nginx +乘客 + Rails 3.1 = 502 网关不好？

Question

我有最新的 Nginx 与 Passenger、SQLite 和 Rails 3.1 一起运行。不知何故，当我让 Passenger 运行一段时间后，我在访问我的网站时开始收到“502 bad gateway”错误。

这是我的 Nginx 错误日志的片段：

2011/06/27 08:55:33 [error] 20331#0: *11270 upstream prematurely closed connection while reading response header from upstream, client: xxx.xxx.xx.x, server: www.example.com, request: "GET / HTTP/1.1", upstream: "passenger:unix:/passenger_helper_server:", host: "example.com"
2011/06/27 08:55:47 [info] 20331#0: *11273 client closed prematurely connection, so upstream connection is closed too while sending request to upstream, client: xxx.xxx.xx.x, server: www.example.com, request: "GET / HTTP/1.1", upstream: "passenger:unix:/passenger_helper_server:", host: "example.com"

这是我的 passenger-status --show=backtraces 输出：

Thread 'Client thread 7':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 10':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 11':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 12':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 13':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 14':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 15':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 16':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 17':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 18':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 19':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 20':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 21':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 22':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 23':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'Client thread 24':
 in 'Passenger::FileDescriptor Client::acceptConnection()' (HelperAgent.cpp:160)
 in 'void Client::threadMain()' (HelperAgent.cpp:603)

Thread 'MessageServer thread':
 in 'void Passenger::MessageServer::mainLoop()' (MessageServer.h:537)

Thread 'MessageServer client thread 35':
 in 'virtual bool Passenger::BacktracesServer::processMessage(Passenger::MessageServer::CommonClientContext&, boost::shared_ptr<Passenger::MessageServer::ClientContext>&, const std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&)' (BacktracesServer.h:47)
 in 'void Passenger::MessageServer::clientHandlingMainLoop(Passenger::FileDescriptor&)' (MessageServer.h:470)

这是我的 passenger-memory-stats 显示的内容：

---------- Nginx processes ----------
PID    PPID   VMSize   Private  Name
-------------------------------------
16291  1      35.4 MB  0.1 MB   nginx: master process /home/apps/.nginx/sbin/nginx
16292  16291  36.0 MB  0.8 MB   nginx: worker process
16293  16291  35.8 MB  0.5 MB   nginx: worker process
16294  16291  35.8 MB  0.5 MB   nginx: worker process
16295  16291  35.8 MB  0.5 MB   nginx: worker process
### Processes: 5
### Total private dirty RSS: 2.46 MB


----- Passenger processes ------
PID    VMSize    Private   Name
--------------------------------
16251  87.0 MB   0.3 MB    PassengerWatchdog
16254  100.4 MB  1.3 MB    PassengerHelperAgent
16256  41.6 MB   5.7 MB    Passenger spawn server
16259  134.8 MB  0.8 MB    PassengerLoggingAgent
18390  770.4 MB  17.1 MB   Passenger ApplicationSpawner: /home/apps/manager/current
18415  853.3 MB  147.7 MB  Rack: /home/apps/manager/current
18424  790.5 MB  57.2 MB   Rack: /home/apps/manager/current
18431  774.7 MB  18.7 MB   Rack: /home/apps/manager/current
### Processes: 8
### Total private dirty RSS: 248.85 MB

看起来我的 Passenger 和 Nginx 之间的通信有问题吗？

另外，查看 Rails 日志，很明显该请求根本不会到达 Rails，因为没有出现 502 错误的访问日志条目。因此，我最初认为任何 Rack 中间件出现问题的想法都是不可能的。

Answer 1

尝试设置passenger_spawn_method保守 - 显然Passenger默认分叉设置和Rails 3.1存在问题

Answer 2

我刚刚遇到nginx报告的致命的“502 Bad Gateway错误”，web堆栈是Ubuntu 12.04 + Rails 3.2.9 + Passenger 3.0.18 + nginx 1.2.4，我花了2个小时才找到根本原因：

我的rails应用程序不需要数据库支持，所以我只是删除了Gemfile中的gem'sqlite3'，它在开发模式下工作正常，但在生产模式下会导致502 Bad Gateway。

所以在 Gemfile 中添加回 gem 'sqlite3' 后，这样的 502 Bad Gateway 错误就消失了......

Answer 3

我遇到了同样的问题，就我而言，它有助于增加 Nginx 配置文件中的 passenger_max_pool_size 设置。

也许您还可以查看以下帖子，它们也帮助我找到了此解决方案：

• http://whowish-programming.blogspot.com/2011/10/nginx-502-bad-gateway.html
• https://groups.google.com/forum/?fromgroups#!topic /phusion-passenger/fgj6_4VdlLo 和
• https://groups.google.com/forum/?fromgroups#!topic /phusion-乘客/wAQDCrFHHgE

Answer 4

Rails 4 中的情况对我来说是一样的，但是我在 /confirg/secrets.yml 中添加了一个“SECRETKEYBASE”

production:
secretkeybase: # add yours here

Answer 5

VM 中的“V”代表虚拟。另请参阅其他 SO 问题的答案，例如 Linux 下 Java 的虚拟内存使用情况，使用了太多内存。

顶部的 147 MB​​ 并没有暗示任何异常情况。从 Passenger 的角度来看，您的 502 错误意味着工作进程存在其他问题。你应该检查你的 Rails & Nginx 日志文件中寻找线索，也许还有passenger-status --show=backtraces。