connect() 至 unix:/tmp/php-fpm.sock 失败（2：没有此文件或目录）

Question

在我的 vagrant box centtos 7 上，我安装了 php7.0.3 和 nginx 1.9.12。php 配置 www.conf。此文件位于 /usr/local/php/etc/php-fpm.d/ 目录中，其配置如下

user = www
group = www
;listen = /tmp/php-fpm.sock
listen = 127.0.0.1:9000
listen.owner = www
listen.group = www

和 nginx 配置。/usr/local/nginx/conf/vhost/ 目录中的文件 vm.demo.com.conf。其配置如下

server {
    listen       80;
    server_name vm.demo.com;
    index index.html index.htm index.php;
    root  /data/wwwroot/demo;

    location / {
        if (-f $request_filename/index.html){
            rewrite (.*) $1/index.html break;
        }
        if (-f $request_filename/index.php){
            rewrite (.*) $1/index.php;
        }
        if (!-f $request_filename){
            rewrite (.*) /index.php;
        }
    }
    location ~ .*\.(php|php5)?$ {
        #fastcgi_pass unix:/tmp/php-fpm.sock;
        fastcgi_pass 127.0.0.1:9000;

        fastcgi_index index.php;
        include fastcgi.conf;
    }
    access_log  logs/demo.log main;
}

在 nginx conf 中，如果我使用 fastcgi_pass 127.0.0.1:9000 和 php-fpm.conf listen 127.0.0.1:9000，如果我使用套接字配置，它们都可以正常工作：

php www.conf

user = www
group = www
listen = /tmp/php-fpm.sock
listen.owner = www
listen.group = www 

nginx vm.demo.com.conf

    location ~ .*\.(php|php5)?$ {
        fastcgi_pass unix:/tmp/php-fpm.sock;
        fastcgi_index index.php;
        include fastcgi.conf;
    }

nginx 显示 502 Bad gateway。在 nginx error.log 中显示此信息。

2016/03/14 21:17:04 [crit] 4208#0: *5 connect() to unix:/tmp/php-fpm.sock failed (2: No such file or directory) while 
connecting to upstream, client: 192.168.1.101, server: vm.demo.com, request: "GET /test.php HTTP/1.1", 
upstream: "fastcgi://unix:/tmp/php-fpm.sock:", host: "vm.demo.com"
2016/03/14 21:17:04 [crit] 4208#0: *5 connect() to unix:/tmp/php-fpm.sock failed (2: No such file or directory) while 
connecting to upstream, client: 192.168.1.101, server: vm.demo.com, request: "GET /test.php HTTP/1.1", 
upstream: "fastcgi://unix:/tmp/php-fpm.sock:", host: "vm.demo.com"
2016/03/14 21:18:01 [crit] 4208#0: *5 connect() to unix:/tmp/php-fpm.sock failed (2: No such file or directory) while 
connecting to upstream, client: 192.168.1.101, server: vm.demo.com, request: "GET /test.php HTTP/1.1", 
upstream: "fastcgi://unix:/tmp/php-fpm.sock:", host: "vm.demo.com"

当我检查 /tmp/php-fpm.sock 文件时，它存在

[root@vbox1 vhost]# ll /tmp/php-fpm.sock 
srw-rw---- 1 www www 0 Mar 14 21:06 /tmp/php-fpm.sock

这是php和nginx的运行状态：

[root@vbox1 vhost]# systemctl status php-fpm.service
● php-fpm.service - The PHP FastCGI Process Manager
   Loaded: loaded (/etc/systemd/system/php-fpm.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2016-03-14 21:06:27 CST; 42min ago
  Process: 4189 ExecStop=/bin/kill -SIGINT $MAINPID (code=exited, status=0/SUCCESS)
 Main PID: 4198 (php-fpm)
   CGroup: /system.slice/php-fpm.service
           ├─4198 php-fpm: master process (/usr/local/php/etc/php-fpm.conf)
           ├─4199 php-fpm: pool www
           └─4200 php-fpm: pool www

Mar 14 21:06:27 vbox1 systemd[1]: Started The PHP FastCGI Process Manager.
Mar 14 21:06:27 vbox1 systemd[1]: Starting The PHP FastCGI Process Manager...
[root@vbox1 vhost]# systemctl status nginx.service
● nginx.service - nginx
   Loaded: loaded (/etc/systemd/system/nginx.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2016-03-14 21:06:35 CST; 42min ago
  Process: 4180 ExecStop=/usr/local/nginx/sbin/nginx -s quit (code=exited, status=0/SUCCESS)
  Process: 4206 ExecStart=/usr/local/nginx/sbin/nginx (code=exited, status=0/SUCCESS)
 Main PID: 4207 (nginx)
   CGroup: /system.slice/nginx.service
           ├─4207 nginx: master process /usr/local/nginx/sbin/nginx
           ├─4208 nginx: worker process
           └─4209 nginx: worker process

Mar 14 21:06:35 vbox1 systemd[1]: Starting nginx...
Mar 14 21:06:35 vbox1 systemd[1]: Started nginx.

有人能帮我吗？如果有人遇到同样的问题