https://docs.docker.com 文档
https://hub.docker.com 仓库
docker基本组成镜像（image）
docker镜像是哟个模板，可以通过这个模板来创建容器服务
容器（container）
docker利用容器技术，独立运行一个或一个组应用，通过镜像来创建
启动、停止、删除
docker是个简易linux系统
仓库（repository）
仓库是放镜像的地方、
仓库分为公有仓库和私有仓库，docker hub 默认是国外的仓库
安装 环境查看[root@localhost /]# cat /etc/redhat-release CentOS Linux release 8.5.2111 [root@localhost /]# cat /etc/os-release NAME="CentOS Linux" VERSION="8" ID="centos" ID_LIKE="rhel fedora" VERSION_ID="8" PLATFORM_ID="platform:el8" PRETTY_NAME="CentOS Linux 8" ANSI_COLOR="0;31" CPE_NAME="cpe:/o:centos:centos:8" HOME_URL="https://centos.org/" BUG_REPORT_URL="https://bugs.centos.org/" CENTOS_MANTISBT_PROJECT="CentOS-8" CENTOS_MANTISBT_PROJECT_VERSION="8" [root@localhost /]#帮助文档
#1、卸载旧版本
yum remove docker
docker-client
docker-client-latest
docker-common
docker-latest
docker-latest-logrotate
docker-logrotate
docker-engine
#2、需要安装的包
sudo yum install -y yum-utils
#3、设置镜像仓库
sudo yum-config-manager
--add-repo
https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo #阿里云推荐
https://download.docker.com/linux/centos/docker-ce.repo #默认是国外的
#4、安装docker相关 docker-ce 社区 ee 企业版
yum install docker-ce docker-ce-cli containerd.io
#5、启动daocker
systemctl start docker
#6、使用docker version 检测安装
[root@localhost /]# docker version
Client: Docker Engine - Community
Version: 20.10.14
API version: 1.41
Go version: go1.16.15
Git commit: a224086
Built: Thu Mar 24 01:47:44 2022
OS/Arch: linux/amd64
Context: default
Experimental: true
Server: Docker Engine - Community
Engine:
Version: 20.10.14
API version: 1.41 (minimum version 1.12)
Go version: go1.16.15
Git commit: 87a90dc
Built: Thu Mar 24 01:46:10 2022
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.5.11
GitCommit: 3df54a852345ae127d1fa3092b95168e4a88e2f8
runc:
Version: 1.0.3
GitCommit: v1.0.3-0-gf46b6ba
docker-init:
Version: 0.19.0
GitCommit: de40ad0
[root@localhost /]#
#7、运行 hello world
sudo docker run hello-world
#8、查看下载hello world 的image [root@localhost /]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE docker/getting-started latest bd9a9f733898 7 weeks ago 28.8MB hello-world latest feb5d9fea6a5 6 months ago 13.3kB #9、卸载 卸载依赖 yum remove docker-ce docker-ce-cli containerd.io 删除资源 rm -rf /var/lib/docker #默认工作路径 rm -rf /var/lib/containerd阿里云镜像加速
(3条消息) docker配置阿里云镜像加速器_奕奕星空的博客-CSDN博客_云加速器
#报错 可以重启系统
底层原理docker是怎么工作的？
Docker 是C/S结构系统，docker 的守护进程运行在主机上。通过Socket从客户端的访问，Server端接收到Docker-Client的指令，就回去执行这个命令。
Docker为什么比VM块？
1、Docker有着比虚拟机更少的抽象层。
2、docker 利用的是宿主机的内核。vm需要的guest os。
Docker常用命令https://docs.docker.com/engine/reference/commandlin #文档
帮助命令docker version #显示版本信息 docker info #显示docker的系统信息。包括镜像和容器数量 docker 命令 --help #帮助命令镜像命令
docker images 查询本地镜像
docker images [OPTIONS] [REPOSITORY[:TAG]] #查看所有本地主机上的镜像 [root@localhost /]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE hello-world latest feb5d9fea6a5 6 months ago 13.3kB #解释 REPOSITORY 镜像的仓库源 TAG 镜像的标签 MAGE ID 镜像的ID CREATED 镜像的创建时间 SIZE 镜像的大小 #可选项 Options: -a, --all #列出所有镜像 -q, --quiet #只显示ID
docker search 搜索镜像
docker search [OPTIONS] TERM #搜索镜像 #可选项，通过搜索来过滤 --filter=STARS=3000
docker pull 下载镜像
docker pull 镜像名[:tag] #下载镜像
[root@localhost docker]# docker pull centos
Using default tag: latest # 默认使用最新的
latest: Pulling from library/centos
[root@localhost docker]# docker pull mysql:5.7
5.7: Pulling from library/mysql # 下载源
72a69066d2fe: Pull complete #分层下载
93619dbc5b36: Pull complete
99da31dd6142: Pull complete
626033c43d70: Pull complete
37d5d7efb64e: Pull complete
ac563158d721: Pull complete
d2ba16033dad: Pull complete
0ceb82207cd7: Pull complete
37f2405cae96: Pull complete
e2482e017e53: Pull complete
70deed891d42: Pull complete
Digest: sha256:f2ad209efe9c67104167fc609cca6973c8422939491c9345270175a300419f94 #签名
Status: Downloaded newer image for mysql:5.7
docker.io/library/mysql:5.7 #真实地址
#等价命令
docker pull mysql：5.7
docker pull docker.io/library/mysql:5.7
Options:
-a, --all-tags Download all tagged images in the repository
--disable-content-trust Skip image verification (default true)
--platform string Set platform if server is multi-platform capable
-q, --quiet Suppress verbose output
[root@localhost /]#
docker rmi 删除镜像
docker rmi [OPTIONS] IMAGE_ID IMAGE_ID ……
-f, --force Force removal of the image
--no-prune Do not delete untagged parents
[root@localhost ~]# docker rmi -f feb5d9fea6a5 # 删除指定镜像
[root@localhost ~]#docker rmi -f $(docker images -qa) #删除全部镜像
容器命令
说明:有镜像才可以创建容器
docker pull centos
新建容器并启动
docker run [可选参数] image_id #参数说明 --name="Name" 容器名字 nginx1、nginx2 -d 后台运行方式 -it 使用交互方式运行，进入容器查看内容 -p 指定容器的端口 -p 8080:8080 -o ip：主机端口：容器端口 -p 主机端口：容器端口（常用） -p 容器端口 容器端口 -p 随机端口 #测试 启动并进入容器 [root@localhost docker]# docker run -it centos /bin/bash [root@84ead1d9d6e0 /]# ls #基础版本 很多命令不完善 bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin [root@84ead1d9d6e0 /]#exit #退出
列出运行的容器
[root@localhost /]# docker ps # 列出当前运行的容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES [root@localhost /]# docker ps -a # 列出历史运行的容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 84ead1d9d6e0 centos "/bin/bash" 2 minutes ago Exited (0) About a minute ago heuristic_rubin [root@localhost /]# docker ps -n=1 #列出最近创建的容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 84ead1d9d6e0 centos "/bin/bash" 9 minutes ago Exited (0) 7 minutes ago heuristic_rubin [root@localhost /]# docker ps -aq #只显示镜像ID 84ead1d9d6e0
退出容器
exit #直接退出停止容器 Ctrl + P + Q #容器不停止退出
删除容器
docker rm 容器ID #删除指定容器 docker rm -f $(docker ps -aq) #删除所有容器 docker ps -aq | xargs docker rm
启动和停止
docker start 容器ID docker restart 容器ID docker stop 容器ID docker kill 容器ID #强制停止容器常用的其他命令 后台启动命令
#命令 docker run -d images [root@localhost /]# docker run -d centos #问题docker ps ，发现 centos 停止了 #常见的坑：docker 容器使用后台云心，就必须有一个前台进程，docker 发现没有前台应用就会自动停止 #nginx 容器启动后 发现自己没有提供服务 就会立刻停止查看日志
docker logs -t -f --tail 容器ID #脚本 [root@localhost /]docker run -d centos /bin/bash -c "while true;do ping baidu.com;done" [root@localhost /]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 39b952d20d33 centos "/bin/bash -c 'while…" 12 minutes ago Up 12 minutes lucid_sanderson #-tf 显示日志 --tail 显示条数 [root@localhost /]docker logs -tf --tail 10 39b952d20d33
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查看容器的进程信息#docker top 容器ID [root@localhost /]# docker top 39b952d20d33 UID PID PPID C STIME TTY TIME CMD root 38940 38920 0 02:21 ? 00:00:00 /bin/bash -c while true;do root 38967 38940 0 02:21 ? 00:00:00 ping baidu.com查看镜像的源数据
#命令
docker inspect 容器ID
[root@localhost ~]# docker inspect --help
Usage: docker inspect [OPTIONS] NAME|ID [NAME|ID...]
Return low-level information on Docker objects
Options:
-f, --format string Format the output using the given Go template
-s, --size Display total file sizes if the type is container
--type string Return JSON for specified type
[root@localhost ~]# docker inspect 39b952d20d33
[
{
"Id": "39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278",
"Created": "2022-04-05T18:21:04.893070851Z",
"Path": "/bin/bash",
"Args": [
"-c",
"while true;do ping baidu.com;done"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 38940,
"ExitCode": 0,
"Error": "",
"StartedAt": "2022-04-05T18:21:05.429467757Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:5d0da3dc976460b72c77d94c8a1ad043720b0416bfc16c52c45d4847e53fadb6",
"ResolvConfPath": "/var/lib/docker/containers/39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278/hostname",
"HostsPath": "/var/lib/docker/containers/39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278/hosts",
"LogPath": "/var/lib/docker/containers/39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278/39b952d20d33c9671a6fcad9748c1ee93c0b01cd6ac7b578baff1ecc76fda278-json.log",
"Name": "/lucid_sanderson",
"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,
"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",
"ConsoleSize": [
0,
0
],
"Isolation": "",
"CpuShares": 0,
"Memory": 0,
"NanoCpus": 0,
"CgroupParent": "",
"BlkioWeight": 0,
"BlkioWeightDevice": [],
"BlkioDeviceReadBps": null,
"BlkioDeviceWriteBps": null,
"BlkioDeviceReadIOps": null,
"BlkioDeviceWriteIOps": null,
"CpuPeriod": 0,
"CpuQuota": 0,
"CpuRealtimePeriod": 0,
"CpuRealtimeRuntime": 0,
"CpusetCpus": "",
"CpusetMems": "",
"Devices": [],
"DeviceCgroupRules": null,
"DeviceRequests": null,
"KernelMemory": 0,
"KernelMemoryTCP": 0,
"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/overlay2/40a0f78a2b1de997b3f2af1897968b372fe6594c8236c33e091b8c5537c5c64b-init/diff:/var/lib/docker/overlay2/1fb6cbbaf813f00194bdb7ae04422e7aa31753a3ebe91d9f5f88fa54a04c2e16/diff",
"MergedDir": "/var/lib/docker/overlay2/40a0f78a2b1de997b3f2af1897968b372fe6594c8236c33e091b8c5537c5c64b/merged",
"UpperDir": "/var/lib/docker/overlay2/40a0f78a2b1de997b3f2af1897968b372fe6594c8236c33e091b8c5537c5c64b/diff",
"WorkDir": "/var/lib/docker/overlay2/40a0f78a2b1de997b3f2af1897968b372fe6594c8236c33e091b8c5537c5c64b/work"
},
"Name": "overlay2"
},
"Mounts": [],
"Config": {
"Hostname": "39b952d20d33",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/bash",
"-c",
"while true;do ping baidu.com;done"
],
"Image": "centos",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {
"org.label-schema.build-date": "20210915",
"org.label-schema.license": "GPLv2",
"org.label-schema.name": "CentOS Base Image",
"org.label-schema.schema-version": "1.0",
"org.label-schema.vendor": "CentOS"
}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "f0f4e4d7c22cad51c1f6bbcc455a42ece6d208551c61587ac00c553d3e58a339",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {},
"SandboxKey": "/var/run/docker/netns/f0f4e4d7c22c",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "0b799b7071838712d21071d6245983e02709a8d727f6577979ec0f230893b361",
"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": "19eebba27026f51f10a5240fdcdc81de5f96d51abcf6035b543b3ce574d2c8c9",
"EndpointID": "0b799b7071838712d21071d6245983e02709a8d727f6577979ec0f230893b361",
"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
}
}
}
}
]
进入当前运行的容器
#进入后台的运行的容器 #命令 docker exec -it 39b952d20d33 bashShell [root@localhost ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 39b952d20d33 centos "/bin/bash -c 'while…" About an hour ago Up About an hour [root@localhost ~]# docker exec -it 39b952d20d33 /bin/bash #docker attach 容器ID #测试 [root@localhost ~]# docker attach 39b952d20d33 From 39b952d20d33 (172.17.0.2) icmp_seq=3680 Destination Host Unreachable #docker exec # 进入容器后开启一个终端 #docker attach #进入容器当前运行的终端从容器拷贝文件到宿主机
docker cp 容器id：容器路径 #在容器内新建文件 [root@0372e62cc26f /]# touch dockercp.txt [root@0372e62cc26f /]# ls bin dockercp.txt home lib64 media opt root sbin sys usr dev etc lib lost+found mnt proc run srv tmp var [root@0372e62cc26f /]# docker cp 0372e62cc26f /dockercp.txt /root #将容器内的文件拷贝出来 [root@localhost ~]# docker cp 0372e62cc26f:/dockercp.txt /root [root@localhost ~]# ls anaconda-ks.cfg dockercp.txt ll test test1 testdir testdirln testln testln1 [root@localhost ~]#小结
在仓库搜索镜像
下载镜像
[root@localhost ~]# docker pull nginx Using default tag: latest latest: Pulling from library/nginx a2abf6c4d29d: Pull complete a9edb18cadd1: Pull complete 589b7251471a: Pull complete 186b1aaa4aa6: Pull complete b4df32aa5a72: Pull complete a0bcbecc962e: Pull complete Digest: sha256:0d17b565c37bcbd895e9d92315a05c1c3c9a29f762b011a10c54a66cd53c9b31 Status: Downloaded newer image for nginx:latest docker.io/library/nginx:latest [root@localhost ~]#
运行镜像
docker run -d --name nginx01 -p 3344:80 nginx e1207663d7cecb3090bd35debcad2d47a5d0a54c1f6a2d441700ba2bba4135ec
验证
[root@localhost ~]# curl localhost:3344Welcome to nginx! Welcome to nginx!If you see this page, the nginx web server is successfully installed and working. Further configuration is required.
For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.Thank you for using nginx.
进入容器
[root@localhost ~]# docker exec -it e1207663d7ce /bin/bash root@e1207663d7ce:/#安装tomcat
#官方使用 docker run -it --rm tomcat:9.0 #用完即删除 #下载 docker pull tomcat #启动运行 docker run -d -p 3355:8080 --name tomcat01 tomcat
#进入容器 [root@localhost ~]# docker exec -it tomcat01 /bin/bash #linux 命令缺少 没有站点 #复制站点 root@139163325a5a:/usr/local/tomcat# cp -r webapps.dist/* webapps安装ES+kibana
#ES暴露端口多、占用资源多、数据单独挂载、
docker run -d --name elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" elasticsearch:8.1.2
#启动之后 Linux 非常卡
docker stats
#启动之后迅速关闭
docker stop e927e55d379c
#验证
[root@localhost ~]# curl localhost:9200
{
"name" : "fHjbm--",
"cluster_name" : "elasticsearch",
"cluster_uuid" : "kaCC5NXXTEKq87wd6TRJlQ",
"version" : {
"number" : "5.6.12",
"build_hash" : "cfe3d9f",
"build_date" : "2018-09-10T20:12:43.732Z",
"build_snapshot" : false,
"lucene_version" : "6.6.1"
},
"tagline" : "You Know, for Search"
}
[root@localhost ~]# docker stats
CONTAINER ID NAME CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O PIDS
e927e55d379c elasticsearch 0.11% 1.209GiB / 1.748GiB 69.17% 1.5kB / 729B 769MB / 49.2kB 39
#-e 配置使用的内存
docker run -d --name elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" -e ES_JAVA_OPTS="-Xms64m -Xmx512M" elasticsearch
CONTAINER ID NAME CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O PIDS
2bac80f883af elasticsearch02 0.23% 244.1MiB / 1.748GiB 13.63% 766B / 0B 144MB / 67.6kB 36
[root@localhost ~]# curl localhost:9200
{
"name" : "ZS50Q_Z",
"cluster_name" : "elasticsearch",
"cluster_uuid" : "acXTAtDESFSxl2eA2ok1QA",
"version" : {
"number" : "5.6.12",
"build_hash" : "cfe3d9f",
"build_date" : "2018-09-10T20:12:43.732Z",
"build_snapshot" : false,
"lucene_version" : "6.6.1"
},
"tagline" : "You Know, for Search"
}
[root@localhost ~]#
ikbana如何连接docker
可视化Install Portainer with Docker on Linux - Portainer Documentation 文档
#安装 docker run -d -p 8088:9000 --restart=always -v /var/run/docker.sock:/var/run/docker.sock --privileged=true portainer/portainer
http://192.168.0.16:8088/#/init/admin
是一种轻量级、可执行的独立软件包，用来打包软件运行环境和基于运行环境开发的软件，它包台运行某个软件所需的所有内容，包括代码、运行时、库、环变量和配置文件
所有的应用，直接打包docker镜像，就可以直接跑起来！
如何获得镜像
- 从远程仓库下载
- 朋友拷贝
- 自己制作一个镜像dockerfile
UnionFS（联合文件系统〕
UnionFS（联合文件系统）：Union文件系统（UnionFS)是一种分层、轻量级并且高性能的文件系统，它支持对文件系统的修改作为一次提交来一层层的叠加，同时可以将不同目录挂载到同一个拟文件系统下（unite several directories into a single virtual filesystem)。Union文件系统是Docker镜像的基础。镜像可以通过分层来讲行继承，基于基础镜像（没有父像），可以制作各种具体的应用镜像。
特性：一次同时加载多个文件系统，但从外面看起来，只能看到一文件系统，联合加载会巴各层文件系统叠加起来，这样最终的文件系统会包含所有底层的文件和目录
Docker镜像加载原理
docker的镜像实际上由一层一层的文件系统组成，这种层级的文件系统UnionFS。
bootfs(bootfilesystem)主要包含bootloader和kernel,bootloaderæ要是引导Linux刚启动时会加载bootfs文件系
统，在Docker镜像的最底层是bootfso这一层与我们典型的Linux/Unix系统是一样的，包含boot加载器和内核。当boot加载完成之后整个内核就都在内存中了，此时内存的使用权已由bootfs转交给内核，此时系统也会卸载bootfs。
rootfs(rootfilesystem)，在bootfs之上。包含的就是典型Linux系统中的/dev,/proc,/bin,/etc等标准目录和文件。rootfs就是各种不同的操作系统发行版，比如Ubuntu，centos等等。
[root@localhost ~]# docker pull redis Using default tag: latest latest: Pulling from library/redis a2abf6c4d29d: Already exists c7a4e4382001: Pull complete 4044b9ba67c9: Pull complete c8388a79482f: Pull complete 413c8bb60be2: Pull complete 1abfd3011519: Pull complete Digest: sha256:db485f2e245b5b3329fdc7eff4eb00f913e09d8feb9ca720788059fdc2ed8339 Status: Downloaded newer image for redis:latest docker.io/library/redis:latest [root@localhost ~]#
思考：为什么Docker镜像要采用这种分层的结构呢？
最大的好处，我觉得莫过于是资源共享了！比如有多个境像都从相同的Base源像构建而来，宿主机只需在磁盘上保留一份base像，同时内存中也只需要载一份b醑e像，这样就可以为所有的容器服务了，而目漳像的每一层都可以被共享。点看镜像分层的方式可以通过docker image inspect命令！
[root@localhost ~]# docker inspect redis:latest
[
{
"Id": "sha256:7614ae9453d1d87e740a2056257a6de7135c84037c367e1fffa92ae922784631",
"RepoTags": [
"redis:latest"
],
"RepoDigests": [
"redis@sha256:db485f2e245b5b3329fdc7eff4eb00f913e09d8feb9ca720788059fdc2ed8339"
],
"Parent": "",
"Comment": "",
"Created": "2021-12-21T12:42:49.755107412Z",
"Container": "13d25f53410417c5220c8dfe8bd49f06abdbcd69faa62a9b877de02464bb04a3",
"ContainerConfig": {
"Hostname": "13d25f534104",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"6379/tcp": {}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"GOSU_VERSION=1.12",
"REDIS_VERSION=6.2.6",
"REDIS_DOWNLOAD_URL=http://download.redis.io/releases/redis-6.2.6.tar.gz",
"REDIS_DOWNLOAD_SHA=5b2b8b7a50111ef395bf1c1d5be11e6e167ac018125055daa8b5c2317ae131ab"
],
"Cmd": [
"/bin/sh",
"-c",
"#(nop) ",
"CMD ["redis-server"]"
],
"Image": "sha256:e093f59d716c95cfce82c676f099b960cc700432ab531388fcedf79932fc81ec",
"Volumes": {
"/data": {}
},
"WorkingDir": "/data",
"Entrypoint": [
"docker-entrypoint.sh"
],
"OnBuild": null,
"Labels": {}
},
"DockerVersion": "20.10.7",
"Author": "",
"Config": {
"Hostname": "",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"6379/tcp": {}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"GOSU_VERSION=1.12",
"REDIS_VERSION=6.2.6",
"REDIS_DOWNLOAD_URL=http://download.redis.io/releases/redis-6.2.6.tar.gz",
"REDIS_DOWNLOAD_SHA=5b2b8b7a50111ef395bf1c1d5be11e6e167ac018125055daa8b5c2317ae131ab"
],
"Cmd": [
"redis-server"
],
"Image": "sha256:e093f59d716c95cfce82c676f099b960cc700432ab531388fcedf79932fc81ec",
"Volumes": {
"/data": {}
},
"WorkingDir": "/data",
"Entrypoint": [
"docker-entrypoint.sh"
],
"OnBuild": null,
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 112691373,
"VirtualSize": 112691373,
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/b94e3e76fe43e5b189d59382a1ca370bec538d1a0dea10e3b031a4bf9c4c57c1/diff:/var/lib/docker/overlay2/351c8e053f1467ef695036aefc82871a6bf3a9dc0c97b480aab6fdd06750f6ed/diff:/var/lib/docker/overlay2/ffe7db0d850a2c19799407fa06000e48e3856775840c21d427fbbc1688b8a4e7/diff:/var/lib/docker/overlay2/1aaf52a048a5b7731782f464e980d83ec1caa9010fc5289e572edab5ea00365b/diff:/var/lib/docker/overlay2/3a015bf48294c76365caf543e0470eede7d47c151551af6714519d2b282bb976/diff",
"MergedDir": "/var/lib/docker/overlay2/8e7f70fc7b48c75a391cd5887f4dbd61584ca25f8184de36a6385f0b1d96f1a9/merged",
"UpperDir": "/var/lib/docker/overlay2/8e7f70fc7b48c75a391cd5887f4dbd61584ca25f8184de36a6385f0b1d96f1a9/diff",
"WorkDir": "/var/lib/docker/overlay2/8e7f70fc7b48c75a391cd5887f4dbd61584ca25f8184de36a6385f0b1d96f1a9/work"
},
"Name": "overlay2"
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:2edcec3590a4ec7f40cf0743c15d78fb39d8326bc029073b41ef9727da6c851f",
"sha256:9b24afeb7c2f21e50a686ead025823cd2c6e9730c013ca77ad5f115c079b57cb",
"sha256:4b8e2801e0f956a4220c32e2c8b0a590e6f9bd2420ec65453685246b82766ea1",
"sha256:529cdb636f61e95ab91a62a51526a84fd7314d6aab0d414040796150b4522372",
"sha256:9975392591f2777d6bf4d9919ad1b2c9afa12f9a9b4d260f45025ec3cc9b18ed",
"sha256:8e5669d8329116b8444b9bbb1663dda568ede12d3dbcce950199b582f6e94952"
]
},
"Metadata": {
"LastTagTime": "0001-01-01T00:00:00Z"
}
}
]
[root@localhost ~]#
特点
docker 镜像都是只读，当容器启动后，一个新的可写层被加载到镜像的顶部！
这一层就是我们通常说的容器层，容器层之下都叫镜像层。
如何提交一个自己的镜像？Commit 镜像**
docker commit #提交容器成为一个副本 #命令和git原理类似 docker cimmit -m="提交描述信息" -a="作者" 容器ID 目标镜像名：[TAG]
练习
#启动一个默认的tomcat #默认的webapps 没有文件 #拷贝文件 #将修改后的容器通过commit 提交为一个镜像
[root@localhost ~]# docker commit -a="lxf" -m="add web app" 5b07255721fa tomcat02:1.0 sha256:aff84909b34e9948fa6c0ef61871d0e200a1b465176b82151953ca78376086ff [root@localhost ~]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE tomcat02 1.0 aff84909b34e 11 seconds ago 684MB nginx latest 605c77e624dd 3 months ago 141MB tomcat 9.0 b8e65a4d736d 3 months ago 680MB tomcat latest fb5657adc892 3 months ago 680MB redis latest 7614ae9453d1 3 months ago 113MB mysql 5.7 c20987f18b13 3 months ago 448MB centos latest 5d0da3dc9764 6 months ago 231MB portainer/portainer latest 580c0e4e98b0 12 months ago 79.1MB elasticsearch latest 5acf0e8da90b 3 years ago 486MB [root@localhost ~]# docker commit -a="lxf" -m="add web app" 5b07255721fa tomcat02:1.0
