Not able to run jenkins on AWS EC2 instance

I apologize for the inconvenience you're experiencing with running Jenkins on your AWS EC2 instance. Based on the information provided, there are a few potential reasons why you might be encountering this error:

1. Insufficient permissions: You may not have the necessary permissions to run Jenkins on the EC2 instance. Ensure that you have the correct IAM permissions associated with your instance, particularly the permissions to run and manage services.

2. Security group configuration: Check if your EC2 instance's security group allows inbound traffic on the port Jenkins is trying to use (typically port 8080). You may need to add a rule to allow this traffic.

3. Java version compatibility: Ensure that the Java version you've installed is compatible with the Jenkins version you're trying to run. Jenkins requires a specific version of Java to function correctly.

4. Instance resources: Verify that your EC2 instance has sufficient resources (CPU, memory) to run Jenkins. If the instance is too small, it may struggle to start the service.

5. Firewall settings: Check if there are any firewall settings on the EC2 instance itself that might be blocking Jenkins from starting or accessing necessary resources.

6. Jenkins configuration: There might be an issue with the Jenkins configuration files. Ensure they are correctly set up and have the necessary permissions.

To troubleshoot this issue:

1. Check the Jenkins log files for more detailed error messages. These are usually located in /var/log/jenkins/ or ~/.jenkins/logs/.

2. Verify that Jenkins is installed correctly and all dependencies are met.

3. Try running Jenkins with sudo privileges to rule out permission issues.

4. Ensure that the correct Java version is installed and set as the default.

5. Review your EC2 instance's security group and network settings to ensure they're not blocking Jenkins.

If you continue to face issues, you may want to provide more specific details about the error message you're seeing, which would help in diagnosing the problem more accurately.
Sources
Troubleshoot connection with EC2 Instance Connect | AWS re:Post
Troubleshoot Amazon EC2 instance launch issues - Amazon Elastic Compute Cloud
Connect to an Amazon EC2 instance using EC2 Instance Connect Endpoint - Amazon Elastic Compute Cloud

Hi,

You should follow this tutorial to get Jenkins up & running in your account: https://www.jenkins.io/doc/tutorials/tutorial-for-installing-jenkins-on-AWS/

You can also leverage the Bitnami's AMI where Jenkins is already installed and customized: https://bitnami.com/stack/jenkins/cloud/aws/amis

Best,

Didier