CARP over VLAN over LAGG

[Michael Gmelin]

> On 31. Aug 2020, at 10:37, Julien Cigar <julien at perdition.city> wrote:
> 
> On Fri, Aug 28, 2020 at 04:52:01PM +0200, Julien Cigar wrote:
>> 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?
> 
> I'm wondering if setting net.inet.carp.senderr_demotion_factor to "0"
> could be a solution? Are there any downsides of setting this to "0"
> instead of "240"?
> 

Sharing your pf.conf from both hosts could be helpful analyzing the issue.

-m