Docker compose
Docker Compose is a tool that lets you run more than one container at a time, with links / dependencies between them.
This is often called "Orchestration" because that's a lovely word isn't it. "Plumbing" is a more accurate term, but "Orchestration" sounds better.
Docker Compose's orchestra of containers are defined in a docker compose YAML file (docker-compose.yml).
It is particularly well suited for local development and testing, though it can also be used in production.
In production, alternative "Container Orchestration" techniques such as Kubernetes are more widely used.
To run a docker-compose.yml file
(Assuming you have docker desktop, and it is currently running, and that docker tooling, such as docker-compose is available on the command line)
Navigate to the folder which contains the docker-compose.yml file, and call:
docker-compose up
This will:
- If necessary, download the container images referenced in the compose file.
- Run the images (i.e. start "containers" based on the downloaded images) with the connections and dependencies (the plumbing) as described in the docker compose file. (Sorry I mean the 'orchestration')
To stop the Orchestra of containers, to stop the docker-compose.yml images from running
What goes up, must come down. To stop all those running containers from running, execute the complementary command, "down", like so:
docker-compose down
Override the behaviour of docker-compose.yml by using a docker-compose.override.yml file
When you're writing code, you need to be able to run it locally for development purposes, and later run it perhaps in a test environment, a pre-prod and a production environment.
Here's the dealio with "override.yml". You setup the docker-compose.yml file, as you would like it to be when run in a production environment.
Then, if you wish, you can create a