1. 添加nginx yum repository

先参考: 
nginx官方安装说明 
从nginx官方可以知道， nginx官方为linux各发行版提供了便捷的方法安装.下面简单说下centos下安装nginx的方法.

stable version and mainline version 
由上面可知, nginx官方提供了两种nginx.repo的配置方式， 分别为： 
Pre-Built Packages for Stable version和Pre-Built Packages for Mainline version

添加nginx的yum仓库， 创建文件名为/etc/yum.repos.d/nginx.repo并拷贝粘贴以下配置内容：

stables version的配置如下(喜欢最新稳定版采用)

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

mainline version的配置如下(喜欢开发版采用)

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/mainline/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

其中， 由官方信息可知变量$releasever可替换为对于的版本， 如5, 6, 7分别对应5.x, 6.x, 7.x

Due to differences between how CentOS, RHEL, and Scientific Linux populate the $releasever variable, it is necessary to manually replace $releasever with either 5 (for 5.x) or 6 (for 6.x), depending upon your OS version.

保存退出后， 执行yum makecache出现如下错误信息：

# yum makecache
Loaded plugins: security
base                                                                                               | 3.7 kB     00:00     
base/group_gz                                                                                      | 219 kB     00:00     
base/filelists_db                                                                                  | 6.3 MB     00:06     
base/other_db                                                                                      | 2.8 MB     00:02     
epel                                                                                               | 4.3 kB     00:00     
epel/filelists_db                                                                                  | 8.0 MB     00:07     
epel/other_db                                                                                      | 2.9 MB     00:02     
extras                                                                                             | 3.4 kB     00:00     
extras/filelists_db                                                                                |  38 kB     00:00     
extras/prestodelta                                                                                 | 1.7 kB     00:00     
extras/other_db                                                                                    |  51 kB     00:00     
http://nginx.org/packages/centos/6/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'nginx.org'"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: nginx. Please verify its path and try again
#

由”Couldn’t resolve host ‘nginx.org’”可以知道nginx域名解析不了

解决方法： 从DNS入手， 更改云主机的域名备用DNS  如下：

# vim /etc/resolv.conf

resolv.conf文件内容修改后， 如下：

options timeout:1 attempts:1 rotate
nameserver 10.202.72.118
# nameserver 10.202.72.116
nameserver 114.114.114.114

修改完后， 重新执行以下命令：

# yum makecache

2. yum安装nginx

# yum install nginx

3. 检测nginx是否安装成功

nginx默认的配置目录为/etc/nginx/， 配置文件为/etc/nginx/nginx.conf

# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
#

# nginx -v
nginx version: nginx/1.0.15

浏览器打开http://127.0.0.1, 如下图 

 

发现nginx版本为1.0.15， 版本比较低

执行# yum update进行升级， 然后再检测nginx版本， 如下：

# nginx -v 
nginx version: nginx/1.8.1

此时从nginx官网可知 

  我们已成功安装了官方最新稳定版本的nginx.

p.s. 下面使用mainline version的配置内容来配置/etc/yum.repos.d/nginx.repo, 即如下：

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/mainline/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

然后执行yum makecache来刷新缓存， 好了， 来检查下nginx是否有可更新版本：

# yum info nginx
Loaded plugins: security
Installed Packages
Name        : nginx
Arch        : x86_64
Version     : 1.8.1
Release     : 1.el6.ngx
Size        : 872 k
Repo        : installed
From repo   : nginx
Summary     : High performance web server
URL         : http://nginx.org/
License     : 2-clause BSD-like license
Description : nginx [engine x] is an HTTP and reverse proxy server, as well as
            : a mail proxy server.

Available Packages
Name        : nginx
Arch        : x86_64
Version     : 1.9.14
Release     : 1.el6.ngx
Size        : 820 k
Repo        : nginx
Summary     : High performance web server
URL         : http://nginx.org/
License     : 2-clause BSD-like license
Description : nginx [engine x] is an HTTP and reverse proxy server, as well as
            : a mail proxy server.

显示， 我们可以将nginx1.8.1版本升级到当前最新版本nginx1.9.14, 命令如下：

# yum update nginx

OK， 成功安装当前nginx的最新版本为nginx1.9.14

4. 查看nginx命令用法

# service nginx
Usage: nginx {start|stop|restart|condrestart|try-restart|force-reload|upgrade|reload|status|help|configtest}

常用nginx命令

启动nginx

# service nginx start

停止nginx

# service nginx stop

重启nginx

# service nginx restart