Re: HTTPRedirectoToName

Rob Bloodgood wrote:
>>> I have count1, count3, count4 boxen in my backhand cluster.  count1 is
>>> the "main" box that I'm trying to load balance.  I want count1 to
>>> redirect requests over to count3/count4 based on load, etc.  So I have:
>>>
>>> <LocationMatch "/backhanded/.+">
>>>
>>>     Backhand byAge 2
>>>     # Backhand removeSelf
>>>     Backhand byLoad
>>>
>>>     Backhand HTTPRedirectToName %1S.%1H
>>>
>>>     # Backhand HTTPRedirectToIP
>>>     BackhandLogLevel +netall,+mbcsall,+dcsnall
>>>     # BackhandLogLevel +dcsnall
>>> </LocationMatch>
>>>
>>> Now, looking at the surface, this should work great.  However:
>>>
>>> [Wed Jan 25 13:42:31 2006] [notice] Func executed for (null)
>>> [HTTPRedirectToName(%1S.%1H)] (3 -> 0)
>>> [Wed Jan 25 13:42:31 2006] [notice] New server list: [ ]
>>> [Wed Jan 25 13:42:31 2006] [notice] All funcs executed -> local
>>>
...
>>> It falls off and prevents doing anything useful before the actual,
>>> desired behavior: pick a host that's not me (if conditions are met) and
>>> redirect to it (instead of proxying).
>>>
>>> Have I completely missed the point of this directive, or used it wrong?
>>>

>> Not missed the point.  It prevents the possiblity of an d enless set of
>> redirects. where you just bounce back and forth all the time.
>>
>> The goal is to go to www.exmaple.com and then have that be no-one's
>> hostname.  The three hostnames are www.de.exmaple.com,
>> www.us.example.com and www.jp.exmaple.com.  Once you hit
>> www.XX.exmaple.com, that logic will prevent you from yet again being
>> redirected.
>>
>> Perhaps you already figured that out, I misunderstood and there is a
>> bug?  Certainly possible.  It is one of the least used features in
>> mod_backhand.

OK, there was a missing piece to my story.  The host named count1 is
actually named count, and I was "getting to it" to name it count1.
Well, I thought about that.  The server that I'm renaming to count1 is
getting all its hits with the Host: count.example.com.  So if I change
the apache config so that the local server name is count1, then I have a
chance at the redirect logic letting me through.

So I tried it.

at first, I was disappointed again.  but I had played with my module
loading order a little bit, since I had thought about that while
composing my earlier message.  I had moved mod_perl.c and mod_backhand.c
to be the first two modules in the list.

Since I was having issues, I reversed that step, placed those two
AddModule directives back at the end of the list, and it started working!

*AND*, my supposition was correct!  changing the internal server name to
count1 when the incoming Host: headers all say count.domain.com made
redirection start working for me.

Unfortunately... that does mean that I end up with one additional
redirect for requests I handle "myself" (where redirects to count1
happen to be the same box as the "Host: count").  But that should be
pretty painless in terms of load.

Comments?

L8r,
Rob