What are some free ways to practice Docker, Kubernetes, and Terraform?

For practice, create small projects from scratch: containerize an application, put it behind a reverse proxy, add a database and persistent storage, then move the whole stack to a local Kubernetes cluster. Break one part at a time and diagnose it from logs and events. Once that feels comfortable, recreate the environment with Terraform and compare the result. A home lab is enough, so the practice can be completely free.

Logs alone generally cannot reproduce a Dockerfile or Compose file accurately. They may reveal commands, image names, dependencies, or runtime errors, but they do not contain the complete build history, layer structure, or configuration. It can be a reasonable curated interview puzzle if the goal is interpreting clues, but it is not representative of how container work normally happens.

Do not assume that every DevOps professional regularly designs custom containers. Many roles focus more on operating existing images, deployment pipelines, configuration, and cloud infrastructure. Interview questions should reflect the actual job, so an unusual exercise is not necessarily evidence that you are missing an essential skill.

A good free setup is to build your own container images with Docker or Podman, then run a lightweight Kubernetes cluster locally with kind or k3s. Use Helm to deploy your images and gradually add complexity. You can also practice troubleshooting by intentionally breaking builds, networking, volumes, health checks, and configuration. I would not force Terraform into this exact exercise; learning deployment workflows with something like Argo can be more useful at first.