docker學習1：CentOS Docker 安裝

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

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




前提條件
目前，CentOS 僅發行版本中的內核支持 Docker。
Docker 運行在 CentOS 7 上，要求系統為64位、系統內核版本為 3.10 以上。
Docker 運行在 CentOS-6.5 或更高的版本的 CentOS 上，要求系統為64位、系統內核版本為 2.6.32-431 或者更高版本。


使用 yum 安裝（CentOS 7下）
Docker 要求 CentOS 系統的內核版本高于 3.10 ，查看本頁面的前提條件來驗證你的CentOS 版本是否支持 Docker 。
通過 uname -r 命令查看你當前的內核版本


[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 ~]# 


安裝 Docker
Docker 軟件包和依賴包已經包含在默認的 CentOS-Extras 軟件源里，安裝命令如下：


啟動 Docker 后臺服務
service docker start


之后需要修改：Docker0網橋默認網段
[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 ~]# 




測試運行 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 ~]# 




使用腳本安裝 Docker
1、使用 sudo 或 root 權限登錄 Centos。
2、確保 yum 包更新到最新。
yum update




3、執行 Docker 安裝腳本。
[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.


執行這個腳本會添加 docker.repo 源并安裝 Docker。




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




5、驗證 docker 是否安裝成功并在容器中執行一個測試的鏡像。
[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 系統的安裝完成。






鏡像加速
鑒于國內網絡問題，后續拉取 Docker 鏡像十分緩慢，我們可以需要配置加速器來解決，我使用的是網易的鏡像地址：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） 來配置 Daemon。
請在該配置文件中加入（沒有該文件的話，請先建一個）：


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