Resources

What	Type	Link
Base Commands - Quick Ref	Reference	docs.docker
Compose - getting started	Tutorial	docs.docker
Compose - getting started	Tutorial	fedoraproject
Compose Guide (Heroku)	Guide	Heroku
Example of a YAML config for a complex backend/frontend docker setup	Tutorial	freecodecamp
Devhint Cheatsheet	Reference	devhints.io
Fireship: "Docker in 100 Seconds"	YT Video	YouTube

Basic Commands

What	Command	Helpful Flags
List active containers	docker ps	--all
Restart a container	docker restart {containerName}
Stop a container	docker kill {containerName}
Inspect something	docker inspect {thingIdOrName}
View logs	docker logs {?:containerName}	-f follow -tail --details show extra detail
Execute a command inside a container	docker exec {containerName}	-i interactive -t allocate TTY -d detach
Create volume	docker volume create {options} {volumeName}	--driver (see notes on volume types) --label --name --opt
List volumes	docker volume ls
Drop volume	docker volume rm {volumeName}	-f or --force
Print version	docker version
List images	docker image ls
Pull an image	docker pull {imageName}
Run an image	docker run {imageName} Example: docker run hello-world	--name (give container a short name)
List downloaded images	docker images OR docker image ls	--filter

Note: For most of the commands that take an image name, you can optionally request a specific tag or digest version of an image by using a special suffix. For example, {imageName}:{tag} or {imageName}@sha256:{digestSha}

docker-compose is listed below, in its own section

Docker Compose (aka docker-compose) commands

CLI Overview: https://docs.docker.com/compose/reference/overview/, or use docker-compose --help Composer YML file overview: https://docs.docker.com/compose/compose-file/

There are common flags that can be applied with any subcommand. For example: -f or --file lets you specify a docker .yml file other than the default of docker-compose.yml.

What	Command	Helpful Flags
Test out a config	docker-compose config
Stop containers, without removing	docker-compose stop
Stop and remove containers	docker-compose down	-v: remove named volumes
Build and launch container	docker-compose up	-d (starts in detached mode) --force-recreate --build
Start a specific service	docker-compose run {serviceName}
Removed stopped containers	docker-compose rm	If you don't pass a name, it removes all (like rm *) -v removes the volumes as well. Useful if something is persisting when you don't want it to and need a hard reset. -f : Force
Validate a config without running it	docker-compose config	-q - Quiet mode, only validates true/false without verbose output
Show logs	docker-compose logs	-f follow --tail={#} Tail lines You can also pass the container name - docker-compose logs {containerName}

Docker-Compose syntax and options

• You can use environment values within your docker-compose file (variable substitution)

  • Syntax is ${VARIABLE_NAME} (just like JS template literal), or $VARIABLE_NAME

  • The .env file has to be in the same directory as the docker-compose.yml file (see 1, 2)

    • Depending on your version of docker-compose, you might be able to get around this with either --project-directory (ref) or --env-file (ref), however, I have not had success with either so far

• You can pass environment values to the container itself

  • Full details

    • You can use the env_file option to pass an entire .env file contents to the container
    • Put under environment: but leave off value
    • Pass via docker-compose run -e {VAR}={VAL} {imageName}

Volume types options / drivers

See: https://docs.docker.com/storage/storagedriver/select-storage-driver/

• https://docs.docker.com/storage/storagedriver/select-storage-driver/#docker-desktop-for-mac-and-docker-desktop-for-windows

Type	Description
tmpfs	Temp data, stored in memory, not persisted between sessions
btrfs	Advanced, persisted storage. Requires a bunch of pre-reqs, including Linux Kernel support.
nfs	Shared, persisted storage

How do i...

How do I...

• List active containers

  • docker ps

• Restart a container with changes after a .yml / yaml config chance?

  • Bring up, and force image rebuild:

    • docker-compose up -d --force-recreate --build

  • If you run into issues (changes don't seem to take affect, passwords not working, etc)...

    • Sometimes the volume data will persist, even if you ran docker-compose down -v first.
    • Try finding the volume data directory and running rm -rf on it, then rebuild and start back up

• Get a container IP address

  • docker inspect {containerName}

  • Just IP address:

    • docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_name_or_id
    • Use double quotes if you have issues.
    • Credit: S/O

• Debug a container not starting correctly (die event), or view logs

  • Multiple options for log viewing:

    • See this S/O

      • Summary:

        • Start event logger with docker events& - this kind of does tail
        • Do "thing" - e.g. up, that triggers error
        • You should see error appear in event log
        • Copy error instance ID from event log and use with docker logs {eventId}

    • docker-compose -f {composeFile} logs

      • Use -f to follow
      • Use --tail={#} to tail # of lines
    • docker logs {?:containerName}

• Access BASH inside container

  • docker exec -ti {containerName} bash

    • Use exit to stop
  • You can also try docker attach {containerName} to link console STDIN/STDOUT, but this seems less optimal than exec

• Remove a stubborn network ("error while removing network ... has active endpoints")

  1. Find out what containers are using the network

     • docker inspect {networkName}

  2. Either bring down those containers, or break the connection

     • To break connection(s), use docker network disconnect {networkName} {containerName}

  3. Once you have broken linkage, you should be able to bring down

     • Either re-run down, or manually remove network with docker network rm {networkName}

• Kill *all containers

  • docker ps -q | xargs docker kill

Issues

• PostgreSQL issues with Windows - usually due to permissions issue

  • This is a known issue, and requires using named volumes. Links:

    • https://stackoverflow.com/a/57773731/11447682
    • https://stackoverflow.com/a/55110235/11447682

• Can't remove volume (even with -f or --force): "Error response from daemon: remove {volume}: volume is in use"

  • Try this first:

    • docker-compose down -v (or docker-compose rm -f -v)

  • If the volume is being locked by a container, you can find what is using it:

    • docker ps --filter volume={volume}
  • Try docker system prune, and then remove volumes again

  • As a last ditch effort, you can try restarting the entire Docker service (either via GUI, or CLI), then try removing container

    • Windows: restart via CLI
  • Lots of tips in the responses to this S/O question