1.添加yum源（参考官方文档）
To set up the yum repository for RHEL/CentOS, create the file named /etc/yum.repos.d/nginx.repo with the following contents:

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

Replace “OS” with “rhel” or “centos”, depending on the distribution used, and “OSRELEASE” with “6” or “7”, for 6.x or 7.x versions, respectively.

centos7的yum正确姿势是这样：

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/7/$basearch/
gpgcheck=0
enabled=1

2.使用yum安装nginx

yum install nginx

3.查看nginx配置文件

cd /etc/nginx