Docker vs Kubernetes: When to Use Each
Docker packages your app into a container. Kubernetes runs hundreds of containers across servers. Not competitors — different problems.
Docker
- Build images, run isolated processes
- Docker Compose for local multi-container dev
- Single-host scope, low complexity
Kubernetes
- Orchestrate containers across clusters
- Self-healing, auto-scaling, rolling updates
- Service discovery, load balancing, secrets
| Feature | Docker | Kubernetes |
|---|---|---|
| Purpose | Build/run containers | Orchestrate at scale |
| Scope | Single host | Multi-host cluster |
| Scaling | Manual | Automatic |
| Complexity | Low | High |
Use Docker alone for:
Local dev, single-server apps, CI/CD, MVPs
Use Kubernetes for:
High availability, auto-scaling, 10+ microservices, multi-team deploys
Career path:
Month 1-2: Docker. Month 3-4: K8s concepts. Month 5+: CKA cert.
FAQ
Is Docker going away?
No. Docker images are the standard. K8s deprecated Dockershim but images still work.
Need K8s for small projects?
Almost never. Docker Compose is enough.
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