mehr74 / gitlab-runner

Private GitLab Runner

Table of Contents

• Introduction
• Create a demo project
• Install Gitlab runner
• Register GitLab runner for the demo project
• Run CI/CD on the demo project
• Conclusion

Introduction

GitLab has a limit on the number of minutes we can use CI/CD runners. This is a problem for us because we have projects that consume a lot of minutes and we want to run CI/CD on all of them. There are three solutions to this problem:

1. Buy more minutes
2. Create a private runner
3. Limit the number of minutes used by a project

This document describes how we can benefit from private runners. For this purpose, we create a demo project on GitLab and setup a private runner on a virtual machine. We then use the private runner to run CI/CD on the demo project.

Create a demo project

For the demo project, we create an empty repository on GitLab, with the following example CI/CD configuration file:

build-job:
  stage: build
  script:
    - echo "We are building the app"
    - sleep 10
    - echo "Build is complete"

test-job:
  stage: test
  script:
    - echo "We are testing the app"
    - sleep 20
    - echo "Testing is complete"

deploy-job:
  stage: deploy
  script:
    - echo "We are deploying the app"
    - sleep 30
    - echo "Deployment is complete"

The configuration file defines three jobs, each of which sleeps for a certain amount of time. The purpose of this is to simulate a real-world scenario where the jobs take a long time to complete.

After creating the project with the above configuration file, we can see that the CI/CD pipeline has been triggered and is running.

The pipelines consumes about three minutes of CI/CD minutes.

Install GitLab Runner

We follow the steps in the GitLab documentation to setup a private runner on a Linux virtual machine.

First, we install the GitLab Runner package:

curl -LJO "https://gitlab-runner-downloads.s3.amazonaws.com/latest/deb/gitlab-runner_amd64.deb"
dpkg -i gitlab-runner_amd64.deb

After installing the package, we should be able to run the following command:

$ gitlab-runner -h
NAME:
   gitlab-runner - a GitLab Runner

USAGE:
   gitlab-runner [global options] command [command options] [arguments...]

VERSION:
   16.8.0 (c72a09b6)

AUTHOR:
   GitLab Inc. <[email protected]>
...

The output of the command shows that the GitLab Runner has been installed successfully. The version of the GitLab Runner should be the same as the version of the GitLab server.

Register GitLab runner for the demo project

We get back to our demo project. From the menu on the left, we select Settings -> CI/CD -> Runners.

From the Project Runners section, we click on the New project runner button. We choose Linux as the Operating System and add demo as Tags.

This will show us the registration token, as well as the command to register the runner. We copy the command and run it on the virtual machine where we installed the GitLab Runner.

We use Docker as the executor for the runner, and choose the ubuntu:latest image.

The GitLab Runner is now registered for the demo project. It now accepts jobs with tag demo. To enable the runner to run jobs without tags, we go to the Settings -> CI/CD -> Runners page, and click on the Edit button of our new GitLab Runner. We then check the Indicates whether this runner can pick jobs without tags checkbox.

Run CI/CD on the demo project

In the end, we can re-run our pipeline on the demo project. This time, the pipeline will be run by our private runner.

Conclusion

GitLab private runners are useful when we want to run CI/CD on projects that consume a lot of minutes. We can create a private runner on a virtual machine and register it for the projects that we want to run CI/CD on. The private runner will then run the CI/CD jobs for these projects.