Docker Interview Questions and Answers

Ques 6. What is the difference between a Docker image and a Docker container?

An image is a lightweight, standalone, and executable package that includes everything needed to run a piece of software. A container is a runtime instance of a Docker image.

Example:

docker run -d my_image

Ques 7. How do you remove all Docker containers?

You can use the following command to remove all Docker containers: docker rm $(docker ps -a -q)

Example:

docker rm $(docker ps -a -q)

Ques 8. Explain the concept of Docker Volumes.

Docker Volumes are used to persist data generated by and used by Docker containers. They provide a way to share data between containers and persist data even if the container is removed.

Example:

docker run -v /path/on/host:/path/in/container my_image

Ques 9. What is the role of a Dockerfile in Docker?

A Dockerfile is a script that contains a set of instructions to build a Docker image. It defines the base image, adds application code, sets environment variables, and configures the container.

Example:

FROM node:14
WORKDIR /app
COPY . .
RUN npm install
CMD ["npm", "start"]

Ques 10. How does Docker Swarm differ from Kubernetes?

Docker Swarm and Kubernetes are both orchestration tools for managing containerized applications. Kubernetes is more feature-rich and widely adopted, while Docker Swarm is simpler to set up and use for smaller deployments.