[c-nsp] Forcing all HSRP interfaces to failover

[Arie Vayner (avayner)]

Another nice thing for large scale HSRP is to have a master HSRP group,
and have the others track the master's state (removing the need to
process all those keepalives).

If you look here:
http://www.cisco.com/en/US/docs/ios/ipapp/command/reference/iap_s3.html#
wp1062861

You would notice the "standby track group-number" option, which tracks
another group's status, and mimics it's operational status.
This is very useful when you have a very symmetric topology for many
groups.

Arie

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Phil Mayers
Sent: Friday, April 24, 2009 14:30
To: Ross Vandegrift
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Forcing all HSRP interfaces to failover

Ross Vandegrift wrote:
> Hi everyone,
> 
> Is there any good way to have IOS abdicate the active status on all of
> its HSRP interfaces?  Of course I could change each of a few thousand
> SVIs, but I'd like a better way.
> 
> The only thing I can come up with is to create an unnumbered loopback
> just to use as a tracking target.  Admin down that interface when you
> want to take down one of the routers for maintenance.

What platform/IOS? Under later IOS e.g. SXH/SXI on 6500 you can track 
the tracking "objects". We do this:

track 10 interface Vlan4000 ip routing
track 11 interface Vlan4001 ip routing
track 100 stub-object
  default-state up
track 101 list boolean or
  object 10
  object 11

int VlanXX
  standby 0 track 100 decrement 4
  standby 0 track 101 decrement 4
  standby 0 preempt delay reload 180


...and then do:

conf t
track 100
default-state down

...or use an EEM script to put the tracking object "down". Obviously the

EEM script opens up a load more possibilities.

Note you can also do this:

int VlanXX
  standby 0 track 100 shutdown

...which will shutdown the HSRP group, but you'll then have to wait for 
the timers to expire - I prefer the priority decrement with appropriate 
pre-empt statements on the standby/master.

Some versions of IOS have HSRP "follow groups":

http://www.cisco.com/en/US/docs/ios/ipapp/configuration/guide/ipapp_hsrp
.html#wp1055821

...but on the switch platforms e.g. 6500 this seems to work with 
sub-ints only, not SVIs. Sigh.
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