虽然Docker官方推荐将docker运行在Ubuntu系统上，但是因为在生产环境中大部分用的还是CentOS（或者Redhat），所以这里也仅记录在CentOS上安装Docker的方法。
Docker安装
方法一：Yum安装
1、更新yum包
# yum update
2、安装必要依赖包
# yum install -y yum-utils device-mapper-persistent-data lvm2
3、添加docker社区版yum源
# wget -O /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo
4、使用yum安装docker
# yum install -y docker-ce docker-ce-cli containerd.io
注：以上命令为安装最新版（latest），如果要安装老版本，可以使用如下命令：
# yum list docker-ce --showduplicates | sort -r # 列出docker-ce的所有版本
# yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io # 根据上一条命令的结果，选择对应的版本安装
方法二：使用安装脚本安装
1、更新yum包
# yum update
2、安装必要依赖包
# yum install -y yum-utils device-mapper-persistent-data lvm2
3、获取安装脚本
# curl -fsSL https://get.docker.com -o get-docker.sh
4、执行脚本安装
# sh get-docker.sh
注：如果要授权给非root用户使用docker，则需使用“sudo usermod -aG docker your-user”命令将非root用户添加至docker用户组中。
方法三：使用RPM包安装
1、更新yum包
# yum update
2、安装必要依赖包
# yum install -y yum-utils device-mapper-persistent-data lvm2
3、下载rpm包
# wget https://download.docker.com/linux/centos/7/x86_64/stable/Packages/[package_name].rpm
4、安装rpm包
# yum install /path/to/[package_name].rpm
启动Docker服务：
[root@centos7 ~]# systemctl start docker
[root@centos7 ~]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
Docker版本：
[root@centos7 ~]# docker version
Client:
Version: 1.13.1
API version: 1.26
Package version: docker-1.13.1-75.git8633870.el7.centos.x86_64
Go version: go1.9.4
Git commit: 8633870/1.13.1
Built: Fri Sep 28 19:45:08 2018
OS/Arch: linux/amd64
Server:
Version: 1.13.1
API version: 1.26 (minimum version 1.12)
Package version: docker-1.13.1-75.git8633870.el7.centos.x86_64
Go version: go1.9.4
Git commit: 8633870/1.13.1
Built: Fri Sep 28 19:45:08 2018
OS/Arch: linux/amd64
Experimental: false
Docker从1.13版本之后采用时间线的方式作为版本号，分为社区版CE和企业版EE。
社区版是免费提供给个人开发者和小型团体使用的，企业版会提供额外的收费服务，比如经过官方测试认证过的基础设施、容器、插件等。
社区版按照stable和edge两种方式发布，每个季度更新stable版本，如17.06，17.09；每个月份更新edge版本，如17.09，17.10。
查看docker信息：
[root@centos7 ~]# docker info
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 1.13.1
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: journald
Cgroup Driver: systemd
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: docker-runc runc
Default Runtime: docker-runc
Init Binary: /usr/libexec/docker/docker-init-current
containerd version: (expected: aa8187dbd3b7ad67d8e5e3a15115d3eef43a7ed1)
runc version: 5eda6f6fd0c2884c2c8e78a6e7119e8d0ecedb77 (expected: 9df8b306d01f59d3a8029be411de015b7304dd8f)
init version: fec3683b971d9c3ef73f284f176672c44b448662 (expected: 949e6facb77383876aeff8a6944dde66b3089574)
Security Options:
seccomp
WARNING: You're not using the default seccomp profile
Profile: /etc/docker/seccomp.json
Kernel Version: 3.10.0-693.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
Number of Docker Hooks: 3
CPUs: 2
Total Memory: 3.686 GiB
Name: centos7.contoso.com
ID: ANO7:53VI:M4ZH:G7KZ:JOZI:A7WC:YZSA:C6JK:5NSB:BCX5:6SMH:TU2S
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
Registries: docker.io (secure)
查看Docker相关目录：
[root@centos7 ~]# rpm -ql docker
/etc/docker
/etc/docker/certs.d
/etc/docker/certs.d/redhat.com
/etc/docker/certs.d/redhat.com/redhat-ca.crt
/etc/docker/certs.d/redhat.io
/etc/docker/certs.d/redhat.io/redhat-ca.crt
/etc/docker/certs.d/registry.access.redhat.com
/etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt
/etc/docker/daemon.json
/etc/docker/seccomp.json
/etc/sysconfig/docker-network
/etc/sysconfig/docker-storage
/etc/sysconfig/docker-storage-setup
/usr/bin/docker-containerd-current
/usr/bin/docker-containerd-shim-current
/usr/bin/docker-ctr-current
/usr/bin/docker-storage-setup
/usr/bin/dockerd-current
/usr/lib/systemd/system/docker-cleanup.service
/usr/lib/systemd/system/docker-cleanup.timer
/usr/lib/systemd/system/docker-storage-setup.service
/usr/lib/systemd/system/docker.service
/usr/lib/udev/rules.d/80-docker.rules
/usr/libexec/docker
/usr/libexec/docker/docker-init-current
/usr/libexec/docker/docker-proxy-current
/usr/libexec/docker/docker-runc-current
/usr/share/bash-completion/completions/docker
/usr/share/doc/docker-1.13.1
/usr/share/doc/docker-1.13.1/AUTHORS
/usr/share/doc/docker-1.13.1/CHANGELOG.md
/usr/share/doc/docker-1.13.1/CONTRIBUTING.md
/usr/share/doc/docker-1.13.1/MAINTAINERS
/usr/share/doc/docker-1.13.1/NOTICE
/usr/share/doc/docker-1.13.1/README-vim-syntax.md
/usr/share/doc/docker-1.13.1/README.md
/usr/share/fish/vendor_completions.d
/usr/share/fish/vendor_completions.d/docker.fish
/usr/share/licenses/docker-1.13.1
/usr/share/licenses/docker-1.13.1/LICENSE
/usr/share/licenses/docker-1.13.1/LICENSE-vim-syntax
/usr/share/man/man1/docker-attach.1.gz
/usr/share/man/man1/docker-build.1.gz
/usr/share/man/man1/docker-commit.1.gz
/usr/share/man/man1/docker-cp.1.gz
/usr/share/man/man1/docker-create.1.gz
/usr/share/man/man1/docker-diff.1.gz
/usr/share/man/man1/docker-events.1.gz
/usr/share/man/man1/docker-exec.1.gz
/usr/share/man/man1/docker-export.1.gz
/usr/share/man/man1/docker-history.1.gz
/usr/share/man/man1/docker-images.1.gz
/usr/share/man/man1/docker-import.1.gz
/usr/share/man/man1/docker-info.1.gz
/usr/share/man/man1/docker-inspect.1.gz
/usr/share/man/man1/docker-kill.1.gz
/usr/share/man/man1/docker-load.1.gz
/usr/share/man/man1/docker-login.1.gz
/usr/share/man/man1/docker-logout.1.gz
/usr/share/man/man1/docker-logs.1.gz
/usr/share/man/man1/docker-network-connect.1.gz
/usr/share/man/man1/docker-network-create.1.gz
/usr/share/man/man1/docker-network-disconnect.1.gz
/usr/share/man/man1/docker-network-inspect.1.gz
/usr/share/man/man1/docker-network-ls.1.gz
/usr/share/man/man1/docker-network-rm.1.gz
/usr/share/man/man1/docker-pause.1.gz
/usr/share/man/man1/docker-port.1.gz
/usr/share/man/man1/docker-ps.1.gz
/usr/share/man/man1/docker-pull.1.gz
/usr/share/man/man1/docker-push.1.gz
/usr/share/man/man1/docker-rename.1.gz
/usr/share/man/man1/docker-restart.1.gz
/usr/share/man/man1/docker-rm.1.gz
/usr/share/man/man1/docker-rmi.1.gz
/usr/share/man/man1/docker-run.1.gz
/usr/share/man/man1/docker-save.1.gz
/usr/share/man/man1/docker-search.1.gz
/usr/share/man/man1/docker-start.1.gz
/usr/share/man/man1/docker-stats.1.gz
/usr/share/man/man1/docker-stop.1.gz
/usr/share/man/man1/docker-storage-setup.1.gz
/usr/share/man/man1/docker-tag.1.gz
/usr/share/man/man1/docker-top.1.gz
/usr/share/man/man1/docker-unpause.1.gz
/usr/share/man/man1/docker-update.1.gz
/usr/share/man/man1/docker-version.1.gz
/usr/share/man/man1/docker-wait.1.gz
/usr/share/man/man1/docker.1.gz
/usr/share/man/man5/Dockerfile.5.gz
/usr/share/man/man5/docker-config-json.5.gz
/usr/share/man/man8/dockerd.8.gz
/usr/share/vim/vimfiles/doc
/usr/share/vim/vimfiles/doc/dockerfile.txt
/usr/share/vim/vimfiles/ftdetect
/usr/share/vim/vimfiles/ftdetect/dockerfile.vim
/usr/share/vim/vimfiles/syntax
/usr/share/vim/vimfiles/syntax/dockerfile.vim
/usr/share/zsh/site-functions
/usr/share/zsh/site-functions/_docker
/var/lib/docker
其中，部分目录如下：
/etc/docker：Docker后台服务进程相关配置主目录，包含certs.d目录和json文件
/etc/docker/certs.d：Docker证书目录，在搭建docker私有仓库时会用到
/etc/sysconfig/docker-network：指定Docker服务的网络配置选项的文件
/etc/sysconfig/docker-storage：指定Docker服务的存储配置选项的文件
/etc/sysconfig/docker-storage-setup：指定Docker后端存储配置选项的文件
/usr/share/doc/docker-1.13.1：存放Docker相关文档的目录
/var/lib/docker：Docker容器和镜像的存放目录
Docker卸载：
1、停止Docker服务
# systemctl stop docker
# systemctl disable docker
2、卸载docker-ce安装包
# yum remove docker-ce -y
3、清理docker目录
# /var/lib/docker
运行第一个Docker：
# docker run hello-world
