flask 的网站部署了一天， nginx 依然无法与 uwsgi 通讯，系统 Fedora 23。希望搭建过 Flask 环境的大牛看看。

nginx 的配置（开了 81 端口，方便调试）：

[root@localhost ~]# cat /etc/nginx/conf.d/dev.auth.lan.conf 
server
{
    listen          81;
    server_name     dev.auth.lan;
    root            /var/web/dev.auth.lan;

    location /
    {
        include     uwsgi_params;
        uwsgi_pass  127.0.0.1:8000;
    }
}

uwsgi 的配置：

[root@localhost dev.auth.lan]# cat /etc/uwsgi.ini 
[uwsgi]
uid = uwsgi 
gid = uwsgi
pidfile = /run/uwsgi/uwsgi.pid
emperor = /etc/uwsgi.d
stats = /run/uwsgi/stats.sock
emperor-tyrant = true
cap = setgid,setuid

[root@localhost ~]# cat /etc/uwsgi.d/dev.auth.lan.ini 
[uwsgi]

socket = :8000

chdir = /var/web/dev.auth.lan
wsgi-file = manager.py

master = true
process = 10
vacuum = true

daemonize = /var/log/dev.auth.lan.uwsgi.log

nginx 的运行情况（实心圆圈是绿灯）：

[root@localhost ~]# systemctl status nginx -l
● nginx.service - The nginx HTTP and reverse proxy server
   Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
   Active: active (running) since 六 2016-01-30 06:03:28 PST; 25min ago
  Process: 936 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS)
  Process: 861 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
  Process: 848 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)
 Main PID: 991 (nginx)
   CGroup: /system.slice/nginx.service
           ├─991 nginx: master process /usr/sbin/ngin
           └─993 nginx: worker proces

1 月 30 06:03:28 localhost.localdomain systemd[1]: Starting The nginx HTTP and reverse proxy server...
1 月 30 06:03:28 localhost.localdomain nginx[861]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
1 月 30 06:03:28 localhost.localdomain nginx[861]: nginx: configuration file /etc/nginx/nginx.conf test is successful
1 月 30 06:03:28 localhost.localdomain systemd[1]: nginx.service: Failed to read PID from file /run/nginx.pid: Invalid argument
1 月 30 06:03:28 localhost.localdomain systemd[1]: Started The nginx HTTP and reverse proxy server.

uwsgi 的运行情况（也是绿灯）：

[root@localhost ~]# systemctl status uwsgi -l
● uwsgi.service - uWSGI Emperor Service
   Loaded: loaded (/usr/lib/systemd/system/uwsgi.service; enabled; vendor preset: disabled)
   Active: active (running) since 六 2016-01-30 06:32:29 PST; 2s ago
  Process: 2277 ExecStartPre=/bin/chown uwsgi:uwsgi /run/uwsgi (code=exited, status=0/SUCCESS)
  Process: 2274 ExecStartPre=/bin/mkdir -p /run/uwsgi (code=exited, status=0/SUCCESS)
 Main PID: 2281 (uwsgi)
   Status: "The Emperor is governing 1 vassals"
   CGroup: /system.slice/uwsgi.service
           ├─2281 /usr/sbin/uwsgi --ini /etc/uwsgi.ini
           ├─2283 /usr/sbin/uwsgi --ini /etc/uwsgi.ini
           ├─2284 /usr/sbin/uwsgi --ini dev.auth.lan.ini
           └─2285 /usr/sbin/uwsgi --ini dev.auth.lan.ini

1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: your server socket listen backlog is limited to 100 connections
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: your mercy for graceful operations on workers is 60 seconds
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: mapped 145536 bytes (142 KB) for 1 cores
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: *** Operational MODE: single process ***
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: *** no app loaded. going in full dynamic mode ***
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: *** uWSGI is running in multiple interpreter mode ***
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: spawned uWSGI master process (pid: 2284)
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: Sat Jan 30 06:32:29 2016 - [emperor] vassal dev.auth.lan.ini has been spawned
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: spawned uWSGI worker 1 (pid: 2285, cores: 1)
1 月 30 06:32:29 localhost.localdomain uwsgi[2281]: Sat Jan 30 06:32:29 2016 - [emperor] vassal dev.auth.lan.ini is ready to accept requests

端口也确实开了：

[root@localhost ~]# netstat -lpn | grep 8000
tcp        0      0 0.0.0.0:8000            0.0.0.0:*               LISTEN      2284/uwsgi

项目目录下也确实有 manager.py

[root@localhost dev.auth.lan]# pwd
/var/web/dev.auth.lan

[root@localhost dev.auth.lan]# ls -alh
总用量 4.0K
drwxr-xr-x. 3 root root  39 1 月  30 06:36 .
drwxr-xr-x. 3 root root  26 1 月  30 02:32 ..
-rwxr-xr-x. 1 root root 132 1 月  30 06:10 manager.py
drwxr-xr-x. 5 root root  82 1 月  30 05:02 project

[root@localhost dev.auth.lan]# cat manager.py
#!/usr/bin/env python3

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    return "<span style='color:red'>I am app 1</span>"
[root@localhost dev.auth.lan]#

但是用浏览器访问那台服务器的 81 端口，就是报 502 ， nginx 的日志（太长，加了换行进去）：

2016/01/30 06:37:59 [crit] 993#0: *25 connect() to 127.0.0.1:8000 failed 
(13: Permission denied) 
while connecting to upstream, client: 192.168.124.1, 
server: dev.auth.lan, request: "GET / HTTP/1.1", 
upstream: "uwsgi://127.0.0.1:8000", host: "192.168.124.237:81"