Blake Hoerres | 4 months ago | 5 min read

Building a Hybrid CI/CD Pipeline for Homelab Projects

The Spark of Inspiration

It was during a late-night coding session, fueled by an unhealthy amount of coffee, when I had my epiphany. I'd just finished manually deploying yet another project to my homelab infrastructure, and then again to its cloud extension. The process was tedious, error-prone, and frankly, beneath the capabilities of the hybrid environment I'd so painstakingly built.

That's when it hit me: my hybrid homelab was missing a crucial piece – a unified CI/CD pipeline that could seamlessly deploy across both my local infrastructure and cloud services. This realization set me on a journey to automate and streamline my development workflow, bridging the gap between my local tinkering and cloud-scale deployment.

Understanding the Hybrid CI/CD Landscape

Before we dive into the nuts and bolts, let's paint a picture of what a hybrid CI/CD pipeline looks like in a homelab context. Imagine a conveyor belt that starts in your local workshop (your development environment), passes through various quality control stations (CI stages), and then forks off to deliver your polished product to both your local showroom (on-premises deployment) and a global distribution center (cloud deployment).

This approach allows us to:

Maintain a consistent development and deployment process across environments
Leverage cloud resources for intensive testing and building stages
Deploy to multiple targets with a single workflow
Ensure parity between local and cloud deployments
Rapidly iterate and experiment across our entire hybrid infrastructure

Key Components of a Hybrid CI/CD Pipeline:

Version Control System (Git repository)
CI/CD orchestrator (Jenkins, GitLab CI, or cloud-native solutions)
Build and test environments (local and cloud-based)
Artifact storage (local NAS and cloud storage)
Deployment targets (local kubernetes cluster, cloud services)

The Journey to Hybrid CI/CD Nirvana

Step 1: Laying the Groundwork

First, we need to ensure our local and cloud environments are primed for CI/CD integration.

For the local environment:

Set up a Git server (like GitLab or Gitea) or use a cloud-based repository
Ensure your kubernetes cluster or deployment targets are API-accessible

For the cloud environment:

Set up IAM roles and permissions for your CI/CD pipeline
Create necessary storage buckets for artifacts

Step 2: Choosing Your CI/CD Orchestrator

Your choice of CI/CD tool will depend on your specific needs and existing setup. Let's explore a few options:

Jenkins: The Swiss Army knife of CI/CD
Pros: Highly flexible, vast plugin ecosystem
Cons: Can be complex to set up and maintain
GitLab CI: Integrated with GitLab, cloud-agnostic
Pros: Easy to use if you're already using GitLab, built-in container registry
Cons: Can be resource-intensive for self-hosted installations
AWS CodePipeline + Jenkins: A hybrid approach
Pros: Leverages both AWS services and Jenkins' flexibility
Cons: Tighter coupling with AWS

For our example, let's use GitLab CI, as it offers a good balance of features and ease of use for hybrid setups.

Step 3: Crafting Your CI/CD Pipeline

Now, let's create a basic .gitlab-ci.yml file that defines our hybrid pipeline:

stages:
  - build
  - test
  - deploy

variables:
  KUBE_CONFIG: ${KUBE_CONFIG}
  AWS_ACCESS_KEY_ID: ${AWS_ACCESS_KEY_ID}
  AWS_SECRET_ACCESS_KEY: ${AWS_SECRET_ACCESS_KEY}

build:
  stage: build
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker build -t myapp:$CI_COMMIT_SHA .
    - docker push myregistry.com/myapp:$CI_COMMIT_SHA

test:
  stage: test
  image: myapp:$CI_COMMIT_SHA
  script:
    - run_tests.sh

deploy_local:
  stage: deploy
  script:
    - kubectl --kubeconfig <(echo $KUBE_CONFIG | base64 -d) apply -f k8s/
  only:
    - main

deploy_cloud:
  stage: deploy
  image: 
    name: amazon/aws-cli
    entrypoint: [""]
  script:
    - aws eks get-token --cluster-name my-cluster | kubectl apply -f k8s/
  only:
    - main

This pipeline does the following:

Builds a Docker image of our application
Runs tests on the built image
Deploys to our local kubernetes cluster
Deploys to an AWS EKS cluster

Step 4: Integrating Cloud Services

To truly leverage our hybrid setup, let's integrate some cloud services into our pipeline. We'll use AWS as an example, but similar principles apply to other cloud providers.

Use AWS CodeBuild for intensive build jobs:

build:
  stage: build
  image: amazon/aws-cli
  script:
    - aws codebuild start-build --project-name myapp-build --source-version $CI_COMMIT_SHA
    - aws codebuild wait build-completed --id $BUILD_ID

Leverage cloud storage for artifacts:

.push_to_s3: &push_to_s3
  - aws s3 cp ./artifacts s3://my-artifact-bucket/$CI_COMMIT_SHA/ --recursive

build:
  stage: build
  script:
    - build_app.sh
    - *push_to_s3

Use cloud services for enhanced testing:

performance_test:
  stage: test
  script:
    - aws devicefarm create-upload --project-arn $PROJECT_ARN --name performance_test.zip --type APPIUM_JAVA_TESTNG_TEST_PACKAGE
    - aws devicefarm schedule-run --project-arn $PROJECT_ARN --app-arn $APP_ARN --device-pool-arn $DEVICE_POOL_ARN --test $UPLOAD_ARN

Step 5: Monitoring and Observability

A key aspect of any CI/CD pipeline is the ability to monitor and quickly debug issues. For our hybrid setup, we need a solution that can provide visibility across both local and cloud environments.

Set up Prometheus and Grafana for monitoring:

deploy_monitoring:
  stage: deploy
  script:
    - helm upgrade --install prometheus stable/prometheus
    - helm upgrade --install grafana stable/grafana
    - kubectl apply -f monitoring/

Integrate with cloud monitoring services:

.push_logs_to_cloudwatch: &push_logs_to_cloudwatch
  - aws logs create-log-stream --log-group-name myapp-logs --log-stream-name $CI_COMMIT_SHA
  - aws logs put-log-events --log-group-name myapp-logs --log-stream-name $CI_COMMIT_SHA --log-events file://pipeline.log

after_script:
  - *push_logs_to_cloudwatch

Challenges and Lessons Learned

Configuration Management: Keeping configurations in sync between local and cloud environments was initially challenging. Solution: Use Helm charts or kustomize for kubernetes deployments, and leverage AWS Systems Manager Parameter Store for shared configurations.
Security: Ensuring that our CI/CD pipeline had the necessary permissions without overly broad access took some fine-tuning. Solution: Implement the principle of least privilege, using IAM roles and Kubernetes RBAC judiciously.
Cost Management: CI/CD pipelines in the cloud can rack up costs quickly if not managed properly. Solution: Implement job timeouts, use spot instances for build jobs, and regularly review and optimize your pipeline.
Consistency: Maintaining consistency between local and cloud deployments required careful planning. Solution: Use infrastructure-as-code tools like Terraform to define both local and cloud resources.

The Hybrid CI/CD Homelab: A Culinary Analogy

Think of your hybrid CI/CD pipeline as a sophisticated kitchen that serves both a local diner and a chain of restaurants. Your local development environment is the prep kitchen, where chefs (developers) experiment with new recipes. The CI pipeline is your quality control process, where ingredients are measured, flavors are tested, and presentation is perfected.

The local deployment is like serving dishes in your diner – immediate feedback, quick iterations. The cloud deployment, on the other hand, is like distributing your perfected recipes to multiple restaurants, ensuring consistency and scale.

Just as a master chef needs to balance local tastes with broader appeal, your hybrid CI/CD pipeline must cater to both your homelab's unique environment and the standardized world of cloud services.

Conclusion

Building a hybrid CI/CD pipeline for homelab projects is more than just an exercise in automation – it's a transformative step that bridges the gap between small-scale tinkering and professional-grade deployments. It empowers you to innovate faster, maintain consistency across environments, and leverage the best of both local and cloud resources.

As you embark on this journey, remember that the perfect pipeline is not built in a day. Start simple, iterate often, and gradually incorporate more advanced features as your needs evolve. Your homelab is no longer just a local playground – it's a launchpad for ideas that can seamlessly scale from your basement to the cloud.

So, fire up that terminal, start crafting your .gitlab-ci.yml, and watch as your projects flow effortlessly from commit to deployment across your entire hybrid infrastructure. Welcome to the future of homelab DevOps!