How to clean up resources occupied by docker

Foreword:

Friends who often use docker know that docker occupies resources very quickly. The most obvious and easiest to detect is the occupation of disk space. So how do we clean up the system resources occupied by docker?

(Learning video sharing: Introduction to Programming)

The method is as follows:

View the resources occupied by docker

is cleaning up resources Before we need to figure out what system resources docker occupies. This requires a combination of different commands to accomplish.
docker container ls: By default, only running containers are listed. The -a option will list all containers including stopped ones.
docker image ls: List image information. The -a option will list intermediate images (which are the layers that other images depend on).
docker volume ls: List data volumes.
docker network ls: List network.
docker info: Displays system-level information, such as the number of containers and images, etc.

After checking the resources used by docker through these commands, I believe you have decided to clean up some resources occupied by docker! Let's start with those resources that are not being used.

Only delete those unused resources

Docker provides the convenient docker system prune command to delete stopped containers, dangling images, networks not referenced by containers, and during the build process cache:

$ docker system prune

For security reasons, this command will not delete data volumes that are not referenced by any container by default. If you need to delete these data volumes at the same time, you need to explicitly Specify the --volumns parameter. For example, you may want to execute the following command:

$ docker system prune --all --force --volumes

Not only will the data volume be deleted this time, but there will not even be a confirmation process! Note that using the --all parameter will delete all unreferenced images, not just dangling images.
It is necessary to explain here what dangling images are. In fact, they can be simply understood as images that are not referenced by any image. For example, after you rebuild the image, those previously built image layers that are no longer referenced become dangling images:

After the local image is updated, An image similar to the in the red box in the picture will appear. This means that the old images are no longer referenced, and they become dangling images. If you use the -a parameter, you will also find another type of mirror, whose repository and tag columns both appear as :

## These images are called intermediate images (the layers on which other images depend).

We can also execute prune under different subcommands, so that certain types of resources are deleted:

docker container prune # 删除所有退出状态的容器
docker volume prune # 删除未被使用的数据卷
docker image prune # 删除 dangling 或所有未被使用的镜像

Let docker return to the state during installation

The "status during installation" here refers to the resource usage rather than the related configuration of docker. This is also a relatively common use case. For example, the author needs to automatically restore a production environment on a certain day in a clean docker environment (using the backup data of the production environment) for bug investigation. Let’s take a look at what needs to be done?

Recall the docker system prune --all --force --volumns command we introduced earlier. If all containers in the system have been stopped before executing this command, then this command will remove all resources! Okay, now let's figure out how to stop all the containers in the system.

docker container stop command can stop one or more containers. We only need to list all running containers in the system. Since docker doesn't mind us stopping a stopped container again, let's be simple and rude and directly list all containers (including stopped ones)!

$ docker container ls -a -q

-a displays all containers, -q displays only numeric container IDs.

Then use the execution result of this command as the parameter of the docker container stop command:

$ docker container stop $(docker container ls -a -q)

The complete command to restore the docker environment is as follows:

$ docker container stop $(docker container ls -a -q) && docker system prune --all --force --volumns

Similar to the previous prune command, you can also Completely delete a certain type of resource:

Delete container: docker container rm $(docker container ls -a -q)
Delete image: docker image rm $(docker image ls -a -q)
Delete data Volume: docker volume rm $(docker volume ls -q)
Delete network: docker network rm $(docker network ls -q)

Create shell alias

The above command can be completed The task is tedious, but we can use the shell's alias function to simplify the execution of these commands.

alias docker-clean-unused='docker system prune --all --force --volumes'alias docker-clean-all='docker stop $(docker container ls -a -q) && docker system prune --all --force --volumes'

把上面的命令写入到用户的 ~/.bashrc 文件中就可以了！

执行一次清理任务：

总结

经常清理系统资源不仅能够让系统运行的更流畅，也利于我们把精力集中在相关的重点资源上面。所以建议大家能够使用相关的资源清理命令，让 docker 保持清爽和高效。

相关推荐：docker入门教程

The above is the detailed content of How to clean up resources occupied by docker. For more information, please follow other related articles on the PHP Chinese website!