Testing/CI/KubernetesRunners

To be able to run Gitlab CI jobs on a Kubernetes cluster, a Gitlab Runner must be installed [1].

Deployment

This sections documents the steps taken to deploy a GitLab Runner instance on a Azure Kubernetes cluster by using Helm [2].

Kubernetes Cluster

Create a Kubernetes cluster on Azure (AKS). Single node pool "agentpool" for the Kubernetes system pods. Enable virtual nodes [3] to have on-demand capacity for the CI workloads.

CLI

Follow the docs to Install the Azure CLI.

Alternatively, run the Azure CLI in a container [4]:

podman run -it mcr.microsoft.com/azure-cli

Install the Kubernetes CLI (kubectl) [5]:

az aks install-cli

Install the Helm CLI [6]:

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Sign in

Sign in to Azure [7]:

az login

Connect to your Kubernetes Cluster. Open the Azure web dashboard for your cluster and push the "Connect" button. A list of commands will be displayed to connect to your cluster. Something like the following:

az account set --subscription ...
az aks get-credentials ...

Register the containers provider, needed for virtual nodes:

az provider register --namespace Microsoft.ContainerInstance

Gitlab

Register the new runner [8].

Gitlab Runner

Now it's time to install the Gitlab runner with Helm [9].

Create a namespace:

kubectl create namespace "gitlab-runner"

Create a values.yaml file for your runner configuration [10] like the snippet below.

Enabling RBAC support [11] seems to be needed [12] with the default AKS configuration.

nodeSelector and tolerations are needed for the pods to run on the virtual nodes [13] [14].

gitlabUrl: "https://gitlab.com/"
runnerRegistrationToken: ""
rbac:
  create: true
runners:
  config: |
    [[runners]]
      [runners.kubernetes]
        [runners.kubernetes.node_selector]
          "kubernetes.io/role" = "agent"
          "beta.kubernetes.io/os" = "linux"
          "type" = "virtual-kubelet"
        [runners.kubernetes.node_tolerations]
          "virtual-kubelet.io/provider=azure" = "NoSchedule"

Deploy the runner:

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

If you change the configuration in values.yaml, apply it with the upgrade command [15]:

helm upgrade --namespace gitlab-runner gitlab-runner -f values.yaml gitlab/gitlab-runner

Pause your runner before upgrading it to avoid service disruptions.