancer (ALB) - pointing to your Auto Scaling group so that you can find Jenkins master using the load balancer DNS name.
5. Jenkins Master - This is the primary Jenkins master
6. Security Groups
   • EFS : Allow port 2049
   • Jenkins : Allow ports 8080, 22, 2049
   • ALB: Allow port 80

Prerequisites

AWS

1. AWS Account.
2. IAM Privileges to provision an EC2 instance.
3. AWS CLI credentials
4. SSH Keypair.

Terraform

1. Install Terraform v1.3.7 on your local machine.
2. AWS Credentials set as environment variables or as shared credentials under /$YOUR_HOME_DIRECTORY/.aws/credentials

Steps

• Be sure you are in the jenkins-ha directory.
• Create a file named terraform.tfvars.

• Add the following content to this file:

  • ssh_key_name = "<YOUR SSH KEY NAME"

  • region = "AWS REGION"

  • instance_type = "INSTANCE_TYPE"

  • NOTE

    • ssh_key_name is the name of the SSH Key you use to connect to your EC2 instance.

• Run the command terraform init to initialize your working directory.

• Run the command terraform apply and follow the prompts to provision your highly available Jenkins infrastructure.

• If everything runs successfully, terraform will output ALB DNS Name and EFS DNS Name. Enter the ALB DNS Name on a browser. You should see the unlock Jenkins screen. Follow the instructions to set up your Jenkins master.

• Note: Incase your primary Jenkins server goes down, a new one will automatically be provisioned.