How to run Jenkins in development environment (on macOS) (STARTER)

This is a step by step guide on how to set up Jenkins on your local machine and connect to it from your GitLab instance. GitLab triggers webhooks on Jenkins, and Jenkins connects to GitLab using the API. By running both applications on the same machine, we can make sure they are able to access each other.

Install Jenkins

Install Jenkins and start the service using Homebrew.

brew install jenkins
brew services start jenkins

Configure GitLab

GitLab does not allow requests to localhost or the local network by default. When running Jenkins on your local machine, you need to enable local access.

1. Log into your GitLab instance as an administrator.

2. Go to Admin Area > Settings > Network.

3. Expand Outbound requests and check the following checkboxes:

   • Allow requests to the local network from web hooks and services
   • Allow requests to the local network from system hooks

For more details about GitLab webhooks, see Webhooks and insecure internal web services.

Jenkins uses the GitLab API and needs an access token.

1. Sign in to your GitLab instance.
2. Click on your profile picture, then click Settings.
3. Click Access Tokens.
4. Create a new Access Token with the API scope enabled. Note the value of the token.

Configure Jenkins

Configure your GitLab API connection in Jenkins.

1. Make sure the GitLab plugin is installed on Jenkins. You can manage plugins in Manage Jenkins > Manage Plugins.
2. Set up the GitLab connection:
   1. Go to Manage Jenkins > Configure System.
   2. Find the GitLab section and check the Enable authentication for '/project' end-point checkbox.
3. To add your credentials, click Add then choose Jenkins Credential Provider.
4. Choose GitLab API token as the type of token.
5. Paste your GitLab access token and click Add.
6. Choose your credentials from the dropdown menu.
7. Add your GitLab host URL. Normally http://localhost:3000/.
8. Click Save Settings.

For more details, see GitLab documentation about Jenkins CI.

Configure Jenkins Project

Set up the Jenkins project to run your build on. A Freestyle project is the easiest option because the Jenkins plugin updates the build status on GitLab. In a Pipeline project, updating the status on GitLab needs to be configured in a script.

1. On your Jenkins instance, go to New Item.

2. Pick a name, choose Freestyle or Pipeline and click ok.

3. Choose your GitLab connection from the dropdown.

4. Check the Build when a change is pushed to GitLab checkbox.

5. Check the following checkboxes:

   • Accepted Merge Request Events
   • Closed Merge Request Events

6. If you created a Freestyle project, choose Publish build status to GitLab in the Post-build Actions section.

   If you created a Pipeline project, updating the status on GitLab has to be done by the pipeline script. Add GitLab update steps as in this example:

   pipeline {
      agent any
   
      stages {
         stage('gitlab') {
            steps {
               echo 'Notify GitLab'
               updateGitlabCommitStatus name: 'build', state: 'pending'
               updateGitlabCommitStatus name: 'build', state: 'success'
            }
         }
      }
   }

Configure your GitLab project

To activate the Jenkins service:

1. Go to your project's page, then Settings > Integrations > Jenkins CI.
2. Check the Active checkbox and the triggers for Push and Merge request.
3. Fill in your Jenkins host, project name, username and password and click Test settings and save changes.

Test your setup

Make a change in your repository and open an MR. In your Jenkins project it should have triggered a new build and on your MR, there should be a widget saying Pipeline #NUMBER passed. It should also include a link to your Jenkins build.