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This article briefly introduces the relationship between the docker container and the predecessor process, and how to write Dockerfile/docker-compose.yml to make the container run gracefully.

The life cycle of a docker container is related to the antecedent process in the container, which is why we may encounter some containers that run for a few seconds and then automatically end: because there is no resident preprocess in the container, the container exits automatically after the preprocess finishes running.

Like docker hello-world.

# output a bunch of things in a flash docker run-- name hello-world hello-world# can see that the hello-world container has exited docker ps-a

So how can you keep the container from quitting automatically? If we want to log in to a pure container such as alpine/centos/ubuntu, install some service components on top of it, and then make our own image in commit.

There are many ways to create a container by performing an endless loop of while (true) (sleep, of course) or using tail-f / dev/null, for the purpose of starting a preset that can be resident. In fact, we can more elegantly use the interactive and tty parameters of the docker container to open the sh/bash (* nix system must have) command as a pre-command, so that the container does not exit automatically.

For example, use the alpine image as the base image to create a small alpine system container that can be run permanently so that we can log in and execute some commands interactively.

# create a container using alpine system image #-I interactive=true enable stdin#-t tty=true allocation session terminal #-d daemon mode without adding or adding directly into the container requires ctrl+p+q cut out # cannot exit yo Exit is equivalent to ending the sh session and the container exits docker run-it-d-- name alpine alpine sh# alpine must be running docker ps# login container docker exec-it alpine sh# apline using apk as package management # install a small train # later, you can use docker commit-m "alpine with sl cmd"-a "big_cat" alpine big_cat/alpine_sl to generate a new mirror apk add sl# exit container Note:-d start If there is no-d to start the sh terminal that enters directly, you cannot exit, otherwise the container will also exit the exit.

Submit container changes to generate a new image

Docker commit-m "alpine with sl cmd"-a "big_cat" alpine big_cat/alpine_sldocker images# post to docker hub if you have an account docker push big_cat/alpine_sl

# you don't need to specify the-it parameter docker stop alpinedocker start alpine when you stop / start the container later

Submit container changes to generate a new image

Docker commit-m "alpine with sl cmd"-a "big_cat" alpine big_cat/alpine_sldocker images# post to docker hub if you have an account docker push big_cat/alpine_sl

The above command actually uses the sh/bash session terminal as a pre-process so that the container does not exit automatically.

If you think it would be crude to write like this when creating a container, it doesn't matter, we can push it all to docker-compose.

Docker-compose.yml

Version: '3'services: big_cat_alpine: container_name: big_cat_alpine image: alpine stdin_open: true #-i interactive tty: true #-t tty privileged: true entrypoint: ["sh"] # execute sh

Create a container & log in to the container

Docker-compose up-d big_cat_alpine. / docker psdocker exec-it big_cat_alpine sh

Pass those two parameters in through docker-compose, orchestrate and start the service container.

The above is the whole content of this article, I hope it will be helpful to your study, and I also hope that you will support it.

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