CARP over VLAN over LAGG

[Julien Cigar]

Hello,

I have a "highly available" router/firewall with the following
configuration (1). Those are plugged in two 2930F (with VSF) using LACP.
It works well, except that I have some weird issues with the CARP 
demotion counter when I'm unplugging some interfaces involved in the 
lagg/carp setup, for example if I unplug/replug igb0 and igb1 in this 
case:

(dmesg):
igb0: link state changed to DOWN
igb1: link state changed to DOWN
carp: demoted by 240 to 240 (send error 50 on vlan11)
carp: 11 at vlan11: MASTER -> BACKUP (more frequent advertisement received)
vlan11: deletion failed: 3
igb1: link state changed to UP
igb0: link state changed to UP

then the CARP status stays to BACKUP unless I demote the CARP demotion
counter manually with: sudo sysctl net.inet.carp.demotion=-240:

(dmesg):
carp: demoted by -240 to 0 (sysctl)
carp: 11 at vlan11: BACKUP -> MASTER (preempting a slower master)

I guess this is because it takes some time for lagg/lacp to converge and
thus carp thinks that there is a problematic condition as it experiences
problems with sending announcements..

What it the best way to handle this?

Thanks,
Julien

(1) https://gist.github.com/silenius/577606b596ff1d220bbfd9956d05baef

-- 
Julien Cigar
Belgian Biodiversity Platform (http://www.biodiversity.be)
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