Dear Apache2 community, having installed Apache2 2.4.3 in combination with: - mod_proxy_balancer (not "mod_jk"!) - mod_proxy_ajp - mod_proxy
and the following virtual host configuration: BalancerMember ajp://rb-wcmstc1.de.bosch.com:8010 loadfactor=50 ping=5 retry=10 route=rb-wcmstc1 connectiontimeout=5 timeout=300 BalancerMember ajp://rb-wcmstc2.de.bosch.com:8010 loadfactor=50 ping=5 retry=10 route=rb-wcmstc2 connectiontimeout=5 timeout=300 to allow and setup a Tomcat 6 load balancing infrastructure, we regularly see the above configured timeouts in seconds (see http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#proxypass): - request-timeout (300 seconds) - connection-timeout (5 seconds) - cping/cpong-timeout (5 seconds) being exceeded. The Apache2 error logs prove that: (1) [Mon Apr 08 18:23:16.954749 2013] [proxy_ajp:error] [pid 5030:tid 48] (70007)The timeout specified has expired: AH01030: ajp_ilink_receive() can't receive header (2) [Mon Apr 08 18:25:28.422599 2013] [proxy_ajp:error] [pid 6623:tid 52] (70007)The timeout specified has expired: [client 10.25.131.11:28706] AH00897: cping/cpong failed to xx.xx.xx.xxx:8010 (rb-wcmstc1.xx.xxxxx.xxx), referer: https://rb-xxxxx.xx.xxxxx.xxx/fs4webedit/message.jsp (1) might be logged when a request took longer >300 seconds (2) might be logged when ping request took longer >5 seconds Taking a look at the HTTPS Access logs, we see for: (1) a request really taking 300 sec. It leads to the above error log entry at 18:23:16 - five minutes later: xx.xx.xx.xxx - - [08/Apr/2013:18:18:16 +0200] "POST /fs4webedit/Dispatcher HTTP/1.1" 302 295 "..." "F0FDAFA023B323A62813598C985C3AB1.rb-wcmstc1" "-" TLSv1 RC4-MD5 300004793 With an important BUG fix provided since Apache2 version 2.2.22 we have a solution that prevents marking a complete AJP-worker (used for communication between Apache2 and Tomcat) in ERROR state when a single long running request occurred. This bugfix only works when setting the "ping" attribute for the BalancerMember. Details see ChangeLog enclosed: http://www.apache.org/dist/httpd/CHANGES_2.2.22 respectively http://mail-archives.apache.org/mod_mbox/httpd-cvs/201201.mbox/%3c20120104201529.54ea82388...@eris.apache.org%3E Now, our questions are: - what provokes the 2nd error message: "AH01012: ajp_handle_cping_cpong: ajp_ilink_receive failed" (a stop-the-world garbage collection on Tomcat side?) - what are the consequences if that happens? - how to prevent it (simply increasing the ping timeout?) Mit freundlichen Grüßen / Best regards, Holger King CI/AFP2 Tel. 0711-811-59112 BeQIK
