docker简介

一、Docker介绍

1.1、什么是docker

Docker是一个开源的应用容器引擎，使用Go语言开发，基于Linux内核的cgroup,namespace,Union FS等技术，对应用进程进行封装隔离，并且独立于宿主机与其他进程，这种运行时封装的状态称为容器。

​ Docker早期版本实现是基于LXC，并进一步对其封装，包括文件系统、网络互联、镜像管理等方面，极大简化了容器管理。从0.7版本以后开始去除LXC,转为自省研发的libcontainer，从1.11版本开始，进一步为使用runC和containerd。

​ Docker理念是将应用及依赖包打包到一个可移植的容器中，可发布到任意Linux发行版Docker引擎上。使用沙箱机制运行程序，程序之间相互隔离。

1.2、docker结构体系

Containerd:是一个简单的守护进程，使用runC管理容器。向Docker Engine提供接口。

Shim:只负责管理一个容器。

runC:是一个轻量级的工具，只用来运行容器。

• Docker Client:客户端
• Docker Daemon:守护进程
• Docker Images:镜像
• Docker Container:容器
• Docker Registry:镜像仓库

1.3、docker内部组件

Namespaces

命名空间，Linux内核提供的一种对进程资源隔离的机制，例如进程、网络、挂载点等资源。

 CGroup

控制组，Linux内核提供的一种限制进程资源的机制；例如CPU、内存等资源。

 UnionFS

联合文件系统，支持将不同位置的目录挂载到同一虚拟文件系统，形成一种分层的模型。

 1.4、什么是容器

 

 

• 对软件和其依赖的标准化打包
• 应用之间相互隔离
• 共享同一个OS Kernel
• 可以运行在很多主流操作系统上

 1.5、容器和虚拟机的区别

 

 

以KVM为例与Docker对比

启动时间

Docker妙级启动，KVM分钟级启动。

轻量级

容器镜像带下通常以M为单位，虚拟机以G为单位。容器资源占用小，要比虚拟机部署更快捷。

 性能

容器共享宿主机内核，系统级虚拟化，占用资源少，没有Hypervisor层开销，容器性能基本接近物理机；
虚拟机需要Hypervisior层支持，虚拟化一些设备，具备完整的GuestOS，虚拟化开销大，因而降低性能，没有容器性能好。

 安全性

由于共享宿主机内核，只是进程级隔离，因此隔离性和稳定性不如虚拟机，容器具有一定权限访问宿主机内核，存在一定安全隐患。

 使用要求

KVM基于硬件的完全虚拟化、需要赢家CPU虚拟化技术支持；
容器共享所主机内核，可运行在主流的Linux发行版，不用考虑CPU是否支持虚拟化技术。

 1.6、docker应用场景

•应用程序打包和发布

•应用程序隔离

•持续集成

•微服务部署

•快速搭建测试环境

•提供PaaS产品（平台即服务）

 二、docker安装

2.1、关闭防火墙

  systemctl stop firewalldsystemctl disable firewalld

 2.2、关闭selinux

vim /etc/selinux/config
SELINUX=disabled	#设置为disabled
reboot	#重启服务器
# 查看selinux状态
[root@server04 ~]# getenforce
Disabled

 2.3、安装所需要的包

yum install -y yum-utils   device-mapper-persistent-data   lvm2

 2.4、配置yum源

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

 2.5、安装docker-ce

yum install docker-ce -y

 2.6、启动

systemctl start docker# 加入开机启动systemctl enable docker

 2.7、运行hello-world

docker run hello-world

 2.8、查看docker版本

[root@server04 ~]# docker info
Client: Docker Engine - CommunityVersion:    24.0.6Context:    defaultDebug Mode: falsePlugins:buildx: Docker Buildx (Docker Inc.)Version:  v0.11.2Path:     /usr/libexec/docker/cli-plugins/docker-buildxcompose: Docker Compose (Docker Inc.)Version:  v2.21.0Path:     /usr/libexec/docker/cli-plugins/docker-composeServer:Containers: 2Running: 0Paused: 0Stopped: 2Images: 2Server Version: 24.0.6Storage Driver: overlay2Backing Filesystem: xfsSupports d_type: trueUsing metacopy: falseNative Overlay Diff: trueuserxattr: falseLogging Driver: json-fileCgroup Driver: cgroupfsCgroup Version: 1Plugins:Volume: localNetwork: bridge host ipvlan macvlan null overlayLog: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslogSwarm: inactiveRuntimes: runc io.containerd.runc.v2Default Runtime: runcInit Binary: docker-initcontainerd version: 61f9fd88f79f081d64d6fa3bb1a0dc71ec870523runc version: v1.1.9-0-gccaecfcinit version: de40ad0Security Options:seccompProfile: builtinKernel Version: 3.10.0-1160.90.1.el7.x86_64Operating System: CentOS Linux 7 (Core)OSType: linuxArchitecture: x86_64CPUs: 4Total Memory: 3.682GiBName: server04ID: be595f37-af7c-486d-aca2-76c3590143f7Docker Root Dir: /var/lib/dockerDebug Mode: falseExperimental: falseInsecure Registries:127.0.0.0/8Registry Mirrors:https://registry.docker-cn.com/Live Restore Enabled: false

 2.9、查看运行了哪些docker

docker run -it nginx    <<== -it前台运行、再打开一个终端用于查看[root@server04 ~]# docker ps
CONTAINER ID   IMAGE     COMMAND                   CREATED          STATUS          PORTS     NAMES
5e17bb7f5848   nginx     "/docker-entrypoint.…"   35 seconds ago   Up 33 seconds   80/tcp    modest_wescoff

 2.10、查看容器信息

[root@server04 ~]# docker inspect 5e17bb7f5848
[{"Id": "5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c","Created": "2023-09-25T16:11:02.449798245Z","Path": "/docker-entrypoint.sh","Args": ["nginx","-g","daemon off;"],"State": {"Status": "running","Running": true,"Paused": false,"Restarting": false,"OOMKilled": false,"Dead": false,"Pid": 2566,"ExitCode": 0,"Error": "","StartedAt": "2023-09-25T16:11:03.170447828Z","FinishedAt": "0001-01-01T00:00:00Z"},"Image": "sha256:61395b4c586da2b9b3b7ca903ea6a448e6783dfdd7f768ff2c1a0f3360aaba99","ResolvConfPath": "/var/lib/docker/containers/5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c/resolv.conf","HostnamePath": "/var/lib/docker/containers/5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c/hostname","HostsPath": "/var/lib/docker/containers/5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c/hosts","LogPath": "/var/lib/docker/containers/5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c/5e17bb7f58482e8921b45559f2ffddb45f3ad192644e5fe50aaac8f2f055cc2c-json.log","Name": "/modest_wescoff","RestartCount": 0,"Driver": "overlay2","Platform": "linux","MountLabel": "","ProcessLabel": "","AppArmorProfile": "","ExecIDs": null,"HostConfig": {"Binds": null,"ContainerIDFile": "","LogConfig": {"Type": "json-file","Config": {}},"NetworkMode": "default","PortBindings": {},"RestartPolicy": {"Name": "no","MaximumRetryCount": 0},"AutoRemove": false,"VolumeDriver": "","VolumesFrom": null,"ConsoleSize": [30,96],"CapAdd": null,"CapDrop": null,"CgroupnsMode": "host","Dns": [],"DnsOptions": [],"DnsSearch": [],"ExtraHosts": null,"GroupAdd": null,"IpcMode": "private","Cgroup": "","Links": null,"OomScoreAdj": 0,"PidMode": "","Privileged": false,"PublishAllPorts": false,"ReadonlyRootfs": false,"SecurityOpt": null,"UTSMode": "","UsernsMode": "","ShmSize": 67108864,"Runtime": "runc","Isolation": "","CpuShares": 0,"Memory": 0,"NanoCpus": 0,"CgroupParent": "","BlkioWeight": 0,"BlkioWeightDevice": [],"BlkioDeviceReadBps": [],"BlkioDeviceWriteBps": [],"BlkioDeviceReadIOps": [],"BlkioDeviceWriteIOps": [],"CpuPeriod": 0,"CpuQuota": 0,"CpuRealtimePeriod": 0,"CpuRealtimeRuntime": 0,"CpusetCpus": "","CpusetMems": "","Devices": [],"DeviceCgroupRules": null,"DeviceRequests": null,"MemoryReservation": 0,"MemorySwap": 0,"MemorySwappiness": null,"OomKillDisable": false,"PidsLimit": null,"Ulimits": null,"CpuCount": 0,"CpuPercent": 0,"IOMaximumIOps": 0,"IOMaximumBandwidth": 0,"MaskedPaths": ["/proc/asound","/proc/acpi","/proc/kcore","/proc/keys","/proc/latency_stats","/proc/timer_list","/proc/timer_stats","/proc/sched_debug","/proc/scsi","/sys/firmware"],"ReadonlyPaths": ["/proc/bus","/proc/fs","/proc/irq","/proc/sys","/proc/sysrq-trigger"]},"GraphDriver": {"Data": {"LowerDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba-init/diff:/var/lib/docker/overlay2/4f78ae5f917ca08bbde77f1ad187042791389068f8263be9221aef4f9a3e09aa/diff:/var/lib/docker/overlay2/7bbeb264406af998971a0ec5938723699549c21762aae769666fdb49aa6651bc/diff:/var/lib/docker/overlay2/6017b041b54f72167c4b957c71a974c1d702e3219cc39e2f2f65c4f00204658a/diff:/var/lib/docker/overlay2/87e2982f0891eaac69d78567aa1e9f2a8febb3b839af2bf7998920f440c9907d/diff:/var/lib/docker/overlay2/ce8dddff3e864f83ab6dd2a171a361dad987cdc65ad9571216002ef1d50f3e88/diff:/var/lib/docker/overlay2/09530dcf8710fdbc06635f6e9f4e64acf3d2cd790d844124752e60b226c6a125/diff:/var/lib/docker/overlay2/4eb51cab29daf0a9426941427e54e4b6e9257678e1358238b13a16f88348a447/diff","MergedDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/merged","UpperDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/diff","WorkDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/work"},"Name": "overlay2"},"Mounts": [],"Config": {"Hostname": "5e17bb7f5848","Domainname": "","User": "","AttachStdin": true,"AttachStdout": true,"AttachStderr": true,"ExposedPorts": {"80/tcp": {}},"Tty": true,"OpenStdin": true,"StdinOnce": true,"Env": ["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","NGINX_VERSION=1.25.2","NJS_VERSION=0.8.0","PKG_RELEASE=1~bookworm"],"Cmd": ["nginx","-g","daemon off;"],"Image": "nginx","Volumes": null,"WorkingDir": "","Entrypoint": ["/docker-entrypoint.sh"],"OnBuild": null,"Labels": {"maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"},"StopSignal": "SIGQUIT"},"NetworkSettings": {"Bridge": "","SandboxID": "f4c582778308d596719d33523236eac2ef77457d181daea2e5fbed907e855eee","HairpinMode": false,"LinkLocalIPv6Address": "","LinkLocalIPv6PrefixLen": 0,"Ports": {"80/tcp": null},"SandboxKey": "/var/run/docker/netns/f4c582778308","SecondaryIPAddresses": null,"SecondaryIPv6Addresses": null,"EndpointID": "cb440654ecf1609aeea7fbd6e13c4f0d51280f5d8ee4ff2330f1a320246f7b06","Gateway": "172.17.0.1","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"IPAddress": "172.17.0.2","IPPrefixLen": 16,"IPv6Gateway": "","MacAddress": "02:42:ac:11:00:02","Networks": {"bridge": {"IPAMConfig": null,"Links": null,"Aliases": null,"NetworkID": "3aca20bdb238ca54726173bf0e92d3973b3f5cb95053800b683aa2639e99a9de","EndpointID": "cb440654ecf1609aeea7fbd6e13c4f0d51280f5d8ee4ff2330f1a320246f7b06","Gateway": "172.17.0.1","IPAddress": "172.17.0.2","IPPrefixLen": 16,"IPv6Gateway": "","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"MacAddress": "02:42:ac:11:00:02","DriverOpts": null}}}}
]

 

[root@server04 ~]# curl -I 172.17.0.2
HTTP/1.1 200 OK
Server: nginx/1.25.2
Date: Mon, 25 Sep 2023 16:14:01 GMT
Content-Type: text/html
Content-Length: 615
Last-Modified: Tue, 15 Aug 2023 17:03:04 GMT
Connection: keep-alive
ETag: "64dbafc8-267"
Accept-Ranges: bytes

 2.11、进入容器

[root@server04 ~]# docker exec -it 5e17bb7f5848 bash
root@5e17bb7f5848:/# ls
bin   docker-entrypoint.d   home   lib64   mnt	 root  srv  usr
boot  docker-entrypoint.sh  lib    libx32  opt	 run   sys  var
dev   etc		    lib32  media   proc  sbin  tmp
root@5e17bb7f5848:/# exit
exit

 三、镜像管理

3.1、镜像是什么

• 一个分层存储的文件
• 一个软件的环境
• 一个镜像可以创建N个容器
• 一种标准化的交付
• 一个不包含Linux内核而又精简的Linux操作系统

镜像不是一个单一的文件，而是有多层构成。我们可以通过docker history <ID/NAME>查看镜像中各层内容及大小，每层对应着Dockerfile中的一条指令。Docker镜像默认存储在/var/lib/docker/<storage-driver>中。

[root@server04 ~]# docker history nginx
IMAGE          CREATED      CREATED BY                                       SIZE      COMMENT
61395b4c586d   5 days ago   /bin/sh -c #(nop)  CMD ["nginx" "-g" "daemon…   0B        
<missing>      5 days ago   /bin/sh -c #(nop)  STOPSIGNAL SIGQUIT            0B        
<missing>      5 days ago   /bin/sh -c #(nop)  EXPOSE 80                     0B        
<missing>      5 days ago   /bin/sh -c #(nop)  ENTRYPOINT ["/docker-entr…   0B        
<missing>      5 days ago   /bin/sh -c #(nop) COPY file:9e3b2b63db9f8fc7…   4.62kB    
<missing>      5 days ago   /bin/sh -c #(nop) COPY file:57846632accc8975…   3.02kB    
<missing>      5 days ago   /bin/sh -c #(nop) COPY file:3b1b9915b7dd898a…   298B      
<missing>      5 days ago   /bin/sh -c #(nop) COPY file:caec368f5a54f70a…   2.12kB    
<missing>      5 days ago   /bin/sh -c #(nop) COPY file:01e75c6dd0ce317d…   1.62kB    
<missing>      5 days ago   /bin/sh -c set -x     && groupadd --system -…   112MB     
<missing>      5 days ago   /bin/sh -c #(nop)  ENV PKG_RELEASE=1~bookworm    0B        
<missing>      5 days ago   /bin/sh -c #(nop)  ENV NJS_VERSION=0.8.0         0B        
<missing>      5 days ago   /bin/sh -c #(nop)  ENV NGINX_VERSION=1.25.2      0B        
<missing>      5 days ago   /bin/sh -c #(nop)  LABEL maintainer=NGINX Do…   0B        
<missing>      5 days ago   /bin/sh -c #(nop)  CMD ["bash"]                  0B        
<missing>      5 days ago   /bin/sh -c #(nop) ADD file:a1398394375faab8d…   74.8MB    
[root@server04 ~]# cd /var/lib/docker
[root@server04 /var/lib/docker]# ls
buildkit    engine-id  network   plugins   swarm  volumes
containers  image      overlay2  runtimes  tmp
[root@server04 /var/lib/docker]# cd overlay2/
[root@server04 /var/lib/docker/overlay2]# ls
09530dcf8710fdbc06635f6e9f4e64acf3d2cd790d844124752e60b226c6a125
12f1fd113a660071b93a2a2fa91ab50fd1be168ef6130ab563fb0cb3dc88bd40
13c917e7c0cf4484a29961b08161654dbc20848becd993cb4d07105d7e8dd7a0
13c917e7c0cf4484a29961b08161654dbc20848becd993cb4d07105d7e8dd7a0-init
2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba
2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba-init
417fab199b09d8d1114518d0ae8e28890221cbb13b7066eeaac09b14bfec6b47
4eb51cab29daf0a9426941427e54e4b6e9257678e1358238b13a16f88348a447
4f78ae5f917ca08bbde77f1ad187042791389068f8263be9221aef4f9a3e09aa
6017b041b54f72167c4b957c71a974c1d702e3219cc39e2f2f65c4f00204658a
7bbeb264406af998971a0ec5938723699549c21762aae769666fdb49aa6651bc
8381dcc4c841c5e9c156e709a55aec14db57fecc48f62bac8dbb76806048f4a2
8381dcc4c841c5e9c156e709a55aec14db57fecc48f62bac8dbb76806048f4a2-init
87e2982f0891eaac69d78567aa1e9f2a8febb3b839af2bf7998920f440c9907d
backingFsBlockDev
ce8dddff3e864f83ab6dd2a171a361dad987cdc65ad9571216002ef1d50f3e88
l
[root@server04 /var/lib/docker/overlay2]# 

 3.2、镜像从哪里来

Docker Hub是由Docker公司负责维护的公共注册中心，包含大量的容器镜像，Docker工具默认从这个公共镜像库下载镜像。地址：https://hub.docker.com/explore

3.3、配置进镜像加速器

https://www.daocloud.io/mirrorcurl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.iosystemctl restart docker

 3.4、镜像与容器的联系

 

如图，容器其实是在镜像的最上面加了一层读写层，在运行容器里文件改动时，会先从镜像里面要写的文件复制到容器自己的文件系统中(读写层)。

如果容器删除了，最上面的读写层也就被删除了，改动也就丢失了。所以无论多少个容器共享一个镜像，所做的写操作都是从镜像的文件系统中复制过来操作的，并不会修改镜像的源文件，这种方式提高磁盘利用率。

若想持久化这些改动，可以通过docker commit将容器保存成一新的镜像。

[root@server04 ~]# docker run -itd nginx
4a29bf71d65abab063f697c7101786ad09be2823e4ade796c4c10cc4eaec0bb0
[root@server04 ~]# docker ps
CONTAINER ID   IMAGE     COMMAND                   CREATED          STATUS          PORTS     NAMES
4a29bf71d65a   nginx     "/docker-entrypoint.…"   4 seconds ago    Up 3 seconds    80/tcp    beautiful_lichterman
ac118f15419c   nginx     "/docker-entrypoint.…"   33 seconds ago   Up 32 seconds   80/tcp    quizzical_wescoff
5e17bb7f5848   nginx     "/docker-entrypoint.…"   13 minutes ago   Up 13 minutes   80/tcp    modest_wescoff
[root@server04 ~]# docker exec -it 5e17bb7f5848 bash
root@5e17bb7f5848:/# ls
bin   dev		   docker-entrypoint.sh  home  lib32  libx32  mnt  proc  run   srv  tmp  var
boot  docker-entrypoint.d  etc			 lib   lib64  media   opt  root  sbin  sys  usr
root@5e17bb7f5848:/# touch nginx.txt
root@5e17bb7f5848:/# exit
exit
[root@server04 ~]# docker inspect 5e17bb7f5848
..."GraphDriver": {"Data": {"LowerDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba-init/diff:/var/lib/docker/overlay2/4f78ae5f917ca08bbde77f1ad187042791389068f8263be9221aef4f9a3e09aa/diff:/var/lib/docker/overlay2/7bbeb264406af998971a0ec5938723699549c21762aae769666fdb49aa6651bc/diff:/var/lib/docker/overlay2/6017b041b54f72167c4b957c71a974c1d702e3219cc39e2f2f65c4f00204658a/diff:/var/lib/docker/overlay2/87e2982f0891eaac69d78567aa1e9f2a8febb3b839af2bf7998920f440c9907d/diff:/var/lib/docker/overlay2/ce8dddff3e864f83ab6dd2a171a361dad987cdc65ad9571216002ef1d50f3e88/diff:/var/lib/docker/overlay2/09530dcf8710fdbc06635f6e9f4e64acf3d2cd790d844124752e60b226c6a125/diff:/var/lib/docker/overlay2/4eb51cab29daf0a9426941427e54e4b6e9257678e1358238b13a16f88348a447/diff","MergedDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/merged","UpperDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/diff","WorkDir": "/var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba/work"},"Name": "overlay2"
...[root@server04 ~]# cd /var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba
[root@server04 /var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba]# ls
diff  link  lower  merged  work
[root@server04 /var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba]# ls diff　　<<==与镜像差异
etc  nginx.txt  root  run  var
[root@server04 /var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba]# ls merged/　　<<==Nginx工作的数据驱动存储
bin   dev                  docker-entrypoint.sh  home  lib32  libx32  mnt        opt   root  sbin  sys  usr
boot  docker-entrypoint.d  etc                   lib   lib64  media   nginx.txt  proc  run   srv   tmp  var
[root@server04 /var/lib/docker/overlay2/2f69c7685d3203344082158551d1b6a5800836b31e5170747ba904178939daba]# ls work
work

 3.5、管理镜像常用命令

docker image --help

 

 

 

下载镜像
docker pull nginx //下载镜像
docker pull nginx:v1.4.14运行镜像
docker run -it nginx //运行镜像
docker run -it --rm ubuntu:18.04 bash // 运行镜像并进入shell 退出后删除镜像
docker run --name webserver -d -p 80:80 nginx // 运行镜像，--name 给镜像取一个名字 -d 后台运行模式 -p 镜像端口映射镜像帮助信息
docker image --help // 获取镜像操作的命令帮助搜索镜像
docker search nginx // 搜索nginx镜像查看镜像历史信息
docker image history nginx // 查看镜像历史查看镜像详细信息
docker image inspect nginx //查看镜像详细信息列出镜像
docker images //列出镜像
docker image ls //列出镜像
docker image ls -a //docker image ls 命令列表中只显示顶层镜像。-a 参数可以显示包括中间层在内的所有镜像
docker image ls nginx //根据仓库名列出镜像
docker image ls nginx:v2 //根据某个特定标签列出镜像
docker image ls -f since=mongo:3.2 //mongo:3.2 之后建立的镜像 before 之前
docker image ls -f label=dev //列出标签是dev的镜像
docker images -q -f reference='eshop/*:dev' // 根据名称和标签匹配并只显示id
docker image ls --format "{{.ID}}: {{.Repository}}" // 模板语法查看镜像、容器、数据卷大小
docker system df //查看镜像、容器、数据卷所占的空间大小删除镜像
docker image rm centos:v7 // 按照标签tag删除镜像，也可以根据image id删除
//删除镜像的前提是该镜像没有运行成容器；docker image rm 等同docker rmi命令；如果需要强行删除已经运行为容器的镜像，可以使用-f选项来指定；
docker image rm af34 //根据ID删除镜像，一般取前3个字符或以上就可以了
docker image rm $(docker image ls -q nginx) //过滤删除命令。删除所有仓库名为 nginx 的镜像
docker image rm $(docker image ls -q -f before=nginx:v2)  
docker image rm $(docker images -q -f reference='eshop/*:dev') //-f
docker image prune //删除虚悬镜像给镜像打tag
docker tag centos centos:v6.7 //给镜像打标签 tag

 四、容器管理

4.1、创建容器常用选项

docker container run --help

 

4.2、容器资源限制

 

示例：

内存限额