1、安装环境
此处在Centos7进行安装，可以使用以下命令查看CentOS版本
lsb_release -a
在 CentOS 7安装docker要求系统为64位、系统内核版本为 3.10 以上，可以使用以下命令查看
uname -r
2、用yum源安装
2.1 查看是否已安装docker列表
yum list installed | grep docker
2.2 安装docker
yum -y install docker
-y表示不询问安装，直到安装成功，安装完后再次查看安装列表
2.3 启动docker
systemctl start docker
2.4 查看docker服务状态
systemctl status docker
以上说明docker安装成功
3、离线安装模式
3.1 安装包官方地址：https://download.docker.com/linux/static/stable/x86_64/
可以先下载到本地，然后通过ftp工具上传到服务器上，或者在服务器上使用命令下载
wget https://download.docker.com/linux/static/stable/x86_64/docker-18.06.3-ce.tgz
3.2 解压
tar -zxvf docker-18.06.3-ce.tgz
3.3 将解压出来的docker文件复制到 /usr/bin/ 目录下
cp docker/* /usr/bin/
3.4 在/etc/systemd/system/目录下新增docker.service文件，内容如下，这样可以将docker注册为service服务
[Unit] Description=Docker Application Container Engine Documentation=https://docs.docker.com After=network-online.target firewalld.service Wants=network-online.target [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 --selinux-enabled=false --insecure-registry=127.0.0.1 ExecReload=/bin/kill -s HUP $MAINPID # Having non-zero Limit*s causes performance problems due to accounting overhead # in the kernel. We recommend using cgroups to do container-local accounting. LimitNOFILE=infinity LimitNPROC=infinity LimitCORE=infinity # Uncomment TasksMax if your systemd version supports it. # Only systemd 226 and above support this version. #TasksMax=infinity TimeoutStartSec=0 # set delegate yes so that systemd does not reset the cgroups of docker containers Delegate=yes # kill only the docker process, not all processes in the cgroup KillMode=process # restart the docker process if it exits prematurely Restart=on-failure StartLimitBurst=3 StartLimitInterval=60s [Install] WantedBy=multi-user.target
此处的--insecure-registry=127.0.0.1（此处改成你私服ip）设置是针对有搭建了自己私服Harbor时允许docker进行不安全的访问，否则访问将会被拒绝。
3.5 启动docker
给docker.service文件添加执行权限
chmod +x /etc/systemd/system/docker.service
重新加载配置文件（每次有修改docker.service文件时都要重新加载下）
systemctl daemon-reload
启动
systemctl start docker
设置开机启动
systemctl enable docker.service
查看docker服务状态
systemctl status docker
上图表示docker已安装成功