Jenkins- Day -1

 step-by-step guide for setting up Jenkins on an EC2 instance running Amazon Linux 2 and performing various tasks:

### Step 1: Set Up Jenkins on an EC2 Instance (Amazon Linux 2)

1. Launch an EC2 Instance:

   - Go to the AWS Management Console.

   - Launch a new EC2 instance.

   - Choose an Amazon Machine Image (AMI) for Amazon Linux 2.

   - Select an instance type (e.g., t2.micro for free tier).

   - Configure instance details, add storage, and add tags as needed.

   - Configure security group: Add rules to allow HTTP (port 80) and custom TCP rule for Jenkins (port 8080).

   - Review and launch the instance.

2. Connect to the EC2 Instance:

   - Connect to your instance via SSH using the key pair you created.

3. Install Jenkins:

   - Update the package index:

     ```bash

     sudo yum update -y

     ```

   - Install Java (Jenkins requires Java):

     ```bash

     sudo amazon-linux-extras install java-openjdk11 -y

     ```

   - Add Jenkins repository and key:

     ```bash

     sudo wget -O /etc/yum.repos.d/jenkins.repo \

         https://pkg.jenkins.io/redhat-stable/jenkins.repo

     sudo rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io.key

     ```

   - Install Jenkins:

     ```bash

     sudo yum install jenkins -y

     ```

   - Start Jenkins:

     ```bash

     sudo systemctl start jenkins

     ```

   - Enable Jenkins to start on boot:

     ```bash

     sudo systemctl enable jenkins

     ```

### Step 2: Check the Jenkins Port

1. Verify Jenkins is Running:

   ```bash

   sudo systemctl status jenkins

   ```

2. Check Jenkins Port:

   - By default, Jenkins runs on port 8080. Verify by opening a browser and navigating to:

     ```

     http://<your-ec2-public-ip>:8080

     ```

### Step 3: Add the Port to Security Group

1. Update Security Group:

   - Go to the AWS Management Console.

   - Navigate to EC2 Dashboard > Instances.

   - Select your instance and note the security group.

   - Navigate to Security Groups under Network & Security.

   - Select your security group and edit inbound rules.

   - Add a custom TCP rule for port 8080.

### Step 4: Check the Home Directory

1. Locate Jenkins Home Directory:

   ```bash

   echo $JENKINS_HOME

   ```

   - Default location: `/var/lib/jenkins`

### Step 5: Post-Install Task

1. Unlock Jenkins:

   - Get the initial admin password:

     ```bash

     sudo cat /var/lib/jenkins/secrets/initialAdminPassword

     ```

   - Use this password to unlock Jenkins via the web interface.

2. Install Suggested Plugins:

   - Follow the setup wizard to install suggested plugins.

3. Create Admin User:

   - Set up your admin user as prompted by the setup wizard.

### Step 6: Create a Freestyle Job

1. Create a New Freestyle Project:

   - In Jenkins dashboard, click on "New Item".

   - Enter an item name (e.g., "SampleProject").

   - Select "Freestyle project" and click OK.

2. Configure the Job:

   - In the project configuration page, add a simple build step:

     - Under "Build", click "Add build step" and select "Execute shell".

     - Enter a shell command, e.g., `echo "Hello, Jenkins!"`.

   - Save the configuration.

### Step 7: Find the Workspace Location

1. Locate Workspace:

   - The workspace for the job can be found at:

     ```bash

     /var/lib/jenkins/workspace/<your-job-name>

     ```

### Step 8: Check the Console Output

1. Run the Job and Check Output:

   - Go to your project's page.

   - Click "Build Now" to run the job.

   - Click on the build number (e.g., #1) in the "Build History" on the left.

   - Click "Console Output" to view the job's output.

By following these steps, you'll have a Jenkins instance set up on an EC2 instance running Amazon Linux 2, with the ability to create and manage jobs, and access various Jenkins features.