万字详解Docker架构原理功能及使用
Posted 数据和云
tags:
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一、简介
1、了解Docker的前生LXC
LXC为Linux Container的简写。可以提供轻量级的虚拟化，以便隔离进程和资源，而且不需要提供指令解释机制以及全虚拟化的其他复杂性。相当于C++中的NameSpace。容器有效地将由单个操作系统管理的资源划分到孤立的组中，以更好地在孤立的组之间平衡有冲突的资源使用需求。
总结：Linux Container是一种轻量级的虚拟化的手段。
2、LXC与docker什么关系？
3、什么是docker
4、docker官方文档
5、为什么docker越来越受欢迎
容器化越来越受欢迎，因为容器是：
灵活：即使是最复杂的应用也可以集装箱化。
轻量级：容器利用并共享主机内核。
可互换：您可以即时部署更新和升级。
便携式：您可以在本地构建，部署到云，并在任何地方运行。
可扩展：您可以增加并自动分发容器副本。
可堆叠：您可以垂直和即时堆叠服务。
镜像和容器（contalners）
容器和虚拟机
6、docker版本
7、docker和openstack的几项对比
8、容器在内核中支持2种重要技术
cgroup的api以一个伪文件系统的实现方式，用户的程序可以通过文件系统实现cgroup的组件管理
cgroup的组件管理操作单元可以细粒度到线程级别，另外用户可以创建和销毁cgroup，从而实现资源载分配和再利用
所有资源管理的功能都以子系统的方式实现，接口统一子任务创建之初与其父任务处于同一个cgroup的控制组
资源限制：可以对任务使用的资源总额进行限制
优先级分配：通过分配的cpu时间片数量以及磁盘IO带宽大小，实际上相当于控制了任务运行优先级
资源统计：可以统计系统的资源使用量，如cpu时长，内存用量等
任务控制：cgroup可以对任务执行挂起、恢复等操作
9、了解docker三个重要概念
10、docker的主要用途
发布服务不用担心服务器的运行环境，所有的服务器都是自动分配docker，自动部署，自动安装，自动运行
再不用担心其他服务引擎的磁盘问题，cpu问题，系统问题了
资源利用更出色
自动迁移，可以制作镜像，迁移使用自定义的镜像即可迁移，不会出现什么问题
管理更加方便了
11、docker改变了什么
面向产品：产品交付
面向开发：简化环境配置
面向测试：多版本测试
面向运维：环境一致性
面向架构：自动化扩容（微服务）
二、docker架构
1、总体架构
distribution 负责与docker registry交互，上传洗澡镜像以及v2 registry 有关的源数据
registry负责docker registry有关的身份认证、镜像查找、镜像验证以及管理registry mirror等交互操作
image 负责与镜像源数据有关的存储、查找，镜像层的索引、查找以及镜像tar包有关的导入、导出操作
reference负责存储本地所有镜像的repository和tag名，并维护与镜像id之间的映射关系
layer模块负责与镜像层和容器层源数据有关的增删改查，并负责将镜像层的增删改查映射到实际存储镜像层文件的graphdriver模块
graghdriver是所有与容器镜像相关操作的执行者
2、docker架构2
3、docker架构3
三、docker架构2各个模块的功能（带完善）
1、docker client
2、docker daemon
3、docker server
4、engine
5、job
6、docker registry
7、Graph
9、libcontainer
10、docker container
用户通过指定容器镜像，使得Docker容器可以自定义rootfs等文件系统；
用户通过指定计算资源的配额，使得Docker容器使用指定的计算资源；
用户通过配置网络及其安全策略，使得Docker容器拥有独立且安全的网络环境；
用户通过指定运行的命令，使得Docker容器执行指定的工作。
四、docker简单使用
1、安装
yum install docker -y
systemctl enable docker
systemctl start dockervim /usr/lib/systemd/system/docker.service[root@web1 ~]# vim /usr/lib/systemd/system/docker.service
[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.com
After=network.target
Wants=docker-storage-setup.service
Requires=docker-cleanup.timer
[Service]
Type=notify
NotifyAccess=main
EnvironmentFile=-/run/containers/registries.conf
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
Environment=GOTRACEBACK=crash
Environment=DOCKER_HTTP_HOST_COMPAT=1
Environment=PATH=/usr/libexec/docker:/usr/bin:/usr/sbin
ExecStart=/usr/bin/dockerd-current --registry-mirror=https://rfcod7oz.mirror.aliyuncs.com #这个值可以登陆阿里云账号请参考下图
--add-runtime docker-runc=/usr/libexec/docker/docker-runc-current
--default-runtime=docker-runc
--exec-opt native.cgroupdriver=systemd
--userland-proxy-path=/usr/libexec/docker/docker-proxy-current
--init-path=/usr/libexec/docker/docker-init-current
--seccomp-profile=/etc/docker/seccomp.json
$OPTIONS
$DOCKER_STORAGE_OPTIONS
$DOCKER_NETWORK_OPTIONS
$ADD_REGISTRY
$BLOCK_REGISTRY
$INSECURE_REGISTRY
$REGISTRIES
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity
TimeoutStartSec=0
Restart=on-abnormal
KillMode=process
[Install]
WantedBy=multi-user.target
[root@web1 ~]# docker version
Client:
Version: 1.13.1
API version: 1.26
Package version: docker-1.13.1-96.gitb2f74b2.el7.centos.x86_64
Go version: go1.10.3
Git commit: b2f74b2/1.13.1
Built: Wed May 1 14:55:20 2019
OS/Arch: linux/amd64
Server:
Version: 1.13.1
API version: 1.26 (minimum version 1.12)
Package version: docker-1.13.1-96.gitb2f74b2.el7.centos.x86_64
Go version: go1.10.3
Git commit: b2f74b2/1.13.1
Built: Wed May 1 14:55:20 2019
OS/Arch: linux/amd64
Experimental: falsedocker pull alpine #下载镜像
docker search nginx #查看镜像
docker pull nginx4、查看已经下载的镜像
[root@web1 ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
zxg/my_nginx v1 b164f4c07c64 8 days ago 126 MB
zxg/my_nginx latest f07837869dfc 8 days ago 126 MB
docker.io/nginx latest e445ab08b2be 2 weeks ago 126 MB
docker.io/alpine latest b7b28af77ffe 3 weeks ago 5.58 MB
docker.io/centos latest 9f38484d220f 4 months ago 202 MB
5、导出镜像
docker save nginx >/tmp/nginx.tar.gz
6、删除镜像
docker rmi -f nginx
7、导入镜像
docker load </tmp/nginx.tar.gz
8、默认配置文件
[Unit]Description=Docker Application Container EngineDocumentation=http://docs.docker.comAfter=network.targetWants=docker-storage-setup.serviceRequires=docker-cleanup.timer[Service]Type=notifyNotifyAccess=mainEnvironmentFile=-/run/containers/registries.confEnvironmentFile=-/etc/sysconfig/dockerEnvironmentFile=-/etc/sysconfig/docker-storageEnvironmentFile=-/etc/sysconfig/docker-networkEnvironment=GOTRACEBACK=crashEnvironment=DOCKER_HTTP_HOST_COMPAT=1Environment=PATH=/usr/libexec/docker:/usr/bin:/usr/sbinExecStart=/usr/bin/dockerd-current --registry-mirror=https://rfcod7oz.mirror.aliyuncs.com--add-runtime docker-runc=/usr/libexec/docker/docker-runc-current--default-runtime=docker-runc--exec-opt native.cgroupdriver=systemd--userland-proxy-path=/usr/libexec/docker/docker-proxy-current--init-path=/usr/libexec/docker/docker-init-current--seccomp-profile=/etc/docker/seccomp.json$OPTIONS$DOCKER_STORAGE_OPTIONS$DOCKER_NETWORK_OPTIONS$ADD_REGISTRY$BLOCK_REGISTRY$INSECURE_REGISTRY$REGISTRIESExecReload=/bin/kill -s HUP $MAINPIDLimitNOFILE=1048576LimitNPROC=1048576LimitCORE=infinityTimeoutStartSec=0Restart=on-abnormalKillMode=process[Install]WantedBy=multi-user.target
--graph=/opt/docker
--dns=xxxx的方式指定
9、运行hello world
[root@web1 overlay2]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEzxg/my_nginx v1 b164f4c07c64 8 days ago 126 MBzxg/my_nginx latest f07837869dfc 8 days ago 126 MBdocker.io/nginx latest e445ab08b2be 2 weeks ago 126 MBdocker.io/alpine latest b7b28af77ffe 3 weeks ago 5.58 MBdocker.io/centos latest 9f38484d220f 4 months ago 02 MB[root@web1 overlay2]# docker run centos echo "hello world"hello world
10、运行一个容器-run
[root@web1 overlay2]# docker run -it alpine sh #运行并进入alpine/ # lsbin etc lib mnt proc run srv tmp vardev home media opt root sbin sys usr/ # cd tmp/tmp # exit
[root@web1 overlay2]# docker run -it -d --name test1 alpineac46c019b800d34c37d4f9dcd56c974cb82eca3acf185e5f8f80c8a60075e343[root@web1 overlay2]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESac46c019b800 alpine "/bin/sh" 5 seconds ago Up 3 seconds test1
[root@web1 overlay2]# docker run -it --rm --name centos nginx^C[root@web1 overlay2]###另开一个窗口[root@web1 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES3397b96ea7bd nginx "nginx -g 'daemon ..." 27 seconds ago Up 25 seconds 80/tcp centosac46c019b800 alpine "/bin/sh" 4 minutes ago Up 4 minutes test1[root@web1 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESac46c019b800 alpine "/bin/sh" 4 minutes ago Up 4 minutes test1
11、如何进入容器
[root@web1 overlay2]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES9fc796e928d7 nginx "sh" 2 minutes ago Up 8 seconds 80/tcp mynginxac46c019b800 alpine "/bin/sh" 12 minutes ago Up 12 minutes test1[root@web1 overlay2]# docker attach mynginx## lsbin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var# exit[root@web1 overlay2]# docker attach mynginxYou cannot attach to a stopped container, start it first[root@web1 overlay2]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESac46c019b800 alpine "/bin/sh" 13 minutes ago Up 13 minutes test1[root@web1 overlay2]#
[root@web1 overlay2]# docker exec -it mynginx sh# lsbin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var# exit[root@web1 overlay2]# docker padocker: 'pa' is not a docker command.See 'docker --help'[root@web1 overlay2]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES6fc2d091cfe9 nginx "nginx -g 'daemon ..." 45 seconds ago Up 43 seconds 80/tcp mynginxac46c019b800 alpine "/bin/sh" 16 minutes ago Up 16 minutes test1
12、查看docker进程及删除容器
[root@web1 overlay2]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES9fc796e928d7 nginx "sh" 2 minutes ago Up 8 seconds 80/tcp mynginxac46c019b800 alpine "/bin/sh" 12 minutes ago Up 12 minutes test1
[root@web1 overlay2]# docker ps -a #-a :显示所有的容器，包括未运行的CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES9fc796e928d7 nginx "sh" 4 minutes ago Exited (0) About a minute ago mynginxac46c019b800 alpine "/bin/sh" 15 minutes ago Up 15 minutes test13bf234febeaa alpine "sh" 17 minutes ago Exited (0) 16 minutes ago youthful_lumiereab113c63f0b4 centos "echo 'hello world'" 31 minutes ago Exited (0) 31 minutes ago infallible_torvaldsb326027dcf42 zxg/my_nginx "nginx" 8 days ago Exited (0) 8 days ago my_nginx4f1f1ca319f2 centos "bash" 8 days ago Exited (137) 8 days ago musing_lichterman64b4e32991c7 nginx "nginx -g 'daemon ..." 12 days ago Exited (0) 12 days ago mynginx1aee506fe7b5a alpine "sh" 12 days ago Created infallible_haibt70620c73b9a0 alpine "sh" 12 days ago Created gallant_volhard7655cbf87bb0 alpine "sh" 12 days ago Created agitated_brahmagupta33fb949372e8 fce289e99eb9 "/hello" 12 days ago Created elastic_dijkstra9de47616aea4 fce289e99eb9 "/hello" 13 days ago Created confident_fermi[root@web1 overlay2]# docker rm 9fc796e928d7 #rm时删除一个或多个容器9fc796e928d7
13、查看容器详细信息
[root@web1 overlay2]# docker inspect mynginx
[
{
"Id": "6fc2d091cfe9b0484da3e70db842446bbdfeb7f5e5409c2e40ae21b99498d010",
"Created": "2019-08-07T08:57:48.864538933Z",
"Path": "nginx",
"Args": [
"-g",
"daemon off;"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 119948,
"ExitCode": 0,
"Error": "",
"StartedAt": "2019-08-07T08:57:49.417992182Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:e445ab08b2be8b178655b714f89e5db9504f67defd5c7408a00bade679a50d44",
"ResolvConfPath": "/var/lib/docker/containers/6fc2d091cfe9b0484da3e70db842446bbdfeb7f5e5409c2e40ae21b99498d010/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/6fc2d091cfe9b0484da3e70db842446bbdfeb7f5e5409c2e40ae21b99498d010/hostname",
"HostsPath": "/var/lib/docker/containers/6fc2d091cfe9b0484da3e70db842446bbdfeb7f5e5409c2e40ae21b99498d010/hosts",
"LogPath": "",
"Name": "/mynginx",
"RestartCount": 0,
"Driver": "overlay2",
"MountLabel": "",
"ProcessLabel": "",
"AppArmorProfile": "",
"ExecIDs": null,
"HostConfig": {
"Binds": null,
"ContainerIDFile": "",
"LogConfig": {
"Type": "journald",
"Config": {}
},
"NetworkMode": "default",
"PortBindings": {},
"RestartPolicy": {
"Name": "no",
"MaximumRetryCount": 0
},
"AutoRemove": false,
"VolumeDriver": "",
"VolumesFrom": null,
"CapAdd": null,
"CapDrop": null,
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "",
"Cgroup": "",
"Links": null,
"OomScoreAdj": 0,
"PidMode": "",
"Privileged": false,
"PublishAllPorts": false,
"ReadonlyRootfs": false,
"SecurityOpt": null,
"UTSMode": "",
"UsernsMode": "",
"ShmSize": 67108864,
"Runtime": "docker-runc",
"ConsoleSize": [
0,
0
],
"Isolation": "",
"CpuShares": 0,
"Memory": 0,
"NanoCpus": 0,
"CgroupParent": "",
"BlkioWeight": 0,
"BlkioWeightDevice": null,
"BlkioDeviceReadBps": null,
"BlkioDeviceWriteBps": null,
"BlkioDeviceReadIOps": null,
"BlkioDeviceWriteIOps": null,
"CpuPeriod": 0,
"CpuQuota": 0,
"CpuRealtimePeriod": 0,
"CpuRealtimeRuntime": 0,
"CpusetCpus": "",
"CpusetMems": "",
"Devices": [],
"DiskQuota": 0,
"KernelMemory": 0,
"MemoryReservation": 0,
"MemorySwap": 0,
"MemorySwappiness": -1,
"OomKillDisable": false,
"PidsLimit": 0,
"Ulimits": null,
"CpuCount": 0,
"CpuPercent": 0,
"IOMaximumIOps": 0,
"IOMaximumBandwidth": 0
},
"GraphDriver": {
"Name": "overlay2",
"Data": {
"LowerDir": "/var/lib/docker/overlay2/937140af0aee6c43f04c2d7b72e6b5451a44fef921417e8236d9fe01e9286c7a-init/diff:/var/lib/docker/overlay2/d8e95505fc3894eb30b48e4b0f48ab5e89d99c09a07c79c0b057c611621e31eb/diff:/var/lib/docker/overlay2/b2a6a25974bf17398b698a27208711574be3c69a2cd06658bbe838359f373a27/diff:/var/lib/docker/overlay2/d4610bc89b3ba8ad6ab30ea895fc3a06efff15db493d86ac9bc100e04abbab67/diff",
"MergedDir": "/var/lib/docker/overlay2/937140af0aee6c43f04c2d7b72e6b5451a44fef921417e8236d9fe01e9286c7a/merged",
"UpperDir": "/var/lib/docker/overlay2/937140af0aee6c43f04c2d7b72e6b5451a44fef921417e8236d9fe01e9286c7a/diff",
"WorkDir": "/var/lib/docker/overlay2/937140af0aee6c43f04c2d7b72e6b5451a44fef921417e8236d9fe01e9286c7a/work"
}
},
"Mounts": [],
"Config": {
"Hostname": "6fc2d091cfe9",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"80/tcp": {}
},
"Tty": true,
"OpenStdin": true,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"NGINX_VERSION=1.17.2",
"NJS_VERSION=0.3.3",
"PKG_RELEASE=1~buster"
],
"Cmd": [
"nginx",
"-g",
"daemon off;"
],
"ArgsEscaped": true,
"Image": "nginx",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {
"maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
},
"StopSignal": "SIGTERM"
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "3ece36008fbc5f3f46d3d251cf803c1478cc14032d74a36747e4ed8a115b81df",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {
"80/tcp": null
},
"SandboxKey": "/var/run/docker/netns/3ece36008fbc",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "898de81d97d54d2b60aeb6cc77ef1b4f9b481d1b72f542faa496494594024eac",
"Gateway": "172.17.0.1",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "172.17.0.3", #看到ip地址
"IPPrefixLen": 16,
"IPv6Gateway": "",
"MacAddress": "02:42:ac:11:00:03",
"Networks": {
"bridge": {
"IPAMConfig": null,
"Links": null,
"Aliases": null,
"NetworkID": "2edae9131e77500a56d251b94ab2cdf0bc86f8df9f2453fa46bf4bab2f7be99f",
"EndpointID": "898de81d97d54d2b60aeb6cc77ef1b4f9b481d1b72f542faa496494594024eac",
"Gateway": "172.17.0.1",
"IPAddress": "172.17.0.3",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "02:42:ac:11:00:03"
}
}
}
}
]
[root@web1 overlay2]# curl 172.17.0.1 #访问一下
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Test Page for the Nginx HTTP Server on Fedora</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<style type="text/css">
/*<![CDATA[*/
body {
background-color: #fff;
color: #000;
font-size: 0.9em;
font-family: sans-serif,helvetica;
margin: 0;
padding: 0;
}
:link {
color: #c00;
}
:visited {
color: #c00;
}
a:hover {
color: #f50;
}
h1 {
text-align: center;
margin: 0;
padding: 0.6em 2em 0.4em;
background-color: #294172;
color: #fff;
font-weight: normal;
font-size: 1.75em;
border-bottom: 2px solid #000;
}
h1 strong {
font-weight: bold;
font-size: 1.5em;
}
h2 {
text-align: center;
background-color: #3C6EB4;
font-size: 1.1em;
font-weight: bold;
color: #fff;
margin: 0;
padding: 0.5em;
border-bottom: 2px solid #294172;
}
hr {
display: none;
}
.content {
padding: 1em 5em;
}
.alert {
border: 2px solid #000;
}
img {
border: 2px solid #fff;
padding: 2px;
margin: 2px;
}
a:hover img {
border: 2px solid #294172;
}
.logos {
margin: 1em;
text-align: center;
}
/*]]>*/
</style>
</head>
<body>
<h1>Welcome to <strong>nginx</strong> on Fedora!</h1>
<div class="content">
<p>This page is used to test the proper operation of the
<strong>nginx</strong> HTTP server after it has been
installed. If you can read this page, it means that the
web server installed at this site is working
properly.</p>
<div class="alert">
<h2>Website Administrator</h2>
<div class="content">
<p>This is the default <tt>index.html</tt> page that
is distributed with <strong>nginx</strong> on
Fedora. It is located in
<tt>/usr/share/nginx/html</tt>.</p>
<p>You should now put your content in a location of
your choice and edit the <tt>root</tt> configuration
directive in the <strong>nginx</strong>
configuration file
<tt>/etc/nginx/nginx.conf</tt>.</p>
</div>
</div>
<div class="logos">
<a href="http://nginx.net/"><img
src="nginx-logo.png"
alt="[ Powered by nginx ]"
width="121" height="32" /></a>
<a href="http://fedoraproject.org/"><img
src="poweredby.png"
alt="[ Powered by Fedora ]"
width="88" height="31" /></a>
</div>
</div>
</body>
</html>
14、查看日志
[root@web1 ~]# docker logs -f mynginx
出处：https://www.cnblogs.com/zhangxingeng/p/11236968.html
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