Docker Interview Questions and Answers

Ques 21. What is the purpose of the HEALTHCHECK instruction in a Dockerfile?

The HEALTHCHECK instruction adds a health check to a Docker image. It allows you to define a command to check the health of a running container and provide feedback to Docker.

Example:

HEALTHCHECK --interval=5m --timeout=3s CMD curl -f http://localhost/ || exit 1

Ques 22. How do you pass environment variables to a Docker container?

Environment variables can be passed to a Docker container using the `-e` or `--env` option with the `docker run` command.

Example:

docker run -e MY_VARIABLE=value my_image

Ques 23. Explain the concept of Docker Overlay Network.

Docker Overlay Network is a multi-host network that connects Docker containers using overlay drivers. It enables communication between containers running on different Docker hosts.

Ques 24. What is Docker Registry?

Docker Registry is a storage and distribution system for Docker images. It can be a public registry like Docker Hub or a private registry hosted within an organization.

Ques 25. How do you build a Docker image from a Dockerfile?

You can use the `docker build` command followed by the path to the directory containing the Dockerfile.

Example:

docker build -t my_image:latest .