"mod_proxy_ajp" | errors

["King Holger (CI/AFP2)" <Holger.King@xxxxxxxxxxxx>]

Hi all,

 

when using "mod_proxy_ajp" of Apache2 2.2.16 in combination with two Apache

Tomcat 6.0.29 servlet containers, we often see the following entries within the

Apache2 error log of the virtual host:

 

[Thu Nov 25 16:17:26 2010] [error] ajp_read_header: ajp_ilink_receive failed

[Thu Nov 25 16:17:26 2010] [error] (120006)APR does not understand this error code: proxy: read response failed from 10.35.32.241:8009 (rb-wcmstc2.de.bosch.com)

[Thu Nov 25 16:17:26 2010] [error] [client 10.35.32.123] proxy: error processing end, referer: https://xxx.dot.com/<context_root>/workflow/dialoges/tasks3.jsp?refresh=1

 

When looking in the central Apache2 error log, we see:

[Thu Nov 25 16:17:26 2010] [error] (70007)The timeout specified has expired: ajp_ilink_receive() can't receive header

 

Additionally, we sporadically see connection switches from one Tomcat

to the other without any understandable reasson (here from "rb-wcmstc2" to "rb-wcmstc1"):

 

10.35.32.123 - - [25/Nov/2010:16:17:31 +0100] "POST /servlet/ClientIO/5cmxicinliar/s6/234 HTTP/1.1" 500 1255 "-" "Jakarta Commons-HttpClient/3.1" "

JSESSIONID=68BE78C5C6A2B9756CED86543095C221.rb-wcmstc2" "68BE78C5C6A2B9756CED86543095C221.rb-wcmstc2" "JSESSIONID=C9F5C78771552AF9C15F1D0064099948.

rb-wcmstc1; Path=/" 4784

 

Might the below timeout be set to short (in combination with the aboe "timeout" error log entry)?

 

The current "mod_proxy_ajp" configuration looks like this:

 

<Proxy balancer://fs4server>

        # One tomcat node has been outcommented due to the following ticket: Help-20100510-651

        BalancerMember ajp://rb-wcmstc1.xxx.dot.com:8009 loadfactor=100 retry=10 route=rb-wcmstc1

        BalancerMember ajp://rb-wcmstc2.xxx.dot.com:8009 loadfactor=100 retry=10 route=rb-wcmstc2

 

        ProxySet stickysession=JSESSIONID|jsessionid

        ProxySet lbmethod=byrequests

        ProxySet scolonpathdelim=On

        #ProxySet nofailover=On

        ProxySet timeout=45

</Proxy>

 

Or is there a bug available within the "mod_proxy_ajp" module of Apache2 (details see: http://www.mail-archive.com/users@xxxxxxxxxxxxxxxxx/msg84118.html)

Should we switch to "mod_proxy_http"?