How to Pass GitLab CI/CD Variables to Kubernetes (AKS) Deployment.yaml

How to Pass GitLab CI/CD Variables to Kubernetes (AKS) Deployment.yaml

In the world of DevOps, the integration of GitLab’s Continuous Integration/Continuous Deployment (CI/CD) with Kubernetes (AKS) has become a game-changer. This blog post will guide you on how to pass GitLab CI/CD variables to Kubernetes (AKS) deployment.yaml. This is a crucial step in automating your deployment processes, ensuring a seamless and efficient workflow.

Prerequisites

Before we dive in, ensure you have the following:

• A GitLab account with a project set up.
• A Kubernetes cluster on Azure Kubernetes Service (AKS).
• Basic understanding of GitLab CI/CD, Kubernetes, and YAML.

Step 1: Define Your GitLab CI/CD Variables

In your GitLab project, navigate to Settings > CI/CD > Variables. Here, you can define your variables. These could be your Docker image name, Kubernetes namespace, or any other data you want to pass to your Kubernetes deployment.

DOCKER_IMAGE: "my-app-image"
K8S_NAMESPACE: "my-app-namespace"

Step 2: Create Your .gitlab-ci.yml File

The .gitlab-ci.yml file is where you define your CI/CD pipeline. In this file, you’ll specify the stages of your pipeline and the jobs that run at each stage. Here’s a basic example:

stages:
  - build
  - deploy

build:
  stage: build
  script:
    - echo "Building the Docker image..."
    - docker build -t $DOCKER_IMAGE .

deploy:
  stage: deploy
  script:
    - echo "Deploying to Kubernetes..."
    - kubectl apply -f deployment.yaml

Step 3: Modify Your deployment.yaml File

In your deployment.yaml file, you’ll need to use Kubernetes' env field to pass in your GitLab CI/CD variables. Here’s how you can do it:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  template:
    spec:
      containers:
      - name: my-app
        image: $DOCKER_IMAGE
        env:
        - name: DOCKER_IMAGE
          valueFrom:
            fieldRef:
              fieldPath: spec.containers[0].image
        - name: K8S_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace

Step 4: Use envsubst to Substitute Variables

The envsubst command-line tool can substitute the values of environment variables. In your .gitlab-ci.yml file, use envsubst to replace the variables in your deployment.yaml file before applying it:

deploy:
  stage: deploy
  script:
    - echo "Deploying to Kubernetes..."
    - envsubst < deployment.yaml | kubectl apply -f -

Conclusion

By following these steps, you can successfully pass GitLab CI/CD variables to your Kubernetes (AKS) deployment.yaml. This integration not only automates your deployment processes but also enhances the efficiency of your DevOps workflow.

Remember, the key to successful DevOps is continuous learning and adaptation. So, keep exploring, keep learning, and keep innovating!

I hope this guide was helpful. If you have any questions or need further clarification, feel free to leave a comment below. Happy coding!

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