Docker has become the de facto standard for containerization among developers and DevOps teams. However, as infrastructure needs grow, so does the need for container orchestration, scaling, self-healing, and centralized management. This is where Kubernetes (k8s) comes into play — a powerful system for managing containerized applications.

Switching from the traditional model of running Docker containers to a full Kubernetes cluster is a strategic decision that requires a clear plan, adaptation of CI/CD processes, and careful migration with minimal downtime. In this article, we’ll explore how to make this transition on your own server or VPS, what tools to use, and how to avoid common pitfalls during migration.

1. Why switch from Docker to Kubernetes?

Limitations of classic Docker:

  • No built-in autoscaling.
  • Challenges with high availability (HA).
  • Managing dozens or hundreds of containers becomes difficult.
  • No native centralized monitoring or logging.

Advantages of Kubernetes:

  • Automatic application scaling.
  • Self-healing containers after failures.
  • Load balancing across pods.
  • Built-in support for secrets, configs, health checks.
  • Integration with Helm, Istio, and CI/CD systems.

2. Migration Plan: Step-by-step Strategy

Step 1: Audit your Docker environment

Take inventory of all running containers:

  • What images are used?
  • What ports are exposed?
  • Are there dependencies between containers?
  • Are volumes (persistent storage) used?
  • Are there environment variables and secrets?

Step 2: Prepare your server or VPS

Choose an environment for deploying your Kubernetes cluster:

  • A VPS server for small clusters or development.
  • Dedicated server for production workloads with heavy traffic.
  • Or colocation if you want full control over the hardware.

Install Kubernetes via kubeadm, k3s, or MicroK8s (for testing purposes).

Step 3: Convert your application to Kubernetes format

Translate your docker run or docker-compose.yml into Kubernetes manifests (.yaml):

  • Deployment
  • Service
  • ConfigMap
  • Secret
  • VolumeClaim

There are tools to help automate this conversion, for example:
kompose convert -f docker-compose.yml

3. Migration Tools

  • Kompose — converts docker-compose to Kubernetes manifests.
  • Skaffold — for local development and cluster deployments.
  • Helm — package manager for Kubernetes: templating and config management.
  • Velero — for backup and restore during migration.
  • Kustomize — for managing layered configuration patches.

4. Minimizing Downtime: How to Migrate Without Losing Access

Option 1: Parallel Deployment

  • Deploy the new Kubernetes environment alongside your existing Docker infrastructure.
  • Perform full testing of all services.
  • Switch DNS or load balancer only after everything is verified.

Option 2: Canary Release

  • Route 10–20% of traffic to the new Kubernetes environment initially.
  • Collect metrics, logs, and user feedback.
  • Gradually migrate all services over.

Option 3: Shadow Traffic

  • Mirror real traffic from the Docker environment to the Kubernetes cluster without affecting users.
  • Analyze service behavior with zero production risk.

5. Rollback Strategies

  • Save backup copies of Docker images (docker save).
  • Preserve your docker-compose.yml and .env files.
  • Use kubectl rollout undo in Kubernetes to revert deployments.
  • Test rollback procedures in isolated environments before going live.
  • If full rollback is needed — re-point DNS or load balancer to the old infrastructure.

6. Common Migration Mistakes

  • Insufficient server resources → cluster instability.
  • No monitoring → lack of visibility and diagnostics.
  • Missing readiness/liveness probes → pods don’t recover correctly.
  • Hardcoded configurations in code → hard to scale or manage.

7. Best Practices for a Reliable Launch

  • Use Ingress controllers to handle routing and traffic.
  • Separate production and development environments (via namespace or clusters).
  • Automate deployment using CI/CD or GitOps.
  • Implement monitoring (Prometheus, Grafana) and logging (Loki, ELK stack).
  • Always back up data (Velero, Restic, snapshots).

Conclusion

Migrating from Docker to Kubernetes is not just a technical switch — it’s a strategic step toward scalability, reliability, and flexible infrastructure management. A successful migration requires planning, the right tools, and a clear rollback path.

By choosing VPS, dedicated servers, or colocation from server.ua, you gain a stable infrastructure foundation ready to support Kubernetes clusters of any scale.