Robert Szabo wrote:
Hi Alan,
I should probably state my overall objective for Linux-ha in my
environment.
Thanks. This helps a lot.
Essentially, I plan to have multiple nodes running linux-ha. There
will be probably seven apps that I wish to manage on these two boxes.
4 apps which run in an active/passive fashion, the other 3 will run
active/active but with a twist. These three apps will always run on
both nodes but will never need to tranfer from one node to another,
as the load balancing is handled by the calling clients. What I am
attempting to do is use Linux-ha to provide the framework for
start/stop/monitoring only, as well as restarting the app if it
should happen to fail.
Now I know how you are using the term active/active.
I take it you know how to handle the active/passive case already.
There are two ways you could do this. The most "natural" way is to have
a clone resource for your application. I worry a little about how
your clients reach your active/active applications. How do they address
the machines that run these services? Do they talk to the "real" IP
addresses, or to floating (virtual) addresses that the CRM manages?
I may know what's going on. Your two resources are identical to each
other, but not clones. I think this is confusing some recent (and I
think misguided) changes to the CRM - which try and see what's running
before it starts. Since it can't distinguish which copy is running -
since there is no difference, then I suspect it gets confused.
If you start these services as clone resources with clone_max=2 and
clone_node_max=1, then it will run no more than 2 copies, with no more
than 1 running on any given node.
This is something that Veritas VCS provides for me today, however,
the cost of VCS is extravagant to say the least. VCS does this by
allowing you to specify which nodes are relevent to the resource
group at the service group level.
After you get this running, I'd love to hear a comparison between VCS
and Linux-HA.
Version 2 of Linux-HA is a major upgrade from version 1 and so far it
looks very promising.
Thanks!
--
Alan Robertson <[EMAIL PROTECTED]>
"Openness is the foundation and preservative of friendship... Let me
claim from you at all times your undisguised opinions." - William
Wilberforce
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