jean-frederic clere wrote:
What I mean is
Should general support for a query URL be
provided in mod_proxy_balancer? Or should this be left to mod_cluster?
Can you explain more? I don't get the question.
- Should mod_proxy_balancer be extended to provide a balancer
algorithm in which one specifies a backend URL that will provide a
single numeric health metric, throttle the number of such requests via
a time-to-live associated with this information, and balance on this
- Should mod_cluster handle this issue?
- Or both?
>From your response below, it sounds like you're saying it's #2, which
is largely fine and good -- but this raises questions:
- For instance, mod_cluster might leverage special nuances in
AJP, JBoss, and Tomcat, whereas mod_proxy_balancer might provide more
generic support for helath checks on any back end server that can
expose a health metric URL.
- How general is the health check metric in mod_cluster?
Does this require special JBoss nuggets in Tomcat?
- I only care about Tomcat backends myself, but control over the
metric would be good.
When will mod_cluster support health metric based balancing of
How "disruptive" to an existing configuration using
mod_proxy_balancer/mod_proxy_ajp is mod_cluster?
- I'd hope not, i.e. that this is a simple matter of a
pre-designated URL or a very simple standalone socket protocol.
How portable is the mod_cluster code?
- How much needs to be changed?
I say this is largely fine and good as I'd like to see just the
health-metric based balancing algorithm in Apache 2.2.x itself.
- Does it build on Windows? HPUX? AIX?
Does mod_cluster provide yet another approach
top to bottom (separate than mod_jk and mod_proxy/mod_proxy_ajp)?
Mod_cluster is just a balancer for mod_proxy but due to the dynamic
creation of balancers and workers it can't get in the httpd-trunk code
It would seem nice to me if mod_jk and/or
mod_proxy_balancer could do health checks, but you have to draw the
line somewhere on growing any given module and if mod_jk and
mod_proxy_balancer are not going in that direction at some point
mod_cluster may be in my future.