Graham Leggett wrote:
Jim Jagielski wrote:
Ideally, it would be nice if we had better insight on the
actual health of the backends than a simple "do they respond
to OPTIONS * and how long does it take", but that's pretty
much all we can do unless go full-on multicasting of info
ala mod_backhand... At least the balancer is setup to allow
for load balancing based on that, if the submodule/provider
actually existed :)
Is there anything stopping us going the multicasting route, say by
adding a hook or hooks of some kind to proxy that keeps track of known
server states?
A dedicated module could then have it's job as handling the
multicasting and letting the rest of the server know if a server is on
or off the air, in realtime.
The proxy can then just say "which of these servers should I connect
to?", and the hook will return the suggested ones in the given order.
As a dedicated module, people who don't need it can turn it off or not
build it.
this is an idea I've been sitting on for a couple of years now.
Tomcat's cluster can also multicast more than just that the node is
alive, it can broadcast, what applications (URL contexts) are available,
how many threads are in use, what the server load is etc. It can even
broadcast automount points, or when applications are being taken
offline, while the server is still up.
Filip
