Explore essential Docker Compose commands and their practical usage with this quiz designed for intermediate users. Enhance your understanding of orchestrating multi-container applications using docker-compose tools, command options, and troubleshooting techniques.
Which docker-compose command would you use to build images before starting containers as described in the docker-compose.yml file, for example when you have updated your service code?
Explanation: The command 'docker-compose up --build' ensures that images are rebuilt before the containers are started, which is crucial after making changes to your code or dependencies. The 'docker-compose run' command is typically used to run a one-time command or task, not the full set of services. 'docker-compose start' only starts already created containers, without building new images. 'docker-compose up -d --force' is incorrect as there is no '--force' flag for 'up'. Only the '--build' flag reliably triggers the build process.
When you want to start services that were previously stopped without recreating their containers, which docker-compose command should you use?
Explanation: The 'docker-compose start' command starts existing containers that were previously stopped, and does not recreate or rebuild them. 'docker-compose up --force-recreate' recreates every container, which is unnecessary if you just want to restart stopped services. 'docker-compose launch' and 'docker-compose init' are not valid docker-compose commands, making them incorrect in this context.
If you need to follow the real-time output of all services in your Compose project to troubleshoot an issue, which command should you use?
Explanation: The 'docker-compose logs --follow' command streams log updates as they are written, which is useful for live troubleshooting across multiple services. 'docker-compose output' is not a recognized command. 'docker-compose inspect' is used for detailed configuration data but not for log streaming. 'docker-compose tail' is not a valid command; the correct option to display and follow logs is 'logs --follow'.
Which docker-compose command should you use to stop all running containers and remove them along with any associated networks, for example when cleaning up after running your application?
Explanation: The 'docker-compose down' command stops all running services and removes containers, networks created by up, and optionally images and volumes. 'docker-compose delete' and 'docker-compose stop --clean' are not valid commands. While 'docker-compose rm --force' removes containers, it does not stop them or remove associated networks. Therefore, 'down' is the only comprehensive solution.
To run a shell command interactively inside a running container managed by docker-compose, such as for debugging purposes, what command would you use?
Explanation: The 'docker-compose exec' command allows you to run an interactive shell or command within a running service container, making it ideal for debugging or inspecting the environment. 'docker-compose access', 'docker-compose bash', and 'docker-compose enter' are not recognized docker-compose commands and thus will not achieve this task. Always use 'exec' for in-container command execution.