根据https://www.cnblogs.com/zyxnhr/p/11825331.html这个文章，已经可以正常安装一个docker服务
查看Docker状态
[root@docker-server3 ~]# systemctl status docker
● docker.service - Docker Application Container Engine Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled) Active: active (running) since Sat 2019-11-09 11:29:15 EST; 5h 4min ago Docs: https://docs.docker.com Main PID: 73627 (dockerd) Tasks: 13 Memory: 45.7M CGroup: /system.slice/docker.service └─73627 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
在执行yum -y install docker-ce的动作的时候，已经安装好了docker的客户端和服务端
[root@docker-server3 ~]# docker version
Client: Docker Engine - Community #客户端引擎社区版 Version: 19.03.4 #版本 API version: 1.40 Go version: go1.12.10 Git commit: 9013bf583a Built: Fri Oct 18 15:52:22 2019 OS/Arch: linux/amd64 Experimental: false Server: Docker Engine - Community #服务端引擎 Engine: Version: 19.03.4 API version: 1.40 (minimum version 1.12) Go version: go1.12.10 Git commit: 9013bf583a Built: Fri Oct 18 15:50:54 2019 OS/Arch: linux/amd64 Experimental: false containerd: Version: 1.2.10 GitCommit: b34a5c8af56e510852c35414db4c1f4fa6172339 runc: Version: 1.0.0-rc8+dev GitCommit: 3e425f80a8c931f88e6d94a8c831b9d5aa481657 docker-init: Version: 0.18.0 GitCommit: fec3683
docker是一个C/S架构，在执行docker的指令的时候，会默认连接到自己本机的docker -deamon进程
停止掉docker进程
[root@docker-server3 ~]# ps -ef|grep docker
root 73627 1 0 11:29 ? 00:00:13 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock root 73992 73963 0 16:25 pts/1 00:00:00 vi /lib/systemd/system/docker.service
[root@docker-server3 ~]# systemctl stop docker
[root@docker-server3 ~]# systemctl status docker
● docker.service - Docker Application Container Engine Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled) Active: inactive (dead) Docs: https://docs.docker.com
[root@docker-server3 ~]# docker version
Client: Docker Engine - Community Version: 19.03.4 API version: 1.40 Go version: go1.12.10 Git commit: 9013bf583a Built: Fri Oct 18 15:52:22 2019 OS/Arch: linux/amd64 Experimental: false Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? #显示无法连接Docker daemon，连接的方式是基于文件套接字连接
客户端使用套接字连接，不需要监听任何端口，只需要读取/var/run/docker.sock这个文件
[root@docker-server3 ~]# ll /var/run/docker.sock
srw-rw---- 1 root docker 0 Nov 9 17:01 /var/run/docker.sock
默认是监听本地的套接字文件，也可以使用网络套接字，需要修改启动文件
[root@docker-server3 ~]# vi /lib/systemd/system/docker.service
[Service] Type=notify # the default is not to use systemd for cgroups because the delegate issues still # exists and systemd currently does not support the cgroup feature set required # for containers run by docker ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock #fd:// 表示监听的本地套接字 ExecReload=/bin/kill -s HUP $MAINPID TimeoutSec=0 RestartSec=2 Restart=always
配置成成监听网络接口
[Service] Type=notify # the default is not to use systemd for cgroups because the delegate issues still # exists and systemd currently does not support the cgroup feature set required # for containers run by docker ExecStart=/usr/bin/dockerd -H fd:// -H 0.0.0.0:2375 --containerd=/run/containerd/containerd.sock ExecReload=/bin/kill -s HUP $MAINPID TimeoutSec=0 RestartSec=2 Restart=always
[root@docker-server3 ~]# systemctl daemon-reload
[root@docker-server3 ~]# systemctl restart docker
[root@docker-server3 ~]# netstat -ntlp
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1415/master tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 29852/sshd tcp6 0 0 ::1:25 :::* LISTEN 1415/master tcp6 0 0 :::2375 :::* LISTEN 74333/dockerd #docker的网络套接字就配置完成 tcp6 0 0 :::22 :::* LISTEN 29852/sshd
docker的网络套接字就配置完成，客户端就可以连接2375端口，连接docker-daemon，服务端就是开启端口，等着客户端进行访问
[root@docker-server3 ~]# docker -H 192.168.132.133 version或者
[root@docker-server3 ~]# docker -H 192.168.132.133:2375 version
Client: Docker Engine - Community Version: 19.03.4 API version: 1.40 Go version: go1.12.10 Git commit: 9013bf583a Built: Fri Oct 18 15:52:22 2019 OS/Arch: linux/amd64 Experimental: false Server: Docker Engine - Community Engine: Version: 19.03.4 API version: 1.40 (minimum version 1.12) Go version: go1.12.10 Git commit: 9013bf583a Built: Fri Oct 18 15:50:54 2019 OS/Arch: linux/amd64 Experimental: false containerd: Version: 1.2.10 GitCommit: b34a5c8af56e510852c35414db4c1f4fa6172339 runc: Version: 1.0.0-rc8+dev GitCommit: 3e425f80a8c931f88e6d94a8c831b9d5aa481657 docker-init: Version: 0.18.0 GitCommit: fec3683
docker在开启网络套接字，默认是没有任何验证的，需要安全配置，否则会很危险，生产中也不会使用网络套接字来管理所有的docker客户端，默认使用本地的文件套接字管理自己的docker服务端，如果需要管理所有的docker，可以借助K8S平台进行管理
博主声明：本文的内容来源主要来自誉天教育晏威老师，由本人实验完成操作验证，需要的博友请联系誉天教育（http://www.yutianedu.com/），获得官方同意或者晏老师（https://www.cnblogs.com/breezey/）本人同意即可转载，谢谢！