Docker Interview Questions and Answers
Ques 1. What is Docker?
Docker is a containerization platform that allows developers to package, distribute, and run applications in isolated environments called containers.
Example:
docker run -d -p 80:80 nginx
Ques 2. Explain the difference between an image and a container.
An image is a lightweight, standalone, and executable package that includes everything needed to run a piece of software. A container is an instance of a running image.
Example:
docker create my_image
Ques 3. What is the purpose of Dockerfile?
Dockerfile is a script that contains instructions for building a Docker image. It specifies the base image, application code, dependencies, and other configurations.
Example:
FROM ubuntu
RUN apt-get update && apt-get install -y nginx
Ques 4. How do you link containers in Docker?
Docker provides network options like --link and user-defined networks to connect containers. The --link option is now considered legacy, and user-defined networks are recommended.
Example:
docker network create my_network
docker run --network my_network --name container1 my_image1
docker run --network my_network --name container2 my_image2
Ques 5. Explain Docker Compose.
Docker Compose is a tool for defining and running multi-container Docker applications. It uses a YAML file to configure the application's services, networks, and volumes.
Example:
version: '3'
services:
web:
image: nginx
ports:
- '80:80'
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