Re: [Devil-Linux-discuss] hearbeat operation in Devil-Linux 1.2b2-i586-SMP

[Heiko Z. <he...@zu...>]

Darren Spruell wrote:

> We're hoping to set up a high-availability firewall using Devil-Linux 
> and are happy to see the heartbeat program included now. ;)
>
> Our setup is to be two identical firewall hosts which share a virtual 
> IP address. We want to have a primary and backup firewall host. All 
> traffic should flow through the primary, and upon failure, the backup 
> takes over the VIP. The VIP should always be resident on the active 
> host and the backup releases the VIP when the primary firewall comes 
> back online. We've tested this basic operation by stopping and 
> starting the heartbeat service on on the primary firewall and it seems 
> to work correctly.
>
> I think we are running into a problem when one of these hosts reboots, 
> though. If we power down the primary firewall, the backup successfully 
> takes over the VIP. But when the primary comes back online, it 
> apparently cannot regain the VIP because the generation number is 
> reset to 1 and the backup host is running a different generation 
> number. Here's the log message on the primary firewall when the 
> hearbeat service is started after it reboots:
>
> heartbeat: 2004/09/08_16:19:44 WARN: No Previous generation - starting 
> at 1
> heartbeat: 2004/09/08_16:19:44 info: Heartbeat generation: 1
>
> And as it communicates with the backup firewall, the log message on 
> the backup:
>
> heartbeat: 2004/09/08_16:23:24 ERROR: should_drop_message: attempted 
> replay attack [viawest-test-fw-a.sento.com]? [gen = 1, curgen = 5]
>
> My understanding is that generation numbers are not preserved across 
> reboots and are off-synch if one host is powered off because of 
> devil-linux's volatile memory FS. I don't know if the normal heartbeat 
> operation is to preserve the generation in a file so that it is 
> persistent across reboots. I might not even be going down the right 
> path here. Any ideas?
>
I took a quick look at the linux-ha documenation and stumbled across 
this setting:

> *auto_failback on*
>
> /Required./  For those familiar with Tru64 Unix, heartbeat acts as if 
> in "favored member" mode.  The master listed in the haresources file 
> holds all the resources until a failover, at which time the slave 
> takes over.  When /auto_failback/ is set to *on* once the master comes 
> back online, it will take everything back from the slave.  When set to 
> *off* this option will prevent the master node from re-acquiring 
> cluster resources after a failover. This option is similar to to the 
> obsolete /nice_failback/ option. If you want to upgrade from a cluster 
> which had /nice_failback/ set *off*, to this or later versions, 
> special considerations apply in order to want to avoid requiring a 
> flash cut. Please see the FAQ 
> <http://linux-ha.org/download/faqnstuff.html> for details on how to 
> deal with this situation.
>
>


-- 

Regards
  Heiko Zuerker
  http://www.devil-linux.org