Tue Jul 6

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Docker入门

Docker

Docker概述

Docker为什么会出现？

问题一：

发布一个项目（jar+Redis+MySql+ jkd+ES）项目不能带上环境安装打包

传统：开发jar，运维部署

现在：开发打包部署上线，一套流程做完

解决方法：

Docker模式：

java --- jar（环境）--- 打包项目带上环境（镜像） --- （Docker仓库：商店）--- 下载发布的镜像 --- 直接运行即可

问题二：

多个应用交叉（端口占用）

解决方法：

Docker通过隔离机制，打包装箱，每个箱子都是隔离的

VM和Docker的对比

技术	隔离措施	性能	备注
VM	开启多个虚拟机	内存占用几个G，启动时间几分钟	VM会搭建Guest OS
Docker	本身就是隔离的	小巧，内存占用最小几MB，秒级启动	Docker利用宿主机的内核，更少的抽象层

Docker的作用

应用更快速交付和部署
更便捷的升级和扩缩容
更简单的系统运维
更高效的计算资源利用

Docker安装

镜像（image）

镜像就好比模板，一个模板类，通过镜像可以创建多个容器

容器（container）

Docker利用容器技术，独立运行一个或一组应用，通过镜像来创建

启动，停止，删除

仓库（repository）

仓库就是存放镜像的地方

仓库分为公有仓库和私有仓库

#拉取docker helloworld镜像
# docker pull hello-world
Using default tag: latest
latest: Pulling from library/hello-world
b8dfde127a29: Pull complete 
Digest: sha256:9f6ad537c5132bcce57f7a0a20e317228d382c3cd61edae14650eec68b2b345c
Status: Downloaded newer image for hello-world:latest
docker.io/library/hello-world:latest

#运行docker hello-world
# docker run hello-world
This message shows that your installation appears to be working correctly.
.....

#查看docker镜像
# docker images
REPOSITORY    TAG       IMAGE ID       CREATED        SIZE
hello-world   latest    d1165f221234   3 months ago   13.3kB
alpine/git    latest    a939554ad0d0   4 months ago   25.1MB
zookeeper     3.5.8     222518b8670a   4 months ago   261MB

Docker常用命令

镜像命令

docker images #查看所有镜像，-a全部信息 -q只显示id
docker search mysql #搜索docker hub的所有镜像
docker pull mysql #下载镜像
docker rmi -f	容器id #删除置顶容器
docker rmi -f $(docker images -aq)	#删除所有镜像

容器命令

docker pull centos #拉取镜像

#容器运行
docker run [可选参数] image
#参数说明
--name="Name"		容器名字
-d							后台方式运行
-it							使用交互运行，进入容器查看内容
-p							指定容器端口 -p 8080:8080
	-p 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
-P							随机指定端口

docker run -it centos /bin/bash

#退出并停止容器
exit

#列出所有的容器
docker ps	#-a列出当前正在运行的容器+带出历史运行过的容器；-n显示最近创建的容器；-q值显示容器编号


#删除容器
docker rm 容器id

#删除所有容器
docker rm -f $(docker ps -aq)
docker ps -a -q | xargs docker rm

#启动容器
docker start 容器id

#重启容器
docker restart 容器id

#停止当前正在运行的容器
docker stop 容器id

#强制停止当前容器
docker kill 容器id

其他常用命令

# 后台进程启动镜像
docker run -d 镜像名

# 常见的坑：docker 容器使用后台运行，就必须要有一个前台进程，docker发现没有应用，就会自动停止

# 查看日志
docker log -tf --tail 10 容器id

# 查看容器元数据
docker inspect 容器id

# 查看容器进程信息
docker top 容器id
UID                 PID                 PPID                C                   STIME               TTY                 TIME                CMD
root                2949                2922                0                   07:14               
root                3047                2949                0                   07:15             

# 进入正在运行的容器
docker exec -it 容器id
# 例子
docker exec -it 0da2de9664ea /bin/bash

docker attach 容器id
#例子
docker attach 0da2de9664ea


# 拷贝容器文件到主机文件
docker cp 容器id:容器内路径 目的主机路径

命令汇总

Docker练习

部署Nginx

# 拉取nginx镜像
docker pull nginx
# 运行nginx容器，本机8080映射到容器80
docker run -d -p 8080:80 --name nginx01 nginx
# 测试
curl 127.0.0.1:8080
# 结果
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

部署Tomcat

# 拉取tomcat镜像
docker pull tomcat
# 运行容器
docker run -d -p 8081:8080 --name tomcat01 tomcat
# 进入tomecat容器中
docker exec -it tomcat01 /bin/bash
cp -r webapps.dist/* webapps
# 测试
curl 127.0.0.1:8081

部署可视化工具

docker run -d -p 9000:9000 --name portainer --restart=always  -v /var/run/docker.sock:/var/run/docker.sock -v  portainer_data:/data portainer/portainer

Docker镜像

Docker镜像加载原理，通俗易懂

Docker镜像加载原理

在这里插入图片描述

bootfs(boot file system) 主要包含bootloader和kernel, bpotloader 主要是引导加载kernel,当我们加载镜像的时候，会通过bootloader加载kernal，Docker镜像最底层是bootfs，当boot加载完成后整个kernal内核都在内存中了，bootfs也就可以卸载，值得注意的是，bootfs是被所有镜像共用的，许多镜像images都是在base image(rootfs)基础上叠加的
rootfs (root file system)，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。

分层理解

在这里插入图片描述

真正干活的是docker上的容器，不同容器都有一个共同的镜像，这个镜像有不同层级，每个层级都有自己的内容，可以共用，docker根据不同的需求来叠加镜像，从而对外暴露一个整体的镜像，每个容器都是精简版的linux系统，bootfs相当于鲸鱼的背，各容器内核kernal共用

Commit镜像

docker commit -m=提交信息 -a=作者 容器id 目标镜像铭:[TAG]

# 例子
docker commit -m='add webapp' -a='ch' 484c0ce002ba tomcat02:1.0
# 效果
(base) chennianzuisuideMacBook-Air:~ chennianzuisui$ docker images
REPOSITORY            TAG       IMAGE ID       CREATED          SIZE
tomcat02              1.0       0296b33fdceb   13 seconds ago   672MB
tomcat                latest    36ef696ea43d   37 hours ago     667MB
nginx                 latest    4f380adfc10f   11 days ago      133MB
portainer/portainer   latest    580c0e4e98b0   3 months ago     79.1MB
hello-world           latest    d1165f221234   4 months ago     13.3kB
alpine/git            latest    a939554ad0d0   4 months ago     25.1MB
zookeeper             3.5.8     222518b8670a   4 months ago     261MB
centos                latest    300e315adb2f   6 months ago     209MB

容器数据卷

使用数据卷

容器之间有一个数据共享的技术，Docker容器中产生的数据，同步到本地

这就是卷技术，即目录的挂载，将我们的容器目录挂载在本机的目录上

卷技术：容器的持久化和同步操作，容器间也可以数据共享

# docker run -it -v 主机目录:容器内目录
# 注意mac下的共享目录需要在dokcer desktop中修改
docker run -it -v /Users/chennianzuisui/ceshi:/home centos /bin/bash
# 查看挂载是否成功,Mounts/Source,Destination
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ docker inspect 23648730c6fe
[
    {
        "Id": "23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469",
        "Created": "2021-07-06T04:43:06.3536085Z",
        "Path": "/bin/bash",
        "Args": [],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 14249,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2021-07-06T04:43:07.4777907Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:300e315adb2f96afe5f0b2780b87f28ae95231fe3bdd1e16b9ba606307728f55",
        "ResolvConfPath": "/var/lib/docker/containers/23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469/hostname",
        "HostsPath": "/var/lib/docker/containers/23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469/hosts",
        "LogPath": "/var/lib/docker/containers/23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469/23648730c6fe45e013da3e82d98e371e78d140fff31a75b4eceea6737adf3469-json.log",
        "Name": "/boring_joliot",
        "RestartCount": 0,
        "Driver": "overlay2",
        "Platform": "linux",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "/Users/chennianzuisui/ceshi:/home"
            ],
            "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/affa313e5e6f9d1903c6e2f1fef5b84b071c346a2b99bbad8981043af0fbc59b-init/diff:/var/lib/docker/overlay2/7e28025e45d3cb2d3ccd44b84416550d52175a599fb76c4843c878843a80c15b/diff",
                "MergedDir": "/var/lib/docker/overlay2/affa313e5e6f9d1903c6e2f1fef5b84b071c346a2b99bbad8981043af0fbc59b/merged",
                "UpperDir": "/var/lib/docker/overlay2/affa313e5e6f9d1903c6e2f1fef5b84b071c346a2b99bbad8981043af0fbc59b/diff",
                "WorkDir": "/var/lib/docker/overlay2/affa313e5e6f9d1903c6e2f1fef5b84b071c346a2b99bbad8981043af0fbc59b/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "bind",
                "Source": "/Users/chennianzuisui/ceshi",
                "Destination": "/home",
                "Mode": "",
                "RW": true,
                "Propagation": "rprivate"
            }
        ],
        "Config": {
            "Hostname": "23648730c6fe",
            "Domainname": "",
            "User": "",
            "AttachStdin": true,
            "AttachStdout": true,
            "AttachStderr": true,
            "Tty": true,
            "OpenStdin": true,
            "StdinOnce": true,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Cmd": [
                "/bin/bash"
            ],
            "Image": "centos",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "org.label-schema.build-date": "20201204",
                "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": "f08d44ef786f0f044872d0e02aedfe4105c058927da39de974d10c19f0a1e298",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {},
            "SandboxKey": "/var/run/docker/netns/f08d44ef786f",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "3d88e3b44cfd67a35073c86ab1feaf03824d4ec0c45a66e89be2345f95c197ce",
            "Gateway": "172.17.0.1",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.5",
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:05",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "4e43df4d3e2df430fd0ccb2faf00eb38df1359ab8a852a4d92299518b308798c",
                    "EndpointID": "3d88e3b44cfd67a35073c86ab1feaf03824d4ec0c45a66e89be2345f95c197ce",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.5",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:05",
                    "DriverOpts": null
                }
            }
        }
    }
]

# centos中操作，mac同步
## centos中操作
cd ./home
touch test.java


## mac中操作
cd /ceshi
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ ls
test.java


# mac操作，centos同步
## mac中操作
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ ls
test.java
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ rm -rf test.java 
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ ls
(base) chennianzuisuideMacBook-Air:ceshi chennianzuisui$ 

## centos中操作
[root@23648730c6fe home]# ls
[root@23648730c6fe home]#