httpd failed to start ... new mod_jk's fault
Apache hung up on me today. I tried restarted it, but just got failure notices. Tried rebooting the server and watched /var/log/messages and saw "httpd startup failed".
Yuck. Looked in /var/log/httpd/error_log and saw stuff like the following:
[Fri Aug 25 22:46:53 2006] [error] mod_jk: jk_log_to_file [Fri Aug 25 22:46:53 2006] [4838:16384] [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (909): 0140 73 65 00 A0 08 00 01 30 00 05 00 53 69 64 3D 31 - se.....0...Sid=1\n failed: File too large
I had recently upgraded to version 1.2.18 mod_jk (aka the Tomcat Connector). I looked at the log file for mod_jk...and the file size was about 2 gigs! I did a quick tail command on the file, and saw that it was full of junk like the following:
[Wed Aug 23 16:02:06 2006] [11708:16384] [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1037): 01e0 14 0A 0A D4 D7 36 52 80 3B 17 5F 9B 2F 08 B7 86 - .....6R.;._./...
In otherwords, it was filling up with debug messages. I had left the logging level for mod_jk unspecified, and the docs say that this defaults to "info", which is the minimal amount of logging. Looks like the new version makes "debug" the default.
I was able to fix the problem by moving the large mod_jk.log file to a new location and adding the following line to my httpd.conf file:
JkLogLevel info
After that, I was able to restart httpd and my logs were debug-free.

