什么是Docker？

    Docker是一个构建在LXC之上，基于进程容器的轻量级VM解决方案，实现了一种应用程序级别的资源隔离及配额。Docker起源于PaaS提供商dotCloud 基于go语言开发，遵从Apache2.0开源协议。

    Docker 自开源后受到广泛的关注和讨论，以至于 dotCloud 公司后来都改名为 Docker Inc。

    简单的理解，Docker类似于集装箱，各式各样的货物，经过集装箱的标准化进行托管，而集装箱和集装箱之间没有影响。也就是说，Docker平台就是一个软件集装箱化平台，这就意味着我们自己可以构建应用程序，将其依赖关系一起打包到一个容器中，然后这容器就很容易运送到其他的机器上进行运行，而且非常易于装载、复制、移除，非常适合软件弹性架构。

为什么要使用Docker？

性能上比VM好

一台牛X的服务器，VMWare中启动10个虚拟机，基本上就不能再做其他事情了，大部分CPU和内存资源都耗费在VM内的OS了。而Docker将APP直接放在OS上面，省了大量内存和CPU资源占用，但在效果（沙箱）上与虚拟机完全一致

重复使用、隔离应用

1、根据特定的开发需求，生成一个标准的开发和测试环境，比如机构库的开发，我们需要的环境包括：JDK + Postgresql + tomcat + Nginx + ...

   当我们新来一个开发或者测试人员，我们根据对应的环境，生成一个属于这个开发/测试人员的虚拟机（暂且如此称呼吧），编译部署代码，测试系统都隔离在自身负责的范围。

2、对于系统平台部分，数据库和平台部分，安装在一个环境中，然后我们开发的不同模块都连接到这个虚拟机中公开的接口上，这样，这个环境对我们开发产生积极的影响，核心部分隔离了，应用开发不用再繁琐的部署平台的其他部分了，及保证了核心代码安全，又可以让开发人员专注自身业务而不用管平台底层部分。

Docker熟识

Docker部署及配置

• 安装docker工具

$ cd /etc/yum.repos.d
$ wget https://mirrors.ustc.edu.cn/docker-ce/linux/centos/docker-ce.repo
$ sed -i 's#download.docker.com#mirrors.ustc.edu.cn/docker-ce#g' docker-ce.repo
$ yum -y install docker-ce
$ systemctl enable --now docker.service

• 启动第一个容器

$ docker container run -itd -p 8080:80 nginx:1.21
Unable to find image 'nginx:1.21' locally
1.21: Pulling from library/nginx
1fe172e4850f: Pull complete
35c195f487df: Pull complete
213b9b16f495: Pull complete
a8172d9e19b9: Pull complete
f5eee2cb2150: Pull complete
93e404ba8667: Pull complete
Digest: sha256:859ab6768a6f26a79bc42b231664111317d095a4f04e4b6fe79ce37b3d199097
Status: Downloaded newer image for nginx:1.21
28a074f14de734d565b61d49f8dd1fd005a7da696b381ec3514fe89449ae96b3

• 配置镜像加速器

$ vim /etc/docker/daemon.json
{"registry-mirrors": ["https://registry.docker-cn.com"]
}$ systemctl daemon-reload
$ systemctl restart docker.service

Docker基本指令

• 查看docker版本

[root@localhost ~]# docker version
Client: Docker Engine - CommunityVersion:           25.0.3API version:       1.39 (downgraded from 1.44)Go version:        go1.21.6Git commit:        4debf41Built:             Tue Feb  6 21:17:10 2024OS/Arch:           linux/amd64Context:           defaultServer: Docker Engine - CommunityEngine:Version:          18.09.1API version:      1.39 (minimum version 1.12)Go version:       go1.10.6Git commit:       4c52b90Built:            Wed Jan  9 19:06:30 2019OS/Arch:          linux/amd64Experimental:     false

• 基础资源查看

docker container ls
CONTAINER ID   IMAGE        COMMAND                  CREATED              STATUS          PORTS                                   NAMES
31bdb0575074   nginx:1.21   "/docker-entrypoint.…"   About a minute ago   Up 58 seconds   0.0.0.0:8080->80/tcp, :::8080->80/tcp   romantic_elion$ docker image ls
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
nginx        1.21      fa5269854a5e   12 days ago   142MB$ docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
47ea72ec86c9   bridge    bridge    local
af2d08d73c78   host      host      local
166d963f62c8   none      null      local$ docker volume ls
DRIVER    VOLUME NAME

• 登录远程仓库, 获取拉镜像的权限

$ 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: hlions
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-storeLogin Succeeded$ docker logout
Removing login credentials for https://index.docker.io/v1/

• 搜索镜像

[root@localhost ~]# docker search nginx
NAME                               DESCRIPTION                                     STARS     OFFICIAL
nginx                              Official build of Nginx.                        19668     [OK]
unit                               Official build of NGINX Unit: Universal Web …   24        [OK]
nginx/nginx-ingress                NGINX and  NGINX Plus Ingress Controllers fo…   88        
nginxinc/nginx-unprivileged        Unprivileged NGINX Dockerfiles                  141       
nginx/nginx-prometheus-exporter    NGINX Prometheus Exporter for NGINX and NGIN…   38        
nginxinc/nginx-s3-gateway          Authenticating and caching gateway based on …   6         
nginx/unit                         This repository is retired, use the Docker o…   64        
nginx/nginx-ingress-operator       NGINX Ingress Operator for NGINX and NGINX P…   2         
nginxinc/amplify-agent             NGINX Amplify Agent docker repository           1         
nginx/nginx-quic-qns               NGINX QUIC interop                              1         
nginxinc/ingress-demo              Ingress Demo                                    4         
nginxproxy/nginx-proxy             Automated nginx proxy for Docker containers …   132       
nginxproxy/acme-companion          Automated ACME SSL certificate generation fo…   130       
bitnami/nginx                      Bitnami nginx Docker Image                      183       
bitnami/nginx-ingress-controller   Bitnami Docker Image for NGINX Ingress Contr…   32        
ubuntu/nginx                       Nginx, a high-performance reverse proxy & we…   112       
nginxinc/nginmesh_proxy_debug                                                      0         
nginxproxy/docker-gen              Generate files from docker container meta-da…   16        
nginxinc/mra-fakes3                                                                0         
kasmweb/nginx                      An Nginx image based off nginx:alpine and in…   7         
rancher/nginx-ingress-controller                                                   12        
nginxinc/nginmesh_proxy_init                                                       0         
nginxinc/mra_python_base                                                           0         
nginxinc/ngx-rust-tool                                                             0