最近在搭建开发的环境，主要是在mac上安装virtualbox虚拟机，然后在centos7.0上面安装nginx服务器和php-fpm以及mariadb数据库，但是当mac异常重启的时候，之前配置的网站就无法访问了，之前对这个问题一直找不出原因，因此只能重新安装nginx，才能得以解决。
今天又碰到这个问题，索性研究一下nginx的配置，发现原来是自己的配置文件没有生效，思索着是不是主配置文件nginx.conf没有生效，一检查果然是，以下是主要配置文件的代码：

<pre>

user nobody;

worker_processes 1;

error_log logs/error.log;

error_log logs/error.log notice;

error_log logs/error.log info;

pid logs/nginx.pid;

events {
worker_connections 1024;
}

http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';

#access_log  logs/access.log  main;

sendfile        on;
#tcp_nopush     on;

#keepalive_timeout  0;
keepalive_timeout  65;
include /etc/nginx/conf.d/*.conf;
#gzip  on;
server {
    listen       80;
    server_name  localhost;

    #charset koi8-r;

    #access_log  logs/host.access.log  main;

    location / {
        root   html;
        index  index.html index.htm;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}


# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
#    listen       8000;
#    listen       somename:8080;
#    server_name  somename  alias  another.alias;

#    location / {
#        root   html;
#        index  index.html index.htm;
#    }
#}


# HTTPS server
#
#server {
#    listen       443 ssl;
#    server_name  localhost;

#    ssl_certificate      cert.pem;
#    ssl_certificate_key  cert.key;

#    ssl_session_cache    shared:SSL:1m;
#    ssl_session_timeout  5m;

#    ssl_ciphers  HIGH:!aNULL:!MD5;
#    ssl_prefer_server_ciphers  on;

#    location / {
#        root   html;
#        index  index.html index.htm;
#    }
#}

}

</pre>
最后，终于找到原因，原来是主要配置文件nginx.conf没有把子配置文件夹conf.d包含进来，所以加上下面这句话，然后重启nginx服务器，问题解决了

添加子配置文件：
<pre>
include /etc/nginx/conf.d/*.conf;
</pre>
重启服务器：
<pre>
service nginx restart
</pre>