Apache reverse-proxy intermittent error 113 - No route to host

Posted by BonkaBonka on Server Fault See other posts from Server Fault or by BonkaBonka
Published on 2009-12-04T16:38:44Z Indexed on 2010/03/25 19:43 UTC
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Filed under:

apache

|

mod-proxy

|

mod-rewrite

I've got an Apache 2.0.52 server on CentOS 4 that front-ends a couple of App servers (mix of Jetty and Tomcat). Apache has a handful of virtual hosts configured like this:

<VirtualHost www1.example.com:443>
    ServerName www1.example.com
    DocumentRoot "/mnt/app_web/html"

    SSLEngine on
    SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP
    SSLCertificateFile      /etc/httpd/conf/ssl.crt/server.crt
    SSLCertificateChainFile /etc/httpd/conf/ssl.crt/chain.crt
    SSLCertificateKeyFile   /etc/httpd/conf/ssl.key/server.key
    SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown downgrade-1.0 force-response-1.0

    RewriteEngine on
    RewriteRule ^/app1/(.*)$ http://app1.example.com:8080/app1/$1 [P,L]
    RewriteRule ^/app2/(.*)$ http://app2.example.com:8080/app2/$1 [P,L]
</VirtualHost>

However, I'm getting the following errors in the logs intermittently:

[Fri Dec 04 07:19:41 2009] [error] (113)No route to host: proxy: HTTP: attempt to connect to 10.0.0.1:8080 (app1.example.com) failed

I initially tried turning off IPv6, and that seemed to largely cure it, but I still have sporadic bursts of these messages.

Additionally, we're running memcache on same front-end and during the times when I'm getting those messages in Apache's log, the following command doesn't work:

echo stats | nc 127.0.0.1 11211

No messages are printed, but neither are the stats printed. I am completely lost as to how to proceed with troubleshooting this. =(

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