Thread by @FrancescoCiull4

Lifecycle of Docker containers (Thread)

A diagram with some additional information below about the lifecycle of containers.

This is a simplified version, there are other commands (kill, ...) and other intermediate states

Let's see them:

docker create

Creates a new layer over an image with a writeable container.

It prepares it to run a specific command (the one specified in the Dockerfile)

Useful to set up a configuration so that it is ready to start when needed.

Status of the container: "CREATED"

docker start

Starts one (or more) container.

This command can either be used::
- To start a container just created with the docker create command
- To start a stopped container

docker run

Under the Hood, `docker run` are 2 commands:

docker create+docker start

- a container layer is created on the top of an image
- the container just created is started

It's important to understand this to avoid confusion between docker run/start/create

Docker RUN Common Options:

--name: assign a name
--rm: remove it when it exits
-p: publish ports
-e: set environment variable
-d: run it in the background
--network: connect it to a network
-i: keep stdin open
--mount: set a volume or bind mount
--user: set a user

docker stop

Stop one (ore more) container.

The main process inside the container will receive a SIGTERM, then a SIGKILL after some seconds.

The first signal can be edited:
- using the STOPSIGNAL instruction in the Dockerfile
- using the --stop-signal flag in "docker run"

docker pause

Pause all processes within one (or more) containers, suspending all the processes.

- On Linux, this uses the freezer cgroup.
- On Windows, only Hyper-V containers can be paused.

Usually, the SIGSTOP signal is used to suspend a process.

docker unpause

Unpause all processes within one (or more) container

On Linux, it does this using the freezer cgroup.

It un-suspends all processes in the specified containers.

docker rm

Remove one or more stopped containers

To remove a running container, use the -f (or --force) command

You can also remove anonymous volumes associated with the container with the -v option