Docker

Use docker help, man dockerfile of man docker-<command> (e.g. man docker-run).

Concepts:

Major components:
- A server/daemon which
  - manages docker objects, such as images, containers, network and data volumes
  - has a REST API
  - and a CLI (which uses the REST API)
- A client which is the primary way to interact with Docker.
- A registry (e.g. Docker Hub) that stores images
App hierarchy:
- Stack
- Service: a container from a docker-compose file
- Container:
  - When stopped: a runnable instance of an image
  - When started: a running image (i.e. image + state)
  - may be connected to a network and/or storage
  - can be stored as an image
- Image:
  - A read-only template with instructions for creating a Docker container
  - an executable package
  - may be based on another image
Files:
- A Dockerfile defines an image
- A docker-compose.yml defines one or more containers (a.k.a. services) that work together
Tips:
- You start a container (after it has been stopped) and run an image (which creates and starts a container).
- Docker services can address each other through their container names as host name.

command (docker …)	effect
`build -t friendlyhello .`	Create image using this directory's Dockerfile
`run -p 4000:80 friendlyhello`	Run "friendlyname" mapping port 4000 to 80
`run -d -p 4000:80 friendlyhello`	Same thing, but in detached mode
`container ls`	List all running containers
`container ls -a`	List all containers, even those not running
`container stop <hash>`	Gracefully stop the specified container
`container kill <hash>`	Force shutdown of the specified container
`container rm <hash>`	Remove specified container from this machine
`container rm $(docker container ls -a -q)`	Remove all containers
`image ls -a`	List all images on this machine
`image rm <image id>`	Remove specified image from this machine
`image rm $(docker image ls -a -q)`	Remove all images from this machine
`login`	Log in this CLI session using your Docker credentials
`tag <image> username/repository:tag`	Tag <image> for upload to registry
`push username/repository:tag`	Upload tagged image to registry
`run username/repository:tag`	Run image from a registry

command (docker …)	effect
`volume rm $(docker volume ls)`	Remove all named volumes
`exec -i -t container_name /bin/bash`	Open a terminal
`system prune`	WARNING: use with caution

command (`docker-compose ...`)	effect
`exec <container_name> bash`	run command `bash`
`-f <file> up`	start from a custom file
`down --volumes`	also remove volumes attached to the container