Mailing List Archive: [mod_backhand-users] Backhand troubles

Theo,
I was successful in getting backhand compiled as a
DSO on both servers. Added the following lines to
httpd.conf:

# LoadModule foo_module libexec/mod_foo.so
LoadModule status_module libexec/mod_status.so
LoadModule info_module libexec/mod_info.so
LoadModule includes_module libexec/mod_include.so
LoadModule backhand_module libexec/mod_backhand.so
LoadModule speling_module libexec/mod_speling.so
LoadModule rewrite_module libexec/mod_rewrite.so

# Reconstruction of the complete module list from all
available modules
# (static and shared ones) to achieve correct module
execution order.
# [WHENEVER YOU CHANGE THE LOADMODULE SECTION ABOVE
UPDATE THIS, TOO]
ClearModuleList
AddModule mod_env.c
AddModule mod_log_config.c
AddModule mod_mime.c
AddModule mod_negotiation.c
AddModule mod_status.c
AddModule mod_info.c
AddModule mod_include.c
AddModule mod_autoindex.c
AddModule mod_dir.c
AddModule mod_cgi.c
AddModule mod_backhand.c
AddModule mod_asis.c
AddModule mod_imap.c
AddModule mod_actions.c
AddModule mod_speling.c
AddModule mod_userdir.c
AddModule mod_alias.c
AddModule mod_rewrite.c
AddModule mod_access.c
AddModule mod_auth.c
AddModule mod_proxy.c
AddModule mod_so.c
------------------------------------------------
After restarting the server(s) The following log
is produced:
--------------------------------------------------
[Wed Sep 20 15:26:10 2000] [notice] SIGUSR1 received.
Doing graceful restart
[Wed Sep 20 15:26:10 2000] [notice] mod_backhand --
UnixSocketDir set to /usr/local/apache/backhand
[Wed Sep 20 15:26:10 2000] [notice] mod_backhand --
Broadcast 192.168.104.255:4445 added
[Wed Sep 20 15:26:10 2000] [notice] mod_backhand --
Multicast accept 192.168.104.0/24
[Wed Sep 20 15:26:10 2000] [notice]
backhand_init(10888) spawning stats things (PID 10998)
[Wed Sep 20 15:26:10 2000] [notice] Apache/1.3.12
(Unix) balanced_by_mod_backhand/1.1.0 configured --
resuming normal operations
[Wed Sep 20 15:26:11 2000] [notice] child pid 10998
exit signal Segmentation fault (11)
[Wed Sep 20 15:26:11 2000] [warn] long lost child came
home! (pid 10998)
-----------------------------------------------------
I modified the backhand log level to the following:
<Directory xxx/xxx>
Order allow,deny
Allow from all
Backhand byAge
Backhand byRandom
Backhand byLoad
BackhandLogLevel +netall,+mbcsall,+dcsnall
</Directory>

Now the server(s) abends within seconds of starting.
I have several questions:
-Are there any modules that I left out?
-What do I have do in order to debug backhand?
-I gleened references to a status page for backhand,
how do I enable it?
-For my network (192.168.104.xxx) are my multicast
and acceptstats vars set correctly?

<IfModule mod_backhand.c>
UnixSocketDir /usr/local/apache/backhand
MulticastStats 192.168.104.255:4445
AcceptStats 192.168.104.0/24
<Location "/backhand/">
SetHandler backhand-handler
</Location>
</IfModule>

My head is busted...I don't know what else to check.
-TAJ

=====
*--------------------------------------------------*
* I only do what the voices in my head tell me to!*
*--------------------------------------------------*

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terry jones wrote:
> I was successful in getting backhand compiled as a
> DSO on both servers. Added the following lines to
> httpd.conf:

> ------------------------------------------------
> After restarting the server(s) The following log
> is produced:
> --------------------------------------------------

I notice that you are gracefully restarting your servers. Does it seg fault
when you start apache or only after a graceful restart?

If you gracefully restart your servers too quickly after Apahce starts
initially, bad things can happen. mod_backhand hasn't finished calculating
the speed of the machine by that point and isn't expecting that signal.

> [Wed Sep 20 15:26:10 2000] [notice]
> backhand_init(10888) spawning stats things (PID 10998)
> [Wed Sep 20 15:26:10 2000] [notice] Apache/1.3.12
> (Unix) balanced_by_mod_backhand/1.1.0 configured --
> resuming normal operations
> [Wed Sep 20 15:26:11 2000] [notice] child pid 10998
> exit signal Segmentation fault (11)
> [Wed Sep 20 15:26:11 2000] [warn] long lost child came
> home! (pid 10998)
> -----------------------------------------------------
> I modified the backhand log level to the following:
> BackhandLogLevel +netall,+mbcsall,+dcsnall

> Now the server(s) abends within seconds of starting.
> I have several questions:
> -Are there any modules that I left out?
Nope... Looks good as far as modules are concerned.
> -What do I have do in order to debug backhand?

OK, compile it statically again. Then run gdb /path/to/httpd
at the gdb prompt type:
set follow-fork-mode child
r -X

This will cause gdb to follow the backhand daemon when it forks and the r -X
will run Apache in debugging mode so ti will only service one request at a
time. You should get a interruption due to a seg fault. From that point it
is typical C debugging using gdb. If you are not familiar with that, the
"where" command will yield a complete stck trae (hopefully). Mail that to me
and it will give me a little insight :)

> -I gleened references to a status page for backhand,
> how do I enable it?

You have it enables in your configuration at <Location /backhand/> so visit
http://yoursite/backhand/ (remember the trailing slah).

> -For my network (192.168.104.xxx) are my multicast
> and acceptstats vars set correctly?

Looks good to me.

> <IfModule mod_backhand.c>
> UnixSocketDir /usr/local/apache/backhand
> MulticastStats 192.168.104.255:4445
> AcceptStats 192.168.104.0/24
> <Location "/backhand/">
> SetHandler backhand-handler
> </Location>
> </IfModule>

--
Theo Schlossnagle
1024D/A8EBCF8F/13BD 8C08 6BE2 629A 527E 2DC2 72C2 AD05 A8EB CF8F
2047R/33131B65/71 F7 95 64 49 76 5D BA 3D 90 B9 9F BE 27 24 E7