GitLab Kubernetes Agent

The following text describes how to install GitLab Kubernetes Agent step by step.

Following the steps should leave you with functional agent and knowledge of making manifest files.

Prerequisites

• Namespace on your cluster
• Gitlab repository
• kubectl

Define a configuration repository

In your desired repository, add the agent configuration file: .gitlab/agents/<agent-name>/config.yaml

Make sure that <agent-name> conforms to the Agent’s naming format.

gitops:
    manifest_projects:
        - id: <Your Project ID>
          default_namespace: <Your Namespace>
          paths:
              - glob: '/manifest/*.{yaml,yml,json}'

Note: <Your Project ID> can be replaced by your project path.

Connect to cluster

• Register agent and get agent token.

  In your project go to:

  Infrastructure -> Kubernetes clusters -> Install a new agent

  Select an agent -> Register

  An agent token will appear, copy it. Be careful, the token is not accessible twice.

• Make an opaque secret named gitlab-kubernetes-agent-token with key named token, value=<Your Agent Token>

  By kubectl: kubectl create secret generic -n <Your Namespace> gitlab-kubernetes-agent-token --from-literal=token=<Your Token>

• Download deployment file resources.yaml.

  In the file, in this section:

  apiVersion: rbac.authorization.k8s.io/v1
  kind: Role
  metadata:
    name: gitlab-kubernetes-agent-role
  rules:
  - resources: ["configmaps", "secrets", "pods"]
    apiGroups: 
    - ""
    verbs: ["get", "list", "watch", "create", "update", "delete", "patch"]
  - resources: ["deployments", "statefulsets"]
    apiGroups:
    - "apps"
    verbs: ["get", "list", "watch", "create", "update", "delete", "patch"]

  Specify the resources and verbs to your choosing. You can list all resources you have permission to by this command kubectl api-resources --verbs=list -n <Your Namespace>

• Apply the deployment with the following command: kubectl apply -n <Your Namespace> -f resources.yaml

• Check if the agent is running. Either in rancher or using kubectl kubectl get pods -n <Your Namespace>

Manage deployments

• In your repository make manifest file: /manifest/manifest.yaml

For the purpose of testing the agent, we will make simple manifest file that will create ConfigMap in <Your Namespace>.

apiVersion: v1
kind: ConfigMap
metadata:
  name: test-map
  namespace: <Your Namespace>  # Can be any namespace managed by you that the agent has access to.
data:
  key: value

If everything went smoothly, you should have a ConfigMap named test-map.