Installing gitlab-runner into a kubernetes cluster

24 Aug, 2022

Installing the gitlab runner is fairly simple.

Create a namespace

k8s$ kubectl create namespace gitlab-runner
k8s$ kubens gitlab-runner

Install the helm chart

Install the helm repo

k8s$ helm repo add gitlab https://charts.gitlab.io

Update the repo

k8s$ helm repo update gitlab

Check the current versions

k8s$ $ helm search repo -l gitlab/gitlab-runner
NAME                    CHART VERSION   APP VERSION     DESCRIPTION
gitlab/gitlab-runner    0.48.0          15.7.0          GitLab Runner
gitlab/gitlab-runner    0.47.1          15.6.1          GitLab Runner
gitlab/gitlab-runner    0.47.0          15.6.0          GitLab Runner
gitlab/gitlab-runner    0.46.1          15.5.1          GitLab Runner
gitlab/gitlab-runner    0.46.0          15.5.0          GitLab Runner
gitlab/gitlab-runner    0.45.2          15.4.2          GitLab Runner
...

Retrive your runner token from gitlab

Go to your group or project
Go to CICD
Go to Runners

You can access the token from there, it is a secret so treat it like one.

Configure your yaml file

Changes we made:

Input the token from above so it is associated with our account.
Configured the CPU and Memory limits to match our build requirements. Usually less is needed, but we have some heavy processing that happens in one of our image builds that needs more memory than usual.
Added tags to allow us to distinguish runners on different systems in our .gitlabci.yml files
Changed it to allow untagged jobs. This cluster is running on our on premise server so it doesn't cost extra to run like a cloud service would.
Privileged must be set to true for it to do Docker-In-Docker builds
Set the default image to ubuntu:16.04 This is getting old, but it still works. It should be upgraded soon.

gitlabUrl: https://gitlab.com./
runnerRegistrationToken: <RUNNER TOKEN>
rbac:
  create: false
concurrent: 30
runners:
  config: |
     [[runners]]
      name = "Color GC Runner"
      executor = "kubernetes"
      url = "https://gitlab.com/"
      [runners.kubernetes]
        helper_image_flavor = "ubuntu"
        service_account = "default"
        image = "ubuntu:16.04"
        namespace = "gitlab-runner"
        privileged = true
        image_pull_secrets = ["registry.gitlab.com/"]
        cpu_limit = "1"
        memory_limit = "1Gi"
        cpu_request = "1"
        memory_request = "1Gi"
        service_cpu_limit = "1"
        service_memory_limit = "1Gi"
        service_cpu_request = "1"
        service_memory_request = "1Gi"
        helper_cpu_limit = "1"
        helper_memory_limit = "1Gi"
        helper_cpu_request = "1"
        helper_memory_request = "1Gi"

  ## Specify if jobs without tags should be run.
  ## If not specified, Runner will default to true if no tags were specified. In other case it will
  ## default to false.
  ##
  ## ref: https://docs.gitlab.com/ce/ci/runners/#runner-is-allowed-to-run-untagged-jobs
  ##
  runUntagged: true

  tags: "private-k8s"

Install the chart

k8s$ helm install --namespace gitlab-runner gitlab-runner -f values.yaml gitlab/gitlab-runner

Install the Role Based Access Controls (RBAC)

This is needed to do in-cluster deployments. Basically, the runner can deploy to the cluster it is in as it is given cluster-admin permissions. This can be a security risk so only use it if necessary.

k8s$ kubectl create clusterrolebinding gitlab-runner-cluster-role --clusterrole=cluster-admin --serviceaccount=gitlab-runner:default

Verify it is running

k8s$ $ kubectl get pods
NAME                             READY   STATUS    RESTARTS   AGE
gitlab-runner-78557644cc-f58p7   1/1     Running   0          11m

Using it in a Gitlab CICD Pipeline

Add a pipeline job to the .gitlab-ci.yml

app-images:
  stage: build
  tags:
    - private-k8s
  script:
    - echo "here"
  when: manual

After this it can be run manually to verify it is working.