一、实验背景
现在docker将版本分为企业EE版以及社区CE版。
CentOS7.x上的docker安装，主要有两种方式：rpm yum安装和二进制文件安装，其他Linux发行版安装方式类似。
Docker的rpm yum安装需要添加docker官方，然后安装相应的docker社区版，如果内网离线安装的话，需要先在联网机器上下载主包及其依赖，在内网机器搭建本地yum源，执行安装。
Docker的二进制文件安装就省事多了，直接下载官方二进制安装包，编写服务的启动脚本或者Unit文件。
下面我们分别介绍两种安装方式，感受一下安装差异。
二、Docker的yum安装
# yum -y install yum-utils device-mapper-persistent-data lvm2
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
# yum list docker-ce --showduplicates | sort -r
# yum -y install docker-ce-18.06.0.ce
# systemctl start docker
# systemctl status docker
# systemctl enable docker
# docker version
三、Docker的二进制安装
下载docker二进制安装包
# yum -y install wget
# wget https://download.docker.com/linux/static/stable/x86_64/docker-18.06.0-ce.tgz
# tar -zxf docker-18.06.0-ce.tgz
# ll ./docker
# cp ./docker/docker* /usr/bin
创建docker服务的unit文件
# vim /etc/systemd/system/docker.service
##############################################################
[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
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
##############################################
启动docker服务并设为开机自
# systemctl daemon-reload
# systemctl start docker
# systemctl status docker
# systemctl enable docker
# docker info
# docker version
四、参考
https://download.docker.com/linux/static/edge/x86_64
https://docs.docker.com/engine/reference/commandline/dockerd
https://github.com/moby/moby/releases
https://github.com/moby/moby/blob/master/contrib/init/systemd/docker.service
