Docker Containerization Docker Compose and Multi-Container Applications

Question 1

What is the primary purpose of Docker Compose?

Accepted Answer

Define and run multi-container Docker applications using a single YAML file

Answer

Docker Compose allows you to define all services, networks, and volumes for a multi-container application in a docker-compose.yml file and start everything with a single command.

Question 2

What command starts all services defined in a docker-compose.yml file in detached mode?

Accepted Answer

docker compose up -d

Answer

docker compose up -d starts all services defined in the compose file as background (detached) processes, returning control to the terminal.

Question 3

How do you stop and remove all containers, networks, and default volumes created by Docker Compose?

Accepted Answer

docker compose down

Answer

docker compose down stops all running containers and removes containers and networks created by 'docker compose up'. Use --volumes to also remove named volumes.

Question 4

In a docker-compose.yml file, what does the 'depends_on' key control?

Accepted Answer

The startup order of services, ensuring dependencies start before the dependent service

Answer

depends_on tells Docker Compose to start listed services before the service that declares the dependency, controlling startup order.

Question 5

What Compose file keyword defines environment variables for a service?

Accepted Answer

environment

Answer

The 'environment' key in a service definition sets environment variables that are passed into the container at runtime.

Docker Practice Test

Docker Practice Test

Docker Containerization Docker Compose and Multi-Container Applications