说明

本文只讲述docker离线安装及清理的步骤，关于docker本身的含义、技术特性等不再描述。

根据官网的介绍，在Linux系统中安装docker，可通过在线安装（centos的yum，ubuntu的apt-get等），离线rpm包安装，二进制文件安装等。基于一些环境因素的限制，不能通过在线安装，或rpm离线安装包依赖的问题，二进制文件安装docker显得简单且快速，本文介绍通过二进制文件安装docker。

离线包下载

在官网选择具体的版本，比如本文选择docker-18.09.5版本

mkdir -p ~/tools/docker

cd ~/tools/docker

wget https://download.docker.com/linux/static/stable/x86_64/docker-18.09.5.tgz

用户组配置

# 新建用户组
sudo groupadd docker

# 将登录用户加入到docker用户组中
sudo usermod -aG docker $USER

# 更新用户组
sudo newgrp docker

安装包解压

cd ~/tools/docker

mkdir install-package

# 用于清理
tar -xf docker-18.09.5.tgz -C install-package --strip-components=1

# 解压安装至/usr/local/bin目录下
sudo tar -xf docker-18.09.5.tgz -C /usr/local/bin --strip-components=1

配置docker服务

# 修改docker默认存储路径
sudo mkdir -p ~/data/docker

配置docker.service

在Linux系统配置systemctl管理的服务信息：参考官网文档 。

配置/etc/systemd/system/docker.service文件后，需要执行systemctl daemon-reload重新加载后生效。

sudo cat > /etc/systemd/system/docker.service << EOF
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
#BindsTo=containerd.service
After=network-online.target firewalld.service #containerd.service
Wants=network-online.target
#Requires=docker.socket

[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的启动可选参数，可通过dockerd --help查看
ExecStart=/usr/local/bin/dockerd
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always

# Note that StartLimit* options were moved from "Service" to "Unit" in systemd 229.
# Both the old, and new location are accepted by systemd 229 and up, so using the old location
# to make them work for either version of systemd.
StartLimitBurst=3

# Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd 230.
# Both the old, and new name are accepted by systemd 230 and up, so using the old name to make
# this option work for either version of systemd.
StartLimitInterval=60s

# 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

# Comment TasksMax if your systemd version does not supports it.
# Only systemd 226 and above support this option.
TasksMax=infinity

# 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

[Install]
WantedBy=multi-user.target
EOF

配置daemon.json（可选）

daemon.json是docker.service中ExecStart启动参数的补充，以json格式定义，可通过/usr/local/bin/dockerd --help查看所有的参数

sudo cat >/etc/docker/daemon.json << EOF
{
  "storage-driver": "overlay2",
  "log-driver":"json-file",
  "log-opts":{
    "max-size":"50m",
    "max-file":"2"
  },
  "hosts": ["unix:///var/run/docker.sock"]
}
EOF

启动docker服务

# 因为在/etc/systemd/system/docker.service已经配置了docker.service
# 所以只需重新加载docker服务的配置文件
# 参考关于systemd命令的资料https://blog.51cto.com/xuding/1730952
sudo systemctl daemon-reload

# 通过systemctl启动docker服务
sudo systemctl start docker

# 设置为开机启动
sudo systemctl enable docker

# 通过可执行文件dockerd启动docker服务
# sudo dockerd \
# --exec-root=/var/run/docker \
# --data-root=/home/ubuntu/data/docker \
# &

# 验证开放2375端口
sudo netstat -lntp | grep dockerd

彻底清理docker

# 本文只针对于通过解压安装包的方式进行docker的清理和卸载
# 停止docker服务
sudo systemctl stop docker

# 杀死docker进程（为防止特殊情况下有残留的docker进程）
ps -ef | grep docker | awk '{print $2}' | xargs sudo kill -s 9

# 删除持久化Docker状态的根目录
# 通过docker info |grep 'Docker Root Dir:'命令查看
# 默认值/var/lib/docker，可通过dockerd命令的--data-root选项修改
sudo rm -rf /home/ubuntu/data/docker

# 删除执行状态文件的根目录
# 默认值/var/run/docker，可通过dockerd命令的--exec-root选项修改
sudo rm -rf /var/run/docker
# 删除默认监听的Unix域套接字，容器中的进程可以通过它与Docker守护进程进行通信
sudo rm -rf /var/run/docker.sock
# 删除docker守护进程PID文件
# 默认值/var/run/docker.pid，可通过dockerd命令的-p或--pidfile选项修改
sudo rm -rf /var/run/docker.pid

# 删除系统服务配置文件
sudo rm -rf /etc/systemd/system/docker.service
# 删除docker配置文件
# 默认值/etc/docker/daemon.json，可通过dockerd命令的--config-file选项修改
sudo rm -rf /etc/docker/daemon.json
# 删除自动生成的文件，tls相关配置：~/.docker/{ca.pem,cert.pem,key.pem}
sudo rm -rf ~/.docker/

# 清理可执行文件
ls ~/tools/docker/install-package |awk '{print "/usr/local/bin/"$1}'|xargs sudo rm -rf

参考资料

https://docs.docker.com/install/

https://download.docker.com/linux/static/stable/x86_64/