Of Stack

Use of docker system Command Set

  • 2021-11-10 11:16:27
  • OfStack
Directory docker system df docker system prune docker systemc info (docker info)

docker system currently has four subcommands, which are:

docker system df
docker system events
docker system info
docker system prune

One of the most important commands in docker system is the command docker system prune, which cleans up unused data, including mirrored data and stopped containers

View docker system Help 


[root@localhost ~]# docker system --help

Usage:  docker system COMMAND

Manage Docker

Options:
      --help   Print usage

Commands:
  df          Show docker disk usage
  events      Get real time events from the server
  info        Display system-wide information
  prune       Remove unused data

Run 'docker system COMMAND --help' for more information on a command.
[root@localhost ~]#

docker system df

Provides an overview of the overall disk usage of Docker, including mirroring, containers, and (native) volume. So we can now check how many resources Docker uses at any time. 


[root@localhost ~]# docker system df
TYPE                TOTAL               ACTIVE              SIZE                RECLAIMABLE
Images              10                  6                   2.652GB             1.953GB (73%)
Containers          6                   6                   6.922MB             0B (0%)
Local Volumes       0                   0                   0B                  0B
[root@localhost ~]#

docker system prune

If the previous command shows that docker has taken up too much space, we will start cleaning up. There is a command to arrange 1 cut: 


[root@localhost ~]# docker system prune
WARNING! This will remove:
        - all stopped containers #  Cleaning Stopped Container 
        - all networks not used by at least one container # Clean up unused networks 
        - all dangling images # Clean up obsolete images 
        - all build cache # Clean up the build cache 
Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B
[root@localhost ~]#

According to the warning message, this command will delete all closed containers and dangling images. In the example, the name of the image containing three 1GB random files is occupied, and the name is:, which is an dangling image, so it will be deleted. At the same time, all intermediate images will be deleted.

One step further, use the-a option to do deep cleaning. At this point, we will see more serious WARNING information: 


$ docker system prune -a
WARNING! This will remove:
        - all stopped containers
        - all volumes not used by at least one container
        - all networks not used by at least one container
        - all images without at least one container associated to them
Are you sure you want to continue? [y/N] y
Deleted Images:
untagged: test:latest
deleted: sha256:c515ebfa2...
deleted: sha256:07302c011...
deleted: sha256:37c0c6474...
deleted: sha256:5cc2b6bc4...
deleted: sha256:b283b9c35...
deleted: sha256:8a8b9bd8b...
untagged: alpine:latest
untagged: alpine@sha256:58e1a1bb75db1...
deleted: sha256:4a415e366...
deleted: sha256:23b9c7b43...
Total reclaimed space: 2.151GB

This command will clean up the entire system and will keep only the images containers data volumes and networks that are actually in use so you need to be extra careful. For example, we can't run the prune-a commands in a production environment, because some spare images (for backup, rollback, etc.) are sometimes needed, and if these images are deleted, they need to be downloaded again when running the container.

At this point, all images of unbound containers will be deleted. Since the first prune command deleted all containers, all images (which are not bound to any containers) will be deleted.

docker systemc info (docker info)

The abbreviation of this command docker info is familiar to everyone 


[root@localhost ~]# docker system info
Containers: 6
 Running: 6
 Paused: 0
 Stopped: 0
Images: 49
Server Version: 17.06.2-ce
Storage Driver: overlay
 Backing Filesystem: xfs
 Supports d_type: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins: 
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 6e23458c129b551d5c9871e5174f6b1b7f6d1170
runc version: 810190ceaa507aa2727d7ae6f4790c76ec150bd2
init version: 949e6fa
Security Options:
 seccomp
  Profile: default
Kernel Version: 3.10.0-514.26.2.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 24
Total Memory: 31.21GiB
Name: localhost.localdomain
ID: YTL2:6RWX:IZK6:X4XC:XKMO:WVXD:LXPR:E5GN:GEJB:WIUX:L5YH:PDFB
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
 127.0.0.0/8
Registry Mirrors:
 http://9zkjjecg.mirror.aliyuncs.com/
 https://docker.mirrors.ustc.edu.cn/
Live Restore Enabled: false

[root@localhost ~]#

A detailed explanation

元字符 描述
info
等同于 docker info		 查看整个docker系统的信息
例如 docker system info
例如 docker system info | grep Images
events
等同于 docker events		 获取docker系统实时事件，不包括容器内的。
例如：docker system events �until 1499305500
// 截止到 2017.7.6 01:45:00的操作
例如：docker system events �since 1499305500
// 从 2017.7.6 01:45:00之后的操作
df 整体磁盘的使用情况
例如：docker system df
例如：docker system df -v
prune 清理资源，此操作尤其需要注意。
例如：docker system prune
#包括清理以下的4种，即容器、镜像、数据卷、网络
� all stopped containers
� all volumes not used by at least one container
� all networks not used by at least one container
� all dangling images

例如：docker system prune -a
#包括以下的4种情况，主要和上比较
� all stopped containers
� all volumes not used by at least one container
� all networks not used by at least one container
� all images without at least one container associated to them

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