docker学习1：CentOS Docker 安装

参考：
http://www.runoob.com/docker/centos-docker-install.html

CentOS Docker 安装
Docker支持以下的CentOS版本：
CentOS 7 (64-bit)
CentOS 6.5 (64-bit) 或更高的版本




前提条件
目前，CentOS 仅发行版本中的内核支持 Docker。
Docker 运行在 CentOS 7 上，要求系统为64位、系统内核版本为 3.10 以上。
Docker 运行在 CentOS-6.5 或更高的版本的 CentOS 上，要求系统为64位、系统内核版本为 2.6.32-431 或者更高版本。


使用 yum 安装（CentOS 7下）
Docker 要求 CentOS 系统的内核版本高于 3.10 ，查看本页面的前提条件来验证你的CentOS 版本是否支持 Docker 。
通过 uname -r 命令查看你当前的内核版本


[root@huixuan ~]# uname -a 
Linux huixuan 3.10.0-514.el7.x86_64 #1 SMP Tue Nov 22 16:42:41 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
[root@huixuan ~]# 


安装 Docker
Docker 软件包和依赖包已经包含在默认的 CentOS-Extras 软件源里，安装命令如下：


启动 Docker 后台服务
service docker start


之后需要修改：Docker0网桥默认网段
[root@huixuan ~]# ps -ef | grep docker
root      3691     1  0 17:28 ?        00:00:00 /usr/bin/dockerd-current --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current --default-runtime=docker-runc --exec-opt native.cgroupdriver=systemd --userland-proxy-path=/usr/libexec/docker/docker-proxy-current --seccomp-profile=/etc/docker/seccomp.json --selinux-enabled --log-driver=journald --signature-verification=false --storage-driver overlay2
root      3698  3691  0 17:28 ?        00:00:00 /usr/bin/docker-containerd-current -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-timeout 2m --state-dir /var/run/docker/libcontainerd/containerd --shim docker-containerd-shim --runtime docker-runc --runtime-args --systemd-cgroup=true
root      3838  3817  0 17:30 pts/0    00:00:00 grep --color=auto docker
[root@huixuan ~]# 




测试运行 hello-world
[root@huixuan ~]# docker run hello-world
Unable to find image 'hello-world:latest' locally
Trying to pull repository docker.io/library/hello-world ... 
latest: Pulling from docker.io/library/hello-world
9bb5a5d4561a: Pull complete 
Digest: sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Status: Downloaded newer image for docker.io/hello-world:latest


Hello from Docker!
This message shows that your installation appears to be working correctly.


To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.


To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash


Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/


For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/


[root@huixuan ~]# 




使用脚本安装 Docker
1、使用 sudo 或 root 权限登录 Centos。
2、确保 yum 包更新到最新。
yum update




3、执行 Docker 安装脚本。
[root@huixuan ~]# curl -fsSL https://get.docker.com/ | sh
# Executing docker install script, commit: 36b78b2
Warning: the "docker" command appears to already exist on this system.


If you already have Docker installed, this script can cause trouble, which is
why we're displaying this warning and provide the opportunity to cancel the
installation.


执行这个脚本会添加 docker.repo 源并安装 Docker。




4、启动 Docker 进程。
[root@huixuan ~]# service docker start 
Redirecting to /bin/systemctl start docker.service




5、验证 docker 是否安装成功并在容器中执行一个测试的镜像。
[root@huixuan ~]# docker run hello-world


Hello from Docker!
This message shows that your installation appears to be working correctly.


To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.


To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash


Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/


For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/


[root@huixuan ~]# 


到此，docker 在 CentOS 系统的安装完成。






镜像加速
鉴于国内网络问题，后续拉取 Docker 镜像十分缓慢，我们可以需要配置加速器来解决，我使用的是网易的镜像地址：http://hub-mirror.c.163.com。
新版的 Docker 使用 /etc/docker/daemon.json（Linux） 或者 %programdata%\docker\config\daemon.json（Windows） 来配置 Daemon。
请在该配置文件中加入（没有该文件的话，请先建一个）：


[root@huixuan ~]# cat /etc/docker/daemon.json 
{
  "registry-mirrors": ["http://hub-mirror.c.163.com"]
  "bip":"192.168.100.1/24"
}
[root@huixuan ~]#