一直坚持了这几天。 尽量提供尽可能多的信息，但请随时索取额外的细节。
我在NAT后面有两个虚拟机，192.168.0.100和192.168.0.102，都运行Ubuntu 11.04 x64。 第一个是映射到外部，是我们的networking服务器，有一个Apache / 2.2.17安装与几个虚拟主机服务静态内容，也有mod_jk负载平衡。 第二个有一个tomcat 7安装几个J2EE REST的web服务，但没有apache – 请求预计将从.100 apache直接传递给.102 tomcat。 我打算编写一个tomcat集群环境。
我的问题：请求到192.168.0.100没有任何问题，但是然后大约需要100秒才能到达.102-那时候apache已经超时了，而tomcat收到的正常处理请求却很正常。 这在使用mod_jk，mod_proxy或mod_ajp_proxy时都会发生。 不知道为什么，因为在任何一台机器中都没有防火墙，所以两者都是可以ping通的 – 更重要的是，有一些NFS共享像魅力一样工作 – 而mod_proxy的经验表明，源自.100的请求正常处理。
另外，为了增加伤害，我们的办公室networking也build立了类似的环境。 一切正常。 唯一的区别？ 我们在办公室没有ip翻译，并且通过内部地址做所有事情 – 不知道是否有任何关联。
一些configuration：
Apache vhost：
<VirtualHost *:80> ServerAdmin webmaster@localhost DocumentRoot /var/www/ ServerName www.example.com ProxyRequests Off <Proxy *> Options Indexes FollowSymLinks MultiViews AllowOverride all Order allow,deny allow from all </Proxy> ProxyPass /bork http://192.168.0.102:8080/bork ProxyPassReverse /bork http://192.168.0.102:8080/bork LogLevel debug CustomLog ${APACHE_LOG_DIR}/api_access.log combined ErrorLog ${APACHE_LOG_DIR}/api_error.log </VirtualHost> Tomcat连接器
<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" /> <Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
还有一个来自apache的debugging日志，使用mod_proxy_ajp进行testing。 在mod_proxy中的行为是相同的，至less在延迟。 请注意，当日志开始再次更新时，tomcat最终会接收并处理请求：
[Sun May 06 14:40:33 2012] [debug] proxy_util.c(1506): [client 188.81.234.2] proxy: ajp: found worker ajp://192.168.0.102:8008/bork for ajp://192.168.0.102:8008/bork/SSOIdentityProviderSoap [Sun May 06 14:40:33 2012] [debug] mod_proxy.c(1015): Running scheme ajp handler (attempt 0) [Sun May 06 14:40:33 2012] [debug] mod_proxy_ajp.c(661): proxy: AJP: serving URL ajp://192.168.0.102:8008/bork/SSOIdentityProviderSoap [Sun May 06 14:40:33 2012] [debug] proxy_util.c(2011): proxy: AJP: has acquired connection for (192.168.0.102) [Sun May 06 14:40:33 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://192.168.0.102:8008/bork/SSOIdentityProviderSoap to 192.168.0.102:8008 [Sun May 06 14:40:33 2012] [debug] proxy_util.c(2193): proxy: connected /bork/SSOIdentityProviderSoap to 192.168.0.102:8008 [Sun May 06 14:40:33 2012] [debug] proxy_util.c(2444): proxy: AJP: fam 2 socket created to connect to 192.168.0.102 [Sun May 06 14:40:33 2012] [debug] ajp_header.c(224): Into ajp_marshal_into_msgb [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[0] [Accept-Encoding] = [gzip,deflate] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[1] [Content-Type] = [text/xml;charset=UTF-8] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[2] [SOAPAction] = [""] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[3] [User-Agent] = [Jakarta Commons-HttpClient/3.1] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[4] [Host] = [www.example.com] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(290): ajp_marshal_into_msgb: Header[5] [Content-Length] = [520] [Sun May 06 14:40:33 2012] [debug] ajp_header.c(450): ajp_marshal_into_msgb: Done [Sun May 06 14:40:33 2012] [debug] mod_proxy_ajp.c(267): proxy: APR_BUCKET_IS_EOS [Sun May 06 14:40:33 2012] [debug] mod_proxy_ajp.c(272): proxy: data to read (max 8186 at 4) [Sun May 06 14:40:33 2012] [debug] mod_proxy_ajp.c(287): proxy: got 520 bytes of data [Sun May 06 14:40:33 2012] [debug] ajp_header.c(687): ajp_read_header: ajp_ilink_received 06 [Sun May 06 14:40:33 2012] [debug] ajp_header.c(697): ajp_parse_type: got 06 [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 2 in child 5916 for worker ajp://192.168.0.100:8008/coding [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1837): proxy: worker ajp://192.168.0.100:8008/coding already initialized [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 2 in child 5916 for (192.168.0.100) [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 3 in child 5916 for worker http://192.168.0.102:8080 [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1837): proxy: worker http://192.168.0.102:8080 already initialized [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 3 in child 5916 for (192.168.0.102) [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 4 in child 5916 for worker ajp://192.168.0.102:8008/bork [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1837): proxy: worker ajp://192.168.0.102:8008/bork already initialized [Sun May 06 14:40:37 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 4 in child 5916 for (192.168.0.102) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 2 in child 5918 for (192.168.0.100) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 3 in child 5918 for worker http://192.168.0.102:8080 [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1837): proxy: worker http://192.168.0.102:8080 already initialized [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 3 in child 5918 for (192.168.0.102) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 4 in child 5918 for worker ajp://192.168.0.102:8008/bork [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1837): proxy: worker ajp://192.168.0.102:8008/bork already initialized [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 4 in child 5918 for (192.168.0.102) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 2 in child 5917 for worker ajp://192.168.0.100:8008/coding [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1837): proxy: worker ajp://192.168.0.100:8008/coding already initialized [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 2 in child 5917 for (192.168.0.100) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 3 in child 5917 for worker http://192.168.0.102:8080 [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1837): proxy: worker http://192.168.0.102:8080 already initialized [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 3 in child 5917 for (192.168.0.102) [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1818): proxy: grabbed scoreboard slot 4 in child 5917 for worker ajp://192.168.0.102:8008/bork [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1837): proxy: worker ajp://192.168.0.102:8008/bork already initialized [Sun May 06 14:40:38 2012] [debug] proxy_util.c(1934): proxy: initialized single connection worker 4 in child 5917 for (192.168.0.102) [Sun May 06 14:42:09 2012] [debug] ajp_header.c(687): ajp_read_header: ajp_ilink_received 04 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(697): ajp_parse_type: got 04 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(516): ajp_unmarshal_response: status = 200 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(537): ajp_unmarshal_response: Number of headers is = 1 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(599): ajp_unmarshal_response: Header[0] [Content-Type] = [text/xml;charset=utf-8] [Sun May 06 14:42:09 2012] [debug] ajp_header.c(609): ajp_unmarshal_response: ap_set_content_type done [Sun May 06 14:42:09 2012] [debug] ajp_header.c(687): ajp_read_header: ajp_ilink_received 03 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(697): ajp_parse_type: got 03 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(687): ajp_read_header: ajp_ilink_received 03 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(697): ajp_parse_type: got 03 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(687): ajp_read_header: ajp_ilink_received 05 [Sun May 06 14:42:09 2012] [debug] ajp_header.c(697): ajp_parse_type: got 05 [Sun May 06 14:42:09 2012] [debug] mod_deflate.c(615): [client 188.81.234.2] Zlib: Compressed 447 to 255 : URL /bork/SSOIdentityProviderSoap [Sun May 06 14:42:09 2012] [debug] mod_proxy_ajp.c(570): proxy: got response from (null) (192.168.0.102) [Sun May 06 14:42:09 2012] [debug] proxy_util.c(2029): proxy: AJP: has released connection for (192.168.0.102) [Sun May 06 14:42:09 2012] [info] [client 188.81.234.2] Request body read timeout
想知道是否有人可以提供一些build议，甚至可能指出任何可怕的，可怕的configuration错误？ 提前致谢！
这几乎可以肯定是DNS。 从.102检查反向DNS查找.100的时间。