一文了解Docker核心概念和安装配置

核心概念

Docker 有三大核心概念,分别是镜像,容器,仓库。

Docker 镜像

Docker 镜像类似于虚拟机的镜像,可以把它理解为一个只读的模板,例如一个镜像可以包含一个基本的操作系统环境,里面仅仅安装了Apache应用程序,可以把它称之为一个Apache镜像。
镜像是创建Docker容器的基础。
通过版本管理和增量文件系统,Docker提供了一套十分简单的机制来更新现有的镜像,用户甚至可以从网上下载一个已经做好的应用镜像,并进行使用。

Docker 容器

Docker容器类似于一个轻量级的沙箱,Docker利用容器来运行和隔离应用。
容器是从镜像创建的应用运行实例,它可以启动,开始停止删除,这些容器彼此相互隔离,互相不可见。
可以把容器看做一个简易版的Linux系统环境,以及运行在其中的应用程序打包而成的盒子。

Docker 仓库

Docker仓库类似于代码仓库,是Docker集中保存镜像文件的场所。
根据保存的镜像是否公开与否,Docker仓库可以分为公开仓库和私有仓库两种形式。

安装Docker引擎

下面的实例,是在Windows下安装docker
1. 访问官网的首页。
https://www.docker.com/

  1. 单击立即适用,选择windows版本的下载

  2. 单击项目进行安装

  3. 进行安装

  4. 检验是否安装成功
    打开powershell 输入docker

这样,windows 版本的docker已经安装完毕

使用Docker镜像

对于docker镜像的使用如下

获取镜像

获取docker镜像,使用如下的命令。
输入命令获取docker镜像

 docker pull ubuntu

从下载的过程可以看到,对于docker容器来说,镜像文件一般由若干层组成,

每一个字符串都是唯一的id,使用docker的pull命令的时候,会一层层的下载相关的镜像,并由上一层镜像指向上上一层的镜像。

查看镜像的信息

使用docke的images命令,查看docker的镜像信息。

上方使用images列出docker的镜像信息。

使用tag命令添加镜像的标签

为了方便于docker镜像的使用,使用docker的tag命令,添加docker的镜像标签。

 docker tag ubuntu:latest myubuntu:laster

使用的效果如下

使用inspect命令查看docker的详细信息

 docker image inspect ubuntu

查看信息如下

PS C:\Users\Administrator\Desktop> docker image inspect ubuntu
[
    {
        "Id": "sha256:74435f89ab7825e19cf8c92c7b5c5ebd73ae2d0a2be16f49b3fb81c9062ab303",
        "RepoTags": [
            "myubuntu:laster",
            "ubuntu:latest"
        ],
        "RepoDigests": [
            "ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2020-06-17T01:20:56.323568224Z",
        "Container": "9477bb1d88721b63e0c6a359eb48a081741a0992480bf34bbcebf4e5734fcf67",
        "ContainerConfig": {
            "Hostname": "9477bb1d8872",
            "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/sh",
                "-c",
                "#(nop) ",
                "CMD [\"/bin/bash\"]"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:5412cfe47ff528df823761788f99a11568e2d25f48a4245a3d67cdc3e564c839",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {}
        },
        "DockerVersion": "18.09.7",
        "Author": "",
        "Config": {
            "Hostname": "",
            "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"
            ],
            "ArgsEscaped": true,
            "Image": "sha256:5412cfe47ff528df823761788f99a11568e2d25f48a4245a3d67cdc3e564c839",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": null
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 73856440,
        "VirtualSize": 73856440,
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/63e1c7f313e414bd5465953da0ceb615cc9c5906c9b539ed164560b18020bc85/diff:/var/lib/docker/overlay2/09f0332099bc97d0052e07879f18271f2c7ea879501498a1eca00711065c9e9a/diff:/var/lib/docker/overlay2/8fef100fbab32d7aa7a3cc70740ef97b45cc9dcfce91453dd10cc502a3fa10f7/diff",
                "MergedDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/merged",
                "UpperDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/diff",
                "WorkDir": "/var/lib/docker/overlay2/3ec5eeae7aa3781aa605fa1a1dc598c39d7774796600b3c1f86e8190c24d5a47/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:e1c75a5e0bfa094c407e411eb6cc8a159ee8b060cbd0398f1693978b4af9af10",
                "sha256:9e97312b63ff63ad98bb1f3f688fdff0721ce5111e7475b02ab652f10a4ff97d",
                "sha256:ec1817c93e7c08d27bfee063f0f1349185a558b87b2d806768af0a8fbbf5bc11",
                "sha256:05f3b67ed530c5b55f6140dfcdfb9746cdae7b76600de13275197d009086bb3d"
            ]
        },
        "Metadata": {
            "LastTagTime": "2020-07-06T13:37:35.064486339Z"
        }
    }
]

使用history命令查看镜像历史

docker history ubuntu
PS C:\Users\Administrator\Desktop> docker history ubuntu
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
74435f89ab78        2 weeks ago         /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B
<missing>           2 weeks ago         /bin/sh -c mkdir -p /run/systemd && echo 'do…   7B
<missing>           2 weeks ago         /bin/sh -c set -xe   && echo '#!/bin/sh' > /…   811B
<missing>           2 weeks ago         /bin/sh -c [ -z "$(apt-get indextargets)" ]     1.01MB
<missing>           2 weeks ago         /bin/sh -c #(nop) ADD file:b2342c7e6665d5ff3…   72.8MB
PS C:\Users\Administrator\Desktop>

搜索相关的镜像

搜索官方带nginx的关键字的镜像

PS C:\Users\Administrator\Desktop> docker search --filter=is-official=true nginx
NAME                DESCRIPTION                STARS               OFFICIAL            AUTOMATED
nginx               Official build of Nginx.   13426               [OK]
PS C:\Users\Administrator\Desktop>

删除和清理镜像

对镜像镜像相关的删除

使用标签删除镜像

 docker rmi ubuntu
PS C:\Users\Administrator\Desktop> docker rmi ubuntu
Untagged: ubuntu:latest
Untagged: ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce
PS C:\Users\Administrator\Desktop>

使用镜像ID删除镜像

PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
myubuntu            laster              74435f89ab78        2 weeks ago         73.9MB
ubuntu              latest              74435f89ab78        2 weeks ago         73.9MB
PS C:\Users\Administrator\Desktop> docker rmi ubuntu
Untagged: ubuntu:latest
Untagged: ubuntu@sha256:35c4a2c15539c6c1e4e5fa4e554dac323ad0107d8eb5c582d6ff386b383b7dce
PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
myubuntu            laster              74435f89ab78        2 weeks ago         73.9MB
PS C:\Users\Administrator\Desktop> docker rmi 74435f89ab78
Untagged: myubuntu:laster
Deleted: sha256:74435f89ab7825e19cf8c92c7b5c5ebd73ae2d0a2be16f49b3fb81c9062ab303
Deleted: sha256:8a8d1f0b34041a66f09e49bdc03e75c2190f606b0db7e08b75eb6747f7b49e11
Deleted: sha256:f1b8f74eff975ae600be0345aaac8f0a3d16680c2531ffc72f77c5e17cbfeeee
Deleted: sha256:27d46ebb54384edbc8c807984f9eb065321912422b0e6c49d6a9cd8c8b7d8ffc
Deleted: sha256:e1c75a5e0bfa094c407e411eb6cc8a159ee8b060cbd0398f1693978b4af9af10
PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
PS C:\Users\Administrator\Desktop>

清理镜像

使用docker镜像来进行清理

PS C:\Users\Administrator\Desktop> docker image prune
WARNING! This will remove all dangling images.
Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B
PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
PS C:\Users\Administrator\Desktop>

创建镜像

基于已有的容器创建镜像

查看运行的容器列表

PS C:\Users\Administrator\Desktop> docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS               NAMES
ff7a974b9771        nginx               "/docker-entrypoint.…"   About a minute ago   Up About a minute   80/tcp              fervent_curie

创建相关的容器

 docker container commit -m "ming" -a "mingming" ff7a974b9771  test:0.1

再次查看

PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
test                0.1                 54a6eb8d4483        5 seconds ago       132MB
ubuntu              latest              74435f89ab78        2 weeks ago         73.9MB
nginx               latest              2622e6cca7eb        3 weeks ago         132MB
PS C:\Users\Administrator\Desktop>

完整的过程如下图

使用模板方式创建

https://download.openvz.org/template/precreated/

下载相关的模板

导入相关的镜像

cat centos-6-x86-minimal.tar.gz|docker import - centos6

使用dockerFile创建

# 构建阶段
FROM node
# 指定工作目录
WORKDIR /
# 指定工作端口
EXPOSE 4000
# 安装gitbook
RUN npm install gitbook -g;
RUN npm install gitbook-cli -g;
# 拉取文件
RUN git clone https://github.com/mySoul8012/SE-Basic-knowledge.git
# 进入目录
WORKDIR /SE-Basic-knowledge
# 初始化镜像
RUN gitbook init
CMD ["gitbook", "serve"]

输入构建的镜像

docker image build -t ming:0.1

保存和载入镜像

存出镜像

PS C:\Users\Administrator\Desktop> docker save -o ubuntu.tar ubuntu
PS C:\Users\Administrator\Desktop>

载入镜像

PS C:\Users\Administrator\Desktop> docker load -i ubuntu.tar
Loaded image: ubuntu:latest
PS C:\Users\Administrator\Desktop> docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
ff7a974b9771        nginx               "/docker-entrypoint.…"   12 minutes ago      Up 12 minutes       80/tcp              fervent_curie
PS C:\Users\Administrator\Desktop> docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
test                0.1                 54a6eb8d4483        10 minutes ago      132MB
ubuntu              latest              74435f89ab78        2 weeks ago         73.9MB
nginx               latest              2622e6cca7eb        3 weeks ago         132MB
PS C:\Users\Administrator\Desktop>

上传镜像

上传镜像到docker

PS C:\Users\Administrator\Desktop> docker push test
The push refers to repository [docker.io/library/test]
53d99160caf2: Preparing
f978b9ed3f26: Preparing
9040af41bb66: Preparing
7c7d7f446182: Preparing
d4cf327d8ef5: Preparing
13cb14c2acd3: Waiting
denied: requested access to the resource is denied
PS C:\Users\Administrator\Desktop>

可以看到拒绝,这里先登录账号

 docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: melovemingming
Password:
Login Succeeded

再进行文件的上传

 docker push melovemingming/nginx

需要注意,上传的镜像格式必须为 用户名/镜像名

查看docker hub 可以看到docker镜像的上传
可以看到docker镜像已经上传

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