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Re: Webserver Redundacy



On Thu, Mar 01, 2007 at 06:15:42AM -0500, Miles Fidelman wrote:
> Something just occurred to me:
> 
> After wading through all the discussions of advertising multiple IPs via 
> DNS vs. using a heartbeat mechanism vs. using LVM, it strikes me that 
> Apache has to be appropriately configured as well.
> 
> If one is using "Listen" commands in your Apache config. file, I don't 
> you can simply tell set your backup (or redundant) daemon to listen on 
> addresses that aren't currently active.  Won't Apache complain at 
> startup about "can't bind to address?"

yes. restarting apache is one of the things that your scripts have to do
when heartbeat notices that the primary machine is down and starts the
takeover procedure.

as someone else said, using "BindAddress *" and "<VirtualHost *>" works,
but not if you're doing IP-address based virtual hosts (e.g. for SSL
sites).

there are several things your scripts have to do when taking over the IP
from the dead machine (and the reverse when the primary comes back up) -
running "/etc/init.d/apache2 reload" is the least of it.


craig

-- 
craig sanders <cas@taz.net.au>

Currently listening to: Shpongle - Monster Hit

"Who will say with confidence that sexual abuse is more
 permanently damaging to children than threatening them
 with the eternal and unquenchable fires of hell?"
               [Richard Dawkins]



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