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Docker & Kubernetes for Developers · Lesson

Automated Deployments with Kubernetes CD

Set up Continuous Deployment pipelines to automatically deploy new application versions to Kubernetes clusters.

Automated Deployments with Kubernetes CD is a free Docker & Kubernetes for Developers lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Docker & Kubernetes for Developers learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

What is Continuous Deployment?

After building and testing your code, the next step is getting it to users. Continuous Deployment (CD) automates this entire process, from code commit to production deployment, without human intervention.

It's the natural evolution of Continuous Integration (CI), where every successful build that passes all tests is automatically released.

Benefits of Automated K8s CD

Manually deploying to Kubernetes can be complex and error-prone. Automating deployments brings significant advantages:

  • Speed: New features reach users faster.
  • Consistency: Deployments are identical every time.
  • Reliability: Reduces human errors in complex K8s operations.
  • Scalability: Manages deployments across many services and clusters.

A Typical K8s CD Workflow

A basic Continuous Deployment pipeline for Kubernetes usually follows these stages:

  1. Code Commit: Developer pushes code to Git.
  2. CI (Build & Test): Automated build, tests run, Docker image created.
  3. Image Push: New Docker image pushed to a container registry (e.g., Docker Hub).
  4. K8s Manifest Update: Deployment manifest updated with the new image tag.
  5. Apply to Cluster: The updated manifest is applied to the Kubernetes cluster.

How Kubernetes Updates Work

In Kubernetes, you update an application by changing its Deployment manifest. The most common change is updating the Docker image tag to a newer version.

Kubernetes then intelligently manages the transition from the old version to the new one, ensuring your application remains available.

Deployment Manifest Update

Here's a simplified Kubernetes Deployment manifest. To update your application, you simply change the image tag (e.g., from v1.0.0 to v1.0.1) and apply the updated manifest.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: myregistry/my-app:v1.0.0 # Change this tag!
        ports:
        - containerPort: 80

Zero-Downtime Rolling Updates

Kubernetes uses a rolling update strategy by default. When you update a Deployment, it:

  • Gradually replaces old Pods with new ones.
  • Ensures a minimum number of Pods are always running.
  • Avoids downtime by not taking all old Pods down simultaneously.

This ensures a smooth transition to your new application version.

Health Checks for Reliability

For automated deployments, liveness and readiness probes are crucial:

  • Liveness Probe: Tells Kubernetes if your application is still running. If it fails, Kubernetes restarts the Pod.
  • Readiness Probe: Tells Kubernetes if your application is ready to serve traffic. New Pods won't receive traffic until this probe passes.

These prevent unhealthy versions from taking user requests.

Dealing with Failed Deployments

Even with automation, issues can arise. Kubernetes tracks deployment history, allowing for easy rollbacks:

  • If a new version is buggy, you can quickly revert to a previous, stable version.
  • The command kubectl rollout undo deployment/my-app-deployment can revert to the last successful deployment.

This capability is a safety net for CD.

Popular CD Tools Integration

Many CI/CD tools can automate Kubernetes deployments. They often integrate by:

  • Running kubectl commands in pipeline scripts.
  • Using Kubernetes APIs directly.

Examples include Jenkins, GitLab CI/CD, GitHub Actions, and CircleCI. These tools orchestrate the steps from image build to K8s deployment.

Deployment Update Quiz

You've pushed a new Docker image of your application to your registry. What is the most common and direct way to trigger an update for an existing Kubernetes Deployment to use this new image?

CD to Kubernetes: Recap

In this lesson, we explored Continuous Deployment (CD) for Kubernetes. You learned:

  • CD automates application releases.
  • How K8s manages updates using rolling updates.
  • The importance of probes and rollbacks.
  • How CI/CD tools integrate with Kubernetes for automation.

Next, we'll dive deeper into GitOps, a powerful methodology for K8s CD.

Frequently asked questions

Is the “Automated Deployments with Kubernetes CD” lesson free?

Yes — the full text of “Automated Deployments with Kubernetes CD” is free to read here on the web, and the Docker & Kubernetes for Developers course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Docker & Kubernetes for Developers course, upgrade to CoddyKit PRO.

What will I learn in “Automated Deployments with Kubernetes CD”?

Set up Continuous Deployment pipelines to automatically deploy new application versions to Kubernetes clusters. You practise Docker & Kubernetes for Developers with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Docker & Kubernetes for Developers?

No prior experience is required. Docker & Kubernetes for Developers on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Automated Deployments with Kubernetes CD” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Docker & Kubernetes for Developers lesson?

Yes. Every Docker & Kubernetes for Developers lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Integrating Docker into CI Pipelines
  2. Automated Deployments with Kubernetes CD
  3. Introduction to GitOps with Kubernetes
  4. Managing Kubernetes Manifests with Helm Charts
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