special module for proxy functionality

Hello there,

Is there a module available for Apache 2 which will have more
functionality just like mod_proxy? With mod_proxy there are only 1:1
relations possible - but I need a real dispatching functionality:
From Apache Webserver to more than one target host (with detection of
targets that are down ...).
I just experimented with the BEA Weblogic Module "mod_wl.so" - here it's
possible to configure more than one target hosts... But this module is
not for free and not supported to dispatch to other systems like BEA
WLS/X ...

Regards,
Christian

> Is there a module available for Apache 2 which will have more
> functionality just like mod_proxy? With mod_proxy there are only 1:1
> relations possible - but I need a real dispatching functionality:
> From Apache Webserver to more than one target host (with detection of
> targets that are down ...)

You can do this with mod_rewrite in conjunction with the [proxy] flag.
See http://httpd.apache.org/docs-2.0/en/...e.html#content,
look for "Load Balancing". The example contains everything you want
except the detection of down hosts, but you can add it easely to the
lb.pl script provided there - or google around a bit for an already
enhanced version - i'm quite certain it exists somewhere.

HTH
Christian Ramseyer

> > Is there a module available for Apache 2 which will have more
> > functionality just like mod_proxy? With mod_proxy there are only 1:1
> > relations possible - but I need a real dispatching functionality:
> > From Apache Webserver to more than one target host (with detection of
> > targets that are down ...)
>
> You can do this with mod_rewrite in conjunction with the [proxy] flag.
> See http://httpd.apache.org/docs-2.0/en/...e.html#content,
> look for "Load Balancing". The example contains everything you want
> except the detection of down hosts, but you can add it easely to the
> lb.pl script provided there - or google around a bit for an already
> enhanced version - i'm quite certain it exists somewhere.

while using mod_rewrite with the [P] or [R] flag is a great idea to do
LoadBalancing, the way it is described in the rewriting guide is
suboptimal. external rewriting programs should be avoided at all costs
due to lower performance and the fact that they'll lock up the server
when they lock up or die for any reason.

the right way to do this is:

RewriteEngine On
RewriteMap balance rnd:/path/to/file.txt

RewriteRule (.*) http://${balance:key}/$1 [P]

with /path/to/file.txt containing

key backend1|backend2|backend3...

and having a script updating file.txt.

joachim

>
> while using mod_rewrite with the [P] or [R] flag is a great idea to do
> LoadBalancing, the way it is described in the rewriting guide is
> suboptimal. external rewriting programs should be avoided at all costs
> due to lower performance and the fact that they'll lock up the server
> when they lock up or die for any reason.
>
> the right way to do this is:
>
> RewriteEngine On
> RewriteMap balance rnd:/path/to/file.txt
>
> RewriteRule (.*) http://${balance:key}/$1 [P]
>
> with /path/to/file.txt containing
>
> key backend1|backend2|backend3...
>
> and having a script updating file.txt.
>
> joachim

Good point, using randomized RewriteMaps as described is way more elegant.

regards
christian ramseyer