Docker《一：简介和安装》简介：Docker 是一个开源的应用容器引擎，让开发者可以打包他们的应用以及依赖包到一个可

简介：Docker 是一个开源的应用容器引擎，让开发者可以打包他们的应用以及依赖包到一个可移植的镜像中，然后发布到任何流行的 Linux或Windows 机器上，也可以实现虚拟化。容器是完全使用沙箱机制，相互之间不会有任何接口

发展历程：实体机---》虚拟机---》容器

虚拟机和容器的对比：当我们在物理服务器创建一台虚拟机时，便需要虚拟出一套硬件并在上面运行完整的操作系统，每台虚拟机都占用许多的服务器资源。虚拟机的不足之外来自于对物理服务器资源的消耗，当然docker也不是没有缺点，比如必须使用root账号，这可能会带来一些安全问题

背景：最容易想到的就是实际开发过程中，很容易出现开发测试以及生产环境不一致情况，比如最经典的就是“明明在我本地是问题的”，使用docker就可以完美的杜绝这种现象。

一：docker安装

特别注意的是docker官方对Linux不同版本有不同的要求，比如我现在的系统版本是官方要求是查看自己虚拟机版本

cat /etc/redhat-release

1.1# 卸载旧版本的Docker

sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

1.2安装`yum-utils`包

sudo yum install -y yum-utils

1.3设置仓库地址

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

注意：download.docker.com/linux/cento… 地址是国外的，为了方便我们下载镜像更快，这里我们不用官方提供的仓库地址，我们可以使用国内的仓库地址比如使用阿里云镜像地址

sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

1.4安装 Docker 引擎

sudo yum install docker-ce docker-ce-cli containerd.io

注：默认是安装最新的，也可以选择指定版本，

yum list docker-ce --showduplicates | sort -r

然后进行安装

sudo yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io

1.5启动docker

sudo systemctl start docker

1.6Docker镜像加速

使用加速器可以进一步提升获取docker官方镜像的速度登陆阿里云获取个人镜像加速地址找到镜像加速器地址配置镜像加速器步骤

sudo mkdir -p /etc/docker

配置daemon.json内容

sudo tee /etc/docker/daemon.json <<-'EOF' { "registry-mirrors": ["你的镜像加速器地址"] } EOF

重新加载daemon和重启docker

sudo systemctl daemon-reload 
sudo systemctl restart docker

1.7停止docker

sudo systemctl stop docker

1.8重启docker

sudo systemctl restart docker

1.9设置docker开机自启

查看所有设置开机启动服务

systemctl list-unit-files | grep enable

设置docker开机启动

systemctl enable docker.service

1.10卸载docker

卸载Docker包

sudo yum remove docker-ce

镜像、容器、自定义配置文件等并不会随着Docker的卸载自动删除，需要执行一下命令手动删除：

sudo rm -rf /var/lib/docker

二：Docker中的镜像和容器

2.1镜像

镜像可以看成是由多个镜像层叠加起来的一个文件系统（通过UnionFS与AUFS文件联合系统实现），镜像层也可以简单理解为一个基本的镜像，而每个镜像层之间通过指针的形式进行叠加。镜像层的主要组成部分包括镜像层 ID、镜像层指针「指向父层」、元数据「 Layer Metadata，包含了 Docker 构建和运行的信息和父层的层次信息」。只读层和读写层「Top Layer」的组成部分基本一致，同时读写层可以转换成只读层「通过docker commit 操作实现」

2.1.1关于镜像常用命令

查看本地镜像

docker images

docker images -q
# 只展示image id

搜索镜像

docker search mysql

从仓库下载镜像

docker pull mysql

如果不指定版本，默认下载最新版本镜像，下载指定版本镜像关于镜像版本可以从dockhub官网上获取，比如

docker pull mysql:5.7.35

删除镜像 删除指定id镜像

docker rmi imagesId

删除所有镜像

 docker rmi -f $(docker images -aq)

2.2容器

容器（container）的定义和镜像（image）几乎一模一样，也是一堆层的统一视角，唯一区别在于容器的最上面那一层是可读可写的。要点：容器 = 镜像 + 读写层，并且容器的定义并没有提及是否要运行容器。

2.2.1关于容器常用命令

查看当前正在运行的容器

 docker ps

查看当前以及历史上运行过的容器

docker ps -a

创建容器

docker run [可选参数] iamge
#可选参数说明
--name="Name" 容器名字，用来区分容器
-d             容器以后台方式运行
-v             目录挂载
-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 3306：3306
       -p ip：主机端口：容器端口
	   -p 主机端口：容器端口（最常用）
	   -p 容器端口
-P     随机指定端口

示例：我们创建一个mysql容器

sudo docker run -p 3306:3306 --name mysql \
-v /mydata/mysql/log:/var/log/mysql \
-v /mydata/mysql/data:/var/lib/mysql \
-v /mydata/mysql/conf:/etc/mysql \
-e MYSQL_ROOT_PASSWORD=root \
-d mysql:5.7

进入容器 第一种方式

docker exec -it mysql /bin/bash

第二种方式

docker attach 容器id

docker exec #进入当前容器后开启一个新的终端，可以在里面操作。（常用）
docker attach # 进入容器正在执行的终端
退出容器 直接在容器内部输入exit指令,或者使用快捷键 ctrl+d
启动容器

docker start mysql

停止容器

docker stop mysql

重启容器

docker restart mysql

删除容器
查看容器的元数据

docker inspect 1f8fa87898b3

[
    {
        "Id": "1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df",
        "Created": "2021-09-13T01:30:43.616983125Z",
        "Path": "docker-entrypoint.sh",
        "Args": [
            "mysqld"
        ],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 3048,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2021-09-13T01:30:45.912679674Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:1d7aba9171693947d53f474014821972bf25d72b7d143ce4af4c8d8484623417",
        "ResolvConfPath": "/var/lib/docker/containers/1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df/hostname",
        "HostsPath": "/var/lib/docker/containers/1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df/hosts",
        "LogPath": "/var/lib/docker/containers/1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df/1f8fa87898b3e572b296f0ca8419ce9db3b145c5c78760ae0fd332c14458c5df-json.log",
        "Name": "/mysql",
        "RestartCount": 0,
        "Driver": "overlay2",
        "Platform": "linux",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "/mydata/mysql/log:/var/log/mysql",
                "/mydata/mysql/data:/var/lib/mysql",
                "/mydata/mysql/conf:/etc/mysql"
            ],
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "default",
            "PortBindings": {
                "3306/tcp": [
                    {
                        "HostIp": "",
                        "HostPort": "3306"
                    }
                ]
            },
            "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/overlay2/9579a80af707e228b83c36c35bf78d16e60c393c53db6b1b08af2614571fb751-init/diff:/var/lib/docker/overlay2/46bdd25b268e86c78340efc55df2b3168a5aa94a866a126e21339681122bf4b9/diff:/var/lib/docker/overlay2/fe293b3d8a420345489e9479d65f4b66339540fc1b94c00de09229be6f056482/diff:/var/lib/docker/overlay2/1356923f598837d4df98372e0d208fe804bf30ce2f3a5177fd258716f420be1e/diff:/var/lib/docker/overlay2/f90dcd25409626ed17b0cf1bdc1a11101bce6efaaeb86a019241e42acc823a8b/diff:/var/lib/docker/overlay2/97e80f2b28a293eb012df21495e4d0c44aa5368df371cdfa8f5fae72ff097706/diff:/var/lib/docker/overlay2/7cabee401fcbbbba722980ac36ec12da7169a7bc36e634374e0fffdb197f37be/diff:/var/lib/docker/overlay2/69ae699bc51e647d84772c712bf812f1d5b6a5f18194e8a8eb91680db9f01ee1/diff:/var/lib/docker/overlay2/50200055c27b1afbf9b79a8133b1ad083e5b66c2e5b0da1e47dc4b6a23c64b9e/diff:/var/lib/docker/overlay2/61d455616c1b91f4cf32352612243a295d575f899d1a7eb3470639c96e4f4973/diff:/var/lib/docker/overlay2/56e975d01fa2d44db6bd5e06c96945c451e9404f62384d0b0d492d6c45bda227/diff:/var/lib/docker/overlay2/a710415355de88d8c9bd7b30ec2b82cf3c1a8efcf37eb9ebf40d35a20d41be3c/diff",
                "MergedDir": "/var/lib/docker/overlay2/9579a80af707e228b83c36c35bf78d16e60c393c53db6b1b08af2614571fb751/merged",
                "UpperDir": "/var/lib/docker/overlay2/9579a80af707e228b83c36c35bf78d16e60c393c53db6b1b08af2614571fb751/diff",
                "WorkDir": "/var/lib/docker/overlay2/9579a80af707e228b83c36c35bf78d16e60c393c53db6b1b08af2614571fb751/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "bind",
                "Source": "/mydata/mysql/log",
                "Destination": "/var/log/mysql",
                "Mode": "",
                "RW": true,
                "Propagation": "rprivate"
            },
            {
                "Type": "bind",
                "Source": "/mydata/mysql/data",
                "Destination": "/var/lib/mysql",
                "Mode": "",
                "RW": true,
                "Propagation": "rprivate"
            },
            {
                "Type": "bind",
                "Source": "/mydata/mysql/conf",
                "Destination": "/etc/mysql",
                "Mode": "",
                "RW": true,
                "Propagation": "rprivate"
            }
        ],
        "Config": {
            "Hostname": "1f8fa87898b3",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "3306/tcp": {},
                "33060/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "MYSQL_ROOT_PASSWORD=root",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "GOSU_VERSION=1.12",
                "MYSQL_MAJOR=5.7",
                "MYSQL_VERSION=5.7.35-1debian10"
            ],
            "Cmd": [
                "mysqld"
            ],
            "Image": "mysql:5.7",
            "Volumes": {
                "/var/lib/mysql": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "docker-entrypoint.sh"
            ],
            "OnBuild": null,
            "Labels": {}
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "9ac195d15b9b1eacc735b58eb3c668939481cf055c2bad27495622bb557a29d0",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "3306/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "3306"
                    },
                    {
                        "HostIp": "::",
                        "HostPort": "3306"
                    }
                ],
                "33060/tcp": null
            },
            "SandboxKey": "/var/run/docker/netns/9ac195d15b9b",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "f539a4d8674dd70d0c187213426c37ac7f059f06b46ec4e360b0a634f5eff172",
            "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": "76e2f596aa456af2da972fb9f5fef03e4f48a312c6176e7d1d00e5a60f8dc9e4",
                    "EndpointID": "f539a4d8674dd70d0c187213426c37ac7f059f06b46ec4e360b0a634f5eff172",
                    "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
                }
            }
        }
    }
]

2.3从容器内部拷贝文件

docker cp 容器id:容器内路径 主机目的路径

示例：将容器根路径下的test.html

docker cp 1f8fa87898b3:/test.html /root/

2.4查看容器内存，cpu等使用情况

docker stats

docker stats后面也可以指定容器id，查询单个容器的使用情况

Docker《一：简介和安装》