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How to Install GitLab on Kubernetes: A Complete Guide

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Installing GitLab on a Kubernetes cluster can seem like a daunting task, but with the right guidance, it can be a smooth and rewarding process. This guide will walk you through setting up your Kubernetes cluster, preparing for the GitLab installation, deploying GitLab using Helm, and performing essential post-installation steps. By the end of this guide, you’ll have a fully functional GitLab instance running on your Kubernetes cluster.

Key Takeaways

  • Setting up a Kubernetes cluster is the first step in installing GitLab.
  • Proper DNS configuration is crucial for your cluster’s functionality.
  • Helm simplifies the GitLab installation process on Kubernetes.
  • Post-installation steps are necessary to secure and access your GitLab instance.
  • GitLab Runners can be set up to handle CI/CD tasks within your Kubernetes cluster.

Setting Up Your Kubernetes Cluster

Choosing the Right Kubernetes Distribution

Selecting the right Kubernetes distribution is crucial. You have several options like GKE, EKS, and AKS. Each has its own benefits and drawbacks. GKE is great for Google Cloud users, while EKS and AKS are better for AWS and Azure users, respectively. Make sure to choose one that fits your needs and budget.

Configuring DNS for Your Cluster

DNS configuration is essential for your cluster’s accessibility. Set up a wildcard DNS that points to your cluster’s public IP. This will make it easier to manage and access your services. Use tools like CoreDNS for internal DNS management.

Installing Essential Tools

Before you start, install essential tools like kubectl and Helm. These tools will help you manage your cluster and deploy applications. Run the following commands to install them:

# Install kubectl
curl -LO "https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x ./kubectl
sudo mv ./kubectl /usr/local/bin/kubectl

# Install Helm
curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash

With these tools installed, you’re ready to move on to the next steps.

Preparing for GitLab Installation

Creating the GitLab Namespace

First, you need to create a namespace for GitLab. This helps in organizing and managing resources. Use the following command:

kubectl create namespace gitlab

This command sets up a dedicated space for all GitLab components.

Setting Up Persistent Storage

Persistent storage is crucial for GitLab to retain data even if pods are restarted. Create a PersistentVolumeClaim (PVC) using a YAML file. Here’s a sample configuration:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: gitlab-pvc
  namespace: gitlab
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

Apply this configuration with:

kubectl apply -f gitlab-pvc.yaml

Configuring Ingress and TLS

Ingress and TLS are essential for secure access to GitLab. First, set up an Ingress controller if you don’t have one. Then, create a TLS secret:

kubectl create secret tls gitlab-tls --key /path/to/tls.key --cert /path/to/tls.crt -n gitlab

Next, configure the Ingress resource to use this TLS secret. Here’s a sample Ingress configuration:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: gitlab-ingress
  namespace: gitlab
spec:
  tls:
  - hosts:
    - gitlab.example.com
    secretName: gitlab-tls
  rules:
  - host: gitlab.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: gitlab-webservice
            port:
              number: 80

Apply this configuration with:

kubectl apply -f gitlab-ingress.yaml

Note: Ensure your DNS is configured to point to your Ingress controller’s IP.

By following these steps, you ensure that your Kubernetes cluster is ready for a smooth GitLab installation.

Installing GitLab with Helm

Adding the GitLab Helm Repository

First, you need to add the GitLab repository to Helm. Run the following commands:

helm repo add gitlab https://charts.gitlab.io/
helm repo update

This will ensure you have access to the latest GitLab charts. Adding the GitLab repository is a crucial step before proceeding with the installation.

Customizing Your Helm Values

Before installing GitLab, you need to customize your Helm values. Create a values.yaml file and specify your configurations. Here are some common settings:

  • global.hosts.domain: Set this to your domain.
  • certmanager.install: Set to false if you don’t want to install Cert-Manager.
  • global.ingress.configureCertmanager: Set to false if you are using your own certificates.

Example:

global:
  hosts:
    domain: "your-domain.com"
  ingress:
    configureCertmanager: false
certmanager:
  install: false

Deploying GitLab Using Helm

Now, you can deploy GitLab using Helm. Run the following command:

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

This command will install GitLab in the gitlab namespace using the configurations specified in your values.yaml file. The --wait flag ensures that Helm waits for the deployment to complete before finishing.

Note: Make sure your Kubernetes cluster is properly configured before running the installation command. This includes setting up DNS and persistent storage.

After running the command, you should see an output similar to this:

NAME: gitlab
LAST DEPLOYED: Fri Dec 27 10:57:01 2019
NAMESPACE: gitlab
STATUS: deployed
REVISION: 1
NOTES:
WARNING: Automatic TLS certificate generation with cert-manager is disabled and no TLS certificates were provided. Self-signed certificates were generated.

You can now proceed to the post-installation steps to access and configure your GitLab instance.

Post-Installation Steps

Accessing the GitLab Web Interface

Once GitLab is up and running, you can access the web interface. Open your browser and navigate to the URL you configured during the installation. This is where you’ll manage your projects, users, and settings. Make sure everything is working as expected.

Retrieving Initial Root Password

To log in for the first time, you’ll need the initial root password. This password is stored in a Kubernetes secret. Run the following command to retrieve it:

kubectl get secret gitlab-initial-root-password -o jsonpath='{.data.password}' | base64 --decode

Use this password to log in as the root user and set up your account.

Disabling User Registration

For security reasons, you might want to disable user registration. This prevents unauthorized users from creating accounts. To do this, go to the Admin Area, navigate to Settings > General, and uncheck the Sign-up enabled option. Save your changes.

It’s crucial to secure your GitLab instance to prevent unauthorized access and potential security breaches.

Setting Up GitLab Runners

Creating a Namespace for Runners

First, create a dedicated namespace for your GitLab runners. This keeps things organized and makes management easier. Use the following command to create the namespace:

kubectl create namespace gitlab-runner

Having a separate namespace ensures that all resources related to the runners are isolated from other components in your cluster.

Registering a GitLab Runner

To register a GitLab runner, you need a registration token from GitLab. Navigate to your GitLab repository, go to Settings > CI/CD > Runners, and find the section titled "Set up a specific Runner manually." Copy the registration token provided.

Next, start a Docker container to perform the registration process. Run the following command:

docker run -it --entrypoint /bin/bash gitlab/gitlab-runner:latest

Inside the container, register the runner with this command:

gitlab-runner register

Follow the prompts and use the registration token you copied earlier. This will link your runner to your GitLab project.

Configuring the Runner for Kubernetes

Now, configure the runner to use the Kubernetes executor. This allows each job in your CI/CD pipeline to run as a pod in your Kubernetes cluster. Create a deployment file for the runner:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: gitlab-runner
  namespace: gitlab-runner
spec:
  replicas: 1
  selector:
    matchLabels:
      app: gitlab-runner
  template:
    metadata:
      labels:
        app: gitlab-runner
    spec:
      containers:
      - name: gitlab-runner
        image: gitlab/gitlab-runner:latest
        volumeMounts:
        - name: config
          mountPath: /etc/gitlab-runner/config.toml
          subPath: config.toml
      volumes:
      - name: config
        configMap:
          name: gitlab-runner-config

Apply the deployment with:

kubectl apply -f gitlab-runner-deployment.yaml

This deployment ensures that your runner is properly configured to handle CI/CD jobs in your Kubernetes cluster.

Tip: If you have a CI/CD pipeline, you have runners that are used to execute your jobs. These runners usually have a limited number of minutes available.

Check if the runner is connected by refreshing your repository’s settings page. A green dot next to the runner’s name indicates a successful connection.

Managing and Monitoring GitLab

Scaling GitLab Components

Scaling your GitLab components is crucial for maintaining performance as your user base grows. Start by identifying which components need scaling, such as the web service, Sidekiq, or the database. Use Kubernetes’ built-in scaling features to adjust the number of pods for each component. Regularly monitor resource usage to ensure your cluster remains healthy.

Monitoring GitLab Performance

GitLab offers a built-in solution for monitoring your Kubernetes cluster health. Use tools like Prometheus and Grafana to visualize metrics and set up alerts. Keep an eye on CPU, memory, and disk usage to catch any issues early. Consistent monitoring helps in maintaining optimal performance.

Backing Up GitLab Data

Regular backups are essential to prevent data loss. Use GitLab’s built-in backup tools to create scheduled backups of your repositories, databases, and configuration files. Store these backups in a secure, off-site location. Automate the backup process to ensure you always have a recent copy of your data.

Managing and monitoring your GitLab installation is key to ensuring a smooth and efficient workflow. Don’t overlook these steps to keep your system running smoothly.

Frequently Asked Questions

What is GitLab?

GitLab is a tool that combines code repository management, a container registry, and CI/CD automation. It can be installed on various platforms, including Linux and Kubernetes.

Why use Kubernetes for GitLab?

Kubernetes helps manage containerized applications like GitLab. It ensures your GitLab instance is scalable and resilient, making it easier to handle large workloads.

What are the prerequisites for installing GitLab on Kubernetes?

Before you start, you need a Kubernetes cluster, a configured DNS, and essential tools like kubectl and Helm. You also need to set up persistent storage and Ingress with TLS.

How do I create a GitLab namespace in Kubernetes?

To create a namespace for GitLab, you can use the command: kubectl create namespace gitlab. This isolates GitLab resources from other applications in your cluster.

How do I access the GitLab web interface after installation?

After installing GitLab, you can access the web interface by retrieving the initial root password and navigating to the GitLab URL configured during setup.

How do I disable user registration in GitLab?

To disable user registration, go to the GitLab web interface, then navigate to settings > general > sign-up restrictions. From there, you can disable sign-ups or limit them based on email domains.

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