11：资源暂时不可用，连接upstream + Bad Gateway (Nginx)

Question

对于我的新服务器上的所有站点，似乎一旦nginx提供了一定数量的流量，它就会开始提供“错误 502 - 错误网关！ ”。

让我们来看看一些日志和配置...

• 操作系统：Ubuntu 16.04（服务器）

• 硬件：6核，12GB内存

• 面板：ISPConfig

• nginx 版本：1.10.3

来自/var/www/example/log/error.log：

11: Resource temporarily unavailable) while connecting to upstream, client: 216.170.123.179, server: example.com, request: "GET /KHFxygk9 HTTP/1.1", upstream: "fastcgi://unix:/var/lib/php7.0-fpm/web3.sock:", host: "example.com", referrer: "http://example.com/"
2017/08/10 06:01:06 [error] 15408#15408: *31372 connect() to unix:/var/lib/php7.0-fpm/web3.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client: 192.3.114.12, server: example.com, request: "GET /jiPNQjwp HTTP/1.1", upstream: "fastcgi://unix:/var/lib/php7.0-fpm/web3.sock:", host: "example.com", referrer: "http://example.com/"

这是我的配置文件：

• /etc/php/7.0/fpm/pool.d/www.conf

---

[www]    
user = www-data
group = www-data

listen = /run/php/php7.0-fpm.sock

listen.owner = www-data
listen.group = www-data

pm = dynamic
pm.max_children = 12    
pm.start_servers = 2    
pm.min_spare_servers = 1    
pm.max_spare_servers = 3    
pm.max_requests = 500

• /etc/nginx/nginx.conf

---

user www-data;
worker_processes auto;
pid /run/nginx.pid;

events {
        worker_connections 768;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;
        gzip_disable "msie6";


        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}

systemctl status php7.0-fpm

? php7.0-fpm.service - The PHP 7.0 FastCGI Process Manager
   Loaded: loaded (/lib/systemd/system/php7.0-fpm.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2017-08-10 04:44:16 UTC; 1h 30min ago
  Process: 20310 ExecReload=/bin/kill -USR2 $MAINPID (code=exited, status=0/SUCCESS)
  Process: 20302 ExecReload=/usr/lib/php/php7.0-fpm-checkconf (code=exited, status=0/SUCCESS)
  Process: 13060 ExecStartPre=/usr/lib/php/php7.0-fpm-checkconf (code=exited, status=0/SUCCESS)
 Main PID: 13070 (php-fpm7.0)
   Status: "Processes active: 20, idle: 12, Requests: 6874, slow: 0, Traffic: 0.3req/sec"
   CGroup: /system.slice/php7.0-fpm.service
       ??13070 php-fpm: master process (/etc/php/7.0/fpm/php-fpm.conf)                      
       ??13072 php-fpm: pool apps-{fpm_domain}                                              
       ??13073 php-fpm: pool apps-{fpm_domain}                                              
       ??13074 php-fpm: pool ispconfig                                                      
       ??13075 php-fpm: pool ispconfig                                                      
       ??13076 php-fpm: pool web1                                                           
       ??13077 php-fpm: pool web1                                                           
       ??13079 php-fpm: pool web2                                                           
       ??13080 php-fpm: pool web3                                                           
       ??13081 php-fpm: pool web3                                                           
       ??13082 php-fpm: pool web4                                                           
       ??13083 php-fpm: pool web4                                                           
       ??13084 php-fpm: pool web5                                                           
       ??13085 php-fpm: pool web5                                                           
       ??13087 php-fpm: pool www                                                            
       ??13088 php-fpm: pool www                                                            
       ??16186 php-fpm: pool web3                                                           
       ??16603 php-fpm: pool web3                                                           
       ??16604 php-fpm: pool web3                                                           
       ??16605 php-fpm: pool web3                                                           
       ??16609 php-fpm: pool web3                                                           
       ??16614 php-fpm: pool web3                                                           
       ??16629 php-fpm: pool web3                                                           
       ??16630 php-fpm: pool web3                                                           
       ??18019 php-fpm: pool web2                                                           
       ??18026 php-fpm: pool web2                                                           
       ??18027 php-fpm: pool web2                                                           
       ??18028 php-fpm: pool web2                                                           
       ??18369 php-fpm: pool web2                                                           
       ??18370 php-fpm: pool web2                                                           
       ??18410 php-fpm: pool web2                                                           
       ??18411 php-fpm: pool web2
       ??18413 php-fpm: pool web2                                                           
Aug 10 04:44:16 web1.example.com systemd[1]: Stopped The PHP 7.0 FastCGI Process Manager.
Aug 10 04:44:16 web1.example.com systemd[1]: Starting The PHP 7.0 FastCGI Process Manager...
Aug 10 04:44:16 web1.example.com systemd[1]: Started The PHP 7.0 FastCGI Process Manager.

Answer 1

这些错误可能是由于缺少允许的最大套接字连接数（大多数默认值为 128）造成的。您可以通过执行查看当前限制，cat /proc/sys/net/core/somaxconn强烈建议增加此限制：

sudo echo "net.core.somaxconn = 65535" | tee -a /etc/sysctl.conf
sudo sysctl -p

并检查它是否已经改变cat /proc/sys/net/core/somaxconn。

此外，这些错误可能是由于缺少传入连接积压队列的数量（大多数默认值为 1000）引起的。检查正在执行的电流限制cat /proc/sys/net/core/netdev_max_backlog。建议增加限制：

sudo echo "net.core.netdev_max_backlog = 65535" | tee -a /etc/sysctl.conf
sudo sysctl -p

并检查它是否已更改 cat /proc/sys/net/core/netdev_max_backlog

注意：如果这些问题出现在您的 OpenVZ VPS 上，则不可能遵循我的建议，因为您无法使用这种类型的虚拟化更改内核参数。在这种情况下，更好的选择是尝试在 php-fpm 池配置中使用端口侦听而不是套接字（例如 listen = 9000）。通过执行检查您的繁忙端口以找到可用的端口sudo netstat -tunlp。

Answer 2

您必须增加 php-fpm max Children's 设置pm.max_children。当前值为 12。

您还可以附上 php-fpm 错误日志吗？