第 3 章 docker-ce 镜像管理 - 李延召的官方网站

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/中。

镜像仓库对应关系：

hub.yunweidashu.com         -->        hub.docker.com
k8sgcr.yunweidashu.com      -->        k8s.gcr.io
registry.yunweidashu.com    -->        registry.k8s.io
ghcr.yunweidashu.com        -->        ghcr.io
gcr.yunweidashu.com         -->        grc.io

搜索镜像：

[root@linux-node1 ~]# docker search nginx

下载镜像

[root@linux-node1 ~]# docker pull nginx

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

配置镜像加速器：https://www.daocloud.io/mirror
curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io

#配置加速器：

[root@linux-node1 ~]# curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io
docker version >= 1.12
{"registry-mirrors": ["http://f1361db2.m.daocloud.io"]}
Success.
You need to restart docker to take effect: sudo systemctl restart docker 
[root@linux-node1 ~]# cat /etc/docker/daemon.json    #查看配置结果
{"registry-mirrors": ["http://f1361db2.m.daocloud.io"]}
[root@linux-node1 ~]# systemctl restart docker.service        #配置完成后重启

[root@linux-node1 ~]# docker pull centos    #下载一个镜像测一下速度

ubuntu

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://uvi4o749.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

Centos

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://uvi4o749.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

windows

1. 安装／升级Docker客户端
对于Windows 10以下的用户，推荐使用Docker Toolbox

Windows安装文件：http://mirrors.aliyun.com/docker-toolbox/windows/docker-toolbox/

对于Windows 10以上的用户 推荐使用Docker for Windows

Windows安装文件：http://mirrors.aliyun.com/docker-toolbox/windows/docker-for-windows/

2. 配置镜像加速器
针对安装了Docker Toolbox的用户，您可以参考以下配置步骤：

创建一台安装有Docker环境的Linux虚拟机，指定机器名称为default，同时配置Docker加速器地址。

docker-machine create --engine-registry-mirror=https://uvi4o749.mirror.aliyuncs.com -d virtualbox default
查看机器的环境配置，并配置到本地，并通过Docker客户端访问Docker服务。

docker-machine env default
eval "$(docker-machine env default)"
docker info
针对安装了Docker for Windows的用户，您可以参考以下配置步骤：

在系统右下角托盘图标内右键菜单选择 Settings，打开配置窗口后左侧导航菜单选择 Docker Daemon。编辑窗口内的JSON串，填写下方加速器地址：

{
  "registry-mirrors": ["https://uvi4o749.mirror.aliyuncs.com"]
}
编辑完成后点击 Apply 保存按钮，等待Docker重启并应用配置的镜像加速器。

注意
Docker for Windows 和 Docker Toolbox互不兼容，如果同时安装两者的话，需要使用hyperv的参数启动。

docker-machine create --engine-registry-mirror=https://uvi4o749.mirror.aliyuncs.com -d hyperv default
Docker for Windows 有两种运行模式，一种运行Windows相关容器，一种运行传统的Linux容器。同一时间只能选择一种模式运行。

1. 安装／升级Docker客户端
对于10.10.3以下的用户 推荐使用Docker Toolbox

Mac安装文件：http://mirrors.aliyun.com/docker-toolbox/mac/docker-toolbox/

对于10.10.3以上的用户 推荐使用Docker for Mac

Mac安装文件：http://mirrors.aliyun.com/docker-toolbox/mac/docker-for-mac/

2. 配置镜像加速器
针对安装了Docker Toolbox的用户，您可以参考以下配置步骤：

创建一台安装有Docker环境的Linux虚拟机，指定机器名称为default，同时配置Docker加速器地址。

docker-machine create --engine-registry-mirror=https://uvi4o749.mirror.aliyuncs.com -d virtualbox default
查看机器的环境配置，并配置到本地，并通过Docker客户端访问Docker服务。

docker-machine env default
eval "$(docker-machine env default)"
docker info
针对安装了Docker for Mac的用户，您可以参考以下配置步骤：

在任务栏点击 Docker Desktop 应用图标 -> Perferences，在左侧导航菜单选择 Docker Engine，在右侧输入栏编辑 json 文件。将

https://uvi4o749.mirror.aliyuncs.com加到"registry-mirrors"的数组里，点击 Apply & Restart按钮，等待Docker重启并应用配置的镜像加速器。

2、镜像与容器联系

Writable Container
Add Apache Image
Add Emacs Image
Debian Base Image
bootfs
kernel

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 将容器保存成一个新镜像

查看本地已有镜像：

[root@linux-node1 ~]# docker images   
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              02256cfb0e4b        31 hours ago        109MB
centos              latest              1e1148e4cc2c        3 weeks ago         202MB
hello-world         latest              4ab4c602aa5e        3 months ago        1.84kB

创建一个容器nginx后台启动:

[root@linux-node1 ~]# docker run -itd nginx

创建一个docker容器默认会从宿主机挂载/resolv.conf /hostname /hosts 这三个文件：

[root@linux-node1 ~]# docker inspect 47cb511b8faf|grep resolv.conf
        "ResolvConfPath": "/var/lib/docker/containers/47cb511b8fafa6c8fceba82198c12c9eaae19dd699995d422d9f55efaed4e704/resolv.conf",
[root@linux-node1 ~]# docker inspect 47cb511b8faf|grep hostname
        "HostnamePath": "/var/lib/docker/containers/47cb511b8fafa6c8fceba82198c12c9eaae19dd699995d422d9f55efaed4e704/hostname",
[root@linux-node1 ~]# docker inspect 47cb511b8faf|grep hosts
        "HostsPath": "/var/lib/docker/containers/47cb511b8fafa6c8fceba82198c12c9eaae19dd699995d422d9f55efaed4e704/hosts",

容器存储对应宿主机的位置：        
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/0b747104a0a8deaef8824f23cc1b57a2d2ad501e8e56d1fbbff0a61645e340c6-init/diff:/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/diff:/var/lib/docker/overlay2/c9d822f8a4c8219b2b34b594f407bf247bde13299e03a05bd7a0fd0f9dde0317/diff:/var/lib/docker/overlay2/e667dae3d4a0983ebabed19877230ee897748c70575849fa2ea5845c0b5edcf2/diff",
                "MergedDir": "/var/lib/docker/overlay2/0b747104a0a8deaef8824f23cc1b57a2d2ad501e8e56d1fbbff0a61645e340c6/merged",
                "UpperDir": "/var/lib/docker/overlay2/0b747104a0a8deaef8824f23cc1b57a2d2ad501e8e56d1fbbff0a61645e340c6/diff",
                "WorkDir": "/var/lib/docker/overlay2/0b747104a0a8deaef8824f23cc1b57a2d2ad501e8e56d1fbbff0a61645e340c6/work"
            },

3、管理镜像常用命令

ls ————列出镜像
build ————构建镜像来自Dockerfile
histiry ————查看镜像历史
inspect ————显示一个或多个镜像详细信息
pull ————从镜像仓库拉取镜像
push ————推送一个镜像到镜像仓库
rm ————移除一个或多个镜像
prune ————移除未使用的镜像。没有被标记或被任何容器引用的
tag ————创建一个引用源镜像标记目的镜像
export ————导出容器文件系统到tar归档文件
import ————导入容器文件系统tar归档文件创建镜像
save ————保存一个或多个镜像到一个tar归档文件
load ————加载镜像来自tar归档或标准输入

例子：

[root@linux-node1 ~]# docker image ls        #列出镜像（新的方式）
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              02256cfb0e4b        6 days ago          109MB
centos              latest              1e1148e4cc2c        3 weeks ago         202MB
hello-world         latest              4ab4c602aa5e        3 months ago        1.84kB

[root@linux-node1 ~]# docker images            #列出镜像（老的方式）
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              02256cfb0e4b        6 days ago          109MB
centos              latest              1e1148e4cc2c        3 weeks ago         202MB
hello-world         latest              4ab4c602aa5e        3 months ago        1.84kB

[root@linux-node1 ~]# docker image inspect nginx:latest   #显示镜像信息
[
    {
        "Id": "sha256:02256cfb0e4bd19bdb74a077cee8ab26dd14d2e54402878a848e172a85a5cec7",
        "RepoTags": [
            "nginx:latest"
        ],
        "RepoDigests": [
            "nginx@sha256:726ad789543f7ecededeba6b68147d86aff5d33f9b5c7ddeef0340a389d2f465"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2018-12-26T23:20:18.874449006Z",
        "Container": "38acc26b719d83b9a8895e34c3241ffb4e7b242037398cb495dacbd87f6e98cd",
        "ContainerConfig": {
            "Hostname": "38acc26b719d",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.15.8-1~stretch",
                "NJS_VERSION=1.15.8.0.2.7-1~stretch"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "#(nop) ",
                "CMD [\"nginx\" \"-g\" \"daemon off;\"]"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:86e6b30c0d2583dd451dd10582dd644cda524e5f1aac743fa3d8efb896f271be",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "DockerVersion": "18.06.1-ce",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.15.8-1~stretch",
                "NJS_VERSION=1.15.8.0.2.7-1~stretch"
            ],
            "Cmd": [
                "nginx",
                "-g",
                "daemon off;"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:86e6b30c0d2583dd451dd10582dd644cda524e5f1aac743fa3d8efb896f271be",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 109169260,
        "VirtualSize": 109169260,
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/c9d822f8a4c8219b2b34b594f407bf247bde13299e03a05bd7a0fd0f9dde0317/diff:/var/lib/docker/overlay2/e667dae3d4a0983ebabed19877230ee897748c70575849fa2ea5845c0b5edcf2/diff",
                "MergedDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/merged",
                "UpperDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/diff",
                "WorkDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:ef68f6734aa485edf13a8509fe60e4272428deaf63f446a441b79d47fc5d17d3",
                "sha256:2978900fe42b72766df5e07855abd2bb46bbf6c2f12453fbd8e7dc313ab63978",
                "sha256:3c0285ad7db909a5658daa2f52817b4bc2a344ece95800e965f80e0a1ae547ea"
            ]
        },
        "Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]

[root@linux-node1 ~]# docker inspect nginx       #显示镜像信息
[
    {
        "Id": "sha256:02256cfb0e4bd19bdb74a077cee8ab26dd14d2e54402878a848e172a85a5cec7",
        "RepoTags": [
            "nginx:latest"
        ],
        "RepoDigests": [
            "nginx@sha256:726ad789543f7ecededeba6b68147d86aff5d33f9b5c7ddeef0340a389d2f465"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2018-12-26T23:20:18.874449006Z",
        "Container": "38acc26b719d83b9a8895e34c3241ffb4e7b242037398cb495dacbd87f6e98cd",
        "ContainerConfig": {
            "Hostname": "38acc26b719d",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.15.8-1~stretch",
                "NJS_VERSION=1.15.8.0.2.7-1~stretch"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "#(nop) ",
                "CMD [\"nginx\" \"-g\" \"daemon off;\"]"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:86e6b30c0d2583dd451dd10582dd644cda524e5f1aac743fa3d8efb896f271be",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "DockerVersion": "18.06.1-ce",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "80/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "NGINX_VERSION=1.15.8-1~stretch",
                "NJS_VERSION=1.15.8.0.2.7-1~stretch"
            ],
            "Cmd": [
                "nginx",
                "-g",
                "daemon off;"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:86e6b30c0d2583dd451dd10582dd644cda524e5f1aac743fa3d8efb896f271be",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "maintainer": "NGINX Docker Maintainers <docker-maint@nginx.com>"
            },
            "StopSignal": "SIGTERM"
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 109169260,
        "VirtualSize": 109169260,
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/c9d822f8a4c8219b2b34b594f407bf247bde13299e03a05bd7a0fd0f9dde0317/diff:/var/lib/docker/overlay2/e667dae3d4a0983ebabed19877230ee897748c70575849fa2ea5845c0b5edcf2/diff",
                "MergedDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/merged",
                "UpperDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/diff",
                "WorkDir": "/var/lib/docker/overlay2/e32a7bca511ccdabcb99b6218f89e9d5e86609d15b2ee5b08034686c59a9ec79/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:ef68f6734aa485edf13a8509fe60e4272428deaf63f446a441b79d47fc5d17d3",
                "sha256:2978900fe42b72766df5e07855abd2bb46bbf6c2f12453fbd8e7dc313ab63978",
                "sha256:3c0285ad7db909a5658daa2f52817b4bc2a344ece95800e965f80e0a1ae547ea"
            ]
        },
        "Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]

[root@linux-node1 ~]# docker pull nginx:1.14        #下载一个nginx1.14镜像
1.14: Pulling from library/nginx
177e7ef0df69: Pull complete 
132d4353ecd5: Pull complete 
9482632c8a8f: Pull complete 
Digest: sha256:dbdb714212692aec98c262add7f3f3eddc170ea47cd493d0403145c09c302c31
Status: Downloaded newer image for nginx:1.14

[root@linux-node1 ~]# docker image rm nginx:1.14     #删除nginx:1.14镜像
Untagged: nginx:1.14
Untagged: nginx@sha256:dbdb714212692aec98c262add7f3f3eddc170ea47cd493d0403145c09c302c31
Deleted: sha256:3f55d5bb33f3ae6e7f232c82f3bc09f2aa8029d9d213bf69324c95ac1cb9d7ae
Deleted: sha256:d178dd6080618d71e1b85319821b265d20c422511f59f58f4ad84d6341a497a2
Deleted: sha256:2784880ce5781d29eed1af54c19774de0f6fabd3d63db6e0bd2103d4febedbc0
Deleted: sha256:7b4e562e58dcb7fbe1e27bb274f0ff8bfeb2fd965203380436e159df9f218900


[root@linux-node1 ~]# docker image prune             #移除未使用的镜像
WARNING! This will remove all dangling images.
Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B

4、保存镜像及加载镜像

[root@linux-node1 ~]# docker image save centos > centos.tar        #保存centos镜像到归档tar
[root@linux-node1 ~]# du -sh centos.tar 
201M    centos.tar
[root@linux-node1 ~]# docker image rm centos:latest             #删除centos镜像
Untagged: centos:latest
Untagged: centos@sha256:38777a4106f0072649128ea4236241345a3ed21c55abbbd53bad5342549f6126
Deleted: sha256:1e1148e4cc2c148c6890a18e3b2d2dde41a6745ceb4e5fe94a923d811bf82ddb
Deleted: sha256:071d8bd765171080d01682844524be57ac9883e53079b6ac66707e192ea25956
[root@linux-node1 ~]# docker image load < centos.tar             #加载已归档的镜像
071d8bd76517: Loading layer [==================================================>]  210.2MB/210.2MB
Loaded image: centos:latest

文档更新时间: 2024-06-17 15:26 作者：李延召