"Docker vs Kubernetes" is one of those framings that quietly sends people down the wrong road. It sounds like a choice between two competing tools, so teams treat it like a bake-off. It isn't. Docker builds and runs containers. Kubernetes orchestrates a fleet of them. You can happily use one without the other, and most teams should — at least for a while.
The question that actually matters is hiding underneath: do I need an orchestrator yet? That's the one worth thinking about carefully, because the cost of answering "yes" too early is real, and it mostly shows up later, on a Saturday, when you're the one holding the pager.
What each tool actually does
Let me separate the two cleanly, because the confusion causes most of the bad decisions.
Docker (or any OCI-compatible runtime — Podman, containerd, and friends) does two jobs: it builds an image from a Dockerfile, and it runs that image as a container on a host. That's the unit of packaging. When you type this:
