Comparisons
Docker vs Kubernetes: What's the Difference?
This is one of the most common points of confusion for people new to containers -- Docker and Kubernetes aren't really competitors, they solve different layers of the same problem.
Side-by-Side Comparison
| Docker | Kubernetes |
|---|---|
| Builds and runs individual containers | Orchestrates many containers across many machines |
| Answers: "how do I package this app?" | Answers: "how do I run this reliably at scale?" |
| A single machine's worth of containers, typically | A cluster of machines working together |
| Simple to start with, minimal setup | Real operational complexity to run and maintain |
How They Actually Work Together
In a typical production setup, you build your application into a Docker image, push it to a registry, and Kubernetes pulls that same image to run many instances of it across a cluster -- restarting failed ones, scaling the count up or down, and routing traffic to healthy instances. You need Docker (or a compatible container runtime) regardless of whether you're using Kubernetes; Kubernetes just adds a management layer on top once you have more containers than makes sense to run and babysit manually.
Frequently Asked Questions
Usually not -- for a single container or a small number running on one machine, plain Docker (or Docker Compose for multi-container local setups) is simpler and sufficient. Kubernetes earns its complexity once you need automatic scaling, self-healing, and orchestration across multiple machines.
Not really recommended -- Kubernetes assumes you already understand what a container image is and how to build one well. Learning Docker fundamentals first, as covered in our DevOps and cloud roadmaps, makes Kubernetes concepts click much faster.