Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 21 Nov 2023 23:14:34 +0000
From:      bugzilla-noreply@freebsd.org
To:        net@FreeBSD.org
Subject:   [Bug 275225] On ARM64 carp preempt not working as expected
Message-ID:  <bug-275225-7501-iTTeXaHv2u@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-275225-7501@https.bugs.freebsd.org/bugzilla/>
References:  <bug-275225-7501@https.bugs.freebsd.org/bugzilla/>

next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D275225

Reid Linnemann <linnemannr@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |linnemannr@gmail.com

--- Comment #1 from Reid Linnemann <linnemannr@gmail.com> ---
I think you've misunderstood net.inet.carp.preempt:

   net.inet.carp.preempt                 Allow virtual hosts to preempt each
                                           other.  When enabled, a vhid in a
                                           backup state would preempt a mas=
ter
                                           that is announcing itself with a
                                           lower advskew.  Disabled by
                                           default.

Here, 'virtual host' refers to the shared address associated with a VHID. T=
his
setting allows a host with multiple VHIDs to assume the master role on all
VHIDs if just one of them fails over. See in carp(4):

     Assume that host A is the preferred master and we are running the
     192.168.1.0/24 prefix on em0 and 192.168.2.0/24 on em1.  This is the
     setup for host A (advskew is above 0 so it could be overwritten in the
     emergency situation from the other host):

           ifconfig em0 vhid 1 advskew 100 pass mekmitasdigoat 192.168.1.1/=
24
           ifconfig em1 vhid 2 advskew 100 pass mekmitasdigoat 192.168.2.1/=
24

     The setup for host B is identical, but it has a higher advskew:

           ifconfig em0 vhid 1 advskew 200 pass mekmitasdigoat 192.168.1.1/=
24
           ifconfig em1 vhid 2 advskew 200 pass mekmitasdigoat 192.168.2.1/=
24

     When one of the physical interfaces of host A fails, advskew is demoted
     to a configured value on all its carp vhids.  Due to the preempt optio=
n,
     host B would start announcing itself, and thus preempt host A on both
     interfaces instead of just the failed one.

It seems likely to me that in your RPI/ROCKPRO setup that your two hosts are
not actually exchanging CARP messages correctly and both believe that they =
are
the lowest advbase for the VHID.

--=20
You are receiving this mail because:
You are the assignee for the bug.=



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-275225-7501-iTTeXaHv2u>