Docker compose allows orchestration of multiple containers. It allows you to store and run parameters against those containers without typing each time.

Resources

Requirements

You need the following:

  • Dockerfile
    • You could actually skip this if you use a prebuilt Ubuntu image for example but typically you’ll use Dockerfile with docker-compose.
    • You can have multiple Dockerfile files in different folders or within differ names. These each get used by the next part.
  • docker-compose.yml
    • Single config file for one or more containers
    • Allows configuration of volumes, port numbers, network settings, etc.

When you run this, it will use the two files above.

$ docker-compose COMMAND

Build

Initial build

Build images.

$ docker-compose build

Start containers. If the above step was skipped, the build will happen now.

$ docker-compose up

If the container has a long-running task like a server, it will stay up. Stop it with CTRL+C.

Or it will exit immediately.

$ docker-compose up
Starting foo_bar_1 ... done
Attaching to foo_bar_1

Start containers again.

$ docker-compose up

This will not rebuild the image. Continue below.

Rebuild

Add the latest code to the image by forcing a build.

This is necessary as up alone will not rebuild, even if you delete the containers.

$ docker-compose build
$ docker-compose up

Or in one command.

$ docker-compose up --build

Start

As main process

$ docker-compose up

Stop it with CTRL+C.

As background process

Start using -d for daemon.

$ docker-compose up -d

Stop the containers - this can be done from another terminal tab if needed.

$ docker-compose stop

Using run command

If you container exited immediately when using up, you could use run instead, against the name of a service listed in docker-compose.yml.

$ docker-compose run SERVICE
$ # e.g.
$ docker-compose run foo

If you have no commands specified in the Dockerfile, this will start an interactive shell session in teh container.

You can exit with exit command or hit CTRL+D.

Your container will be stopped but kept.

When you use run again using the command aboeb, it will spin up a new container under a new ID.

You can add --rm command to delete the container each time. Note you will lose data in the container unless you persist in a volume.

$ docker-compose run --rm SERVICE

See docker-compose run docs.

Usage:
    run [options] [-v VOLUME...] [-p PORT...] [-e KEY=VAL...] [-l KEY=VALUE...]
        SERVICE [COMMAND] [ARGS...]

Using exec command

Run a command against an already running container. This avoids spinning up duplicate containers, but may not be practical if you container doesn’t have a command to keep it running.

See docker-compose exec docs.

This is the equivalent of docker exec. With this subcommand you can run arbitrary commands in your services.

Usage:

Usage: exec [options] [-e KEY=VAL...] SERVICE COMMAND [ARGS...]

$ docker-compose exec SERVICE COMMAND

Example of using web service with interactive prompt, as recommended in docs:

$ docker-compose exec web sh

Delete

Stop and delete containers. Warning - you will lose any data in the container.

docker-compose down

Choose config

$ docker-compose -f "docker-compose.yml" ARGS

Usage

See the link at the top of this page for CLI usage info or see below.

Man page

$ docker-compose --help

Define and run multi-container applications with Docker.

Usage:
  docker-compose [-f <arg>...] [options] [COMMAND] [ARGS...]
  docker-compose -h|--help

Options:
  -f, --file FILE             Specify an alternate compose file
                              (default: docker-compose.yml)
  -p, --project-name NAME     Specify an alternate project name
                              (default: directory name)
  --verbose                   Show more output
  --log-level LEVEL           Set log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
  --no-ansi                   Do not print ANSI control characters
  -v, --version               Print version and exit
  -H, --host HOST             Daemon socket to connect to

  --tls                       Use TLS; implied by --tlsverify
  --tlscacert CA_PATH         Trust certs signed only by this CA
  --tlscert CLIENT_CERT_PATH  Path to TLS certificate file
  --tlskey TLS_KEY_PATH       Path to TLS key file
  --tlsverify                 Use TLS and verify the remote
  --skip-hostname-check       Don't check the daemon's hostname against the
                              name specified in the client certificate
  --project-directory PATH    Specify an alternate working directory
                              (default: the path of the Compose file)
  --compatibility             If set, Compose will attempt to convert keys
                              in v3 files to their non-Swarm equivalent
  --env-file PATH             Specify an alternate environment file

Commands:
  build              Build or rebuild services
  config             Validate and view the Compose file
  create             Create services
  down               Stop and remove containers, networks, images, and volumes
  events             Receive real time events from containers
  exec               Execute a command in a running container
  help               Get help on a command
  images             List images
  kill               Kill containers
  logs               View output from containers
  pause              Pause services
  port               Print the public port for a port binding
  ps                 List containers
  pull               Pull service images
  push               Push service images
  restart            Restart services
  rm                 Remove stopped containers
  run                Run a one-off command
  scale              Set number of containers for a service
  start              Start services
  stop               Stop services
  top                Display the running processes
  unpause            Unpause services
  up                 Create and start containers
  version            Show the Docker-Compose version information