freebsd stable - Aug 2015 - [POSSIBLE BUG] 10-STABLE CARP erroneously becomes master on boot

On Aug 17, 2015 9:22 AM, "Damien Fleuriot" <ml at my.gd>
wrote:
>
> Hello list,
>
>
>
> I'm seeing this very peculiar behaviour between 2 10-STABLE boxes.
>
> Host A is CARP Master with advskew 20 and runs 10.2-BETA1 from 10/07
> Host B is CARP Backup with advskew 150 and runs 10.2-PRERELEASE from 12/08
>
>
> When I configure CARP in rc.conf on host B, it becomes Master on boot, and
> host A remains Master as well.
> When I force a state change on host B (ifconfig vlanx vhid y state
backup),
> it transitions to Backup then again to Master.
>
> When I comment out the CARP configuration in rc.conf , and configure CARP
> manually on host B's interfaces after it boots, it correctly becomes
and
> remains Backup.
>
>
>
> Below is the excerpt from rc.conf pertaining to CARP configuration, the
> only difference between the 2 hosts being their advskew.
>
> Host A
> == BEGIN
>
> ifconfig_vlan410_alias0="vhid 110 pass passhere advskew 20 alias
> 10.104.10.251/32"
>
> == END
>
> Host B
> == BEGIN
>
> ifconfig_vlan410_alias0="vhid 110 pass passhere advskew 150 alias
> 10.104.10.251/32"
>
> == END
Put the IP first, and the vhid stuff last in rc.conf for things to work the
most reliably. And drop the extra alias.

ifconfig_vlan410_alias0="inet 10.104.10.251/32 vhid 110 pass passhere
advskew 150"

CARP requires that all IPs on an interface that are part of the same vhid
to be listed (added) in the exact same order for the vhid to be considered
"the same". That one trips me up all the time when manually adding an
IP to
a CARP pair, and then later rebooting one box as they both think they're
master for that interface, while being a mix of master/backup for the other
interfaces.

Cheers,
Freddie
(running CARP on 2 10-CURRENT boxes and 2 10.1-p13 boxes)

On 17 August 2015 at 18:32, Freddie Cash <fjwcash at gmail.com> wrote:
>
> On Aug 17, 2015 9:22 AM, "Damien Fleuriot" <ml at my.gd>
wrote:
> >
> > Hello list,
> >
> >
> >
> > I'm seeing this very peculiar behaviour between 2 10-STABLE boxes.
> >
> > Host A is CARP Master with advskew 20 and runs 10.2-BETA1 from 10/07
> > Host B is CARP Backup with advskew 150 and runs 10.2-PRERELEASE from
> 12/08
> >
> >
> > When I configure CARP in rc.conf on host B, it becomes Master on boot,
> and
> > host A remains Master as well.
> > When I force a state change on host B (ifconfig vlanx vhid y state
> backup),
> > it transitions to Backup then again to Master.
> >
> > When I comment out the CARP configuration in rc.conf , and configure
CARP
> > manually on host B's interfaces after it boots, it correctly
becomes and
> > remains Backup.
> >
> >
> >
> > Below is the excerpt from rc.conf pertaining to CARP configuration,
the
> > only difference between the 2 hosts being their advskew.
> >
> > Host A
> > == BEGIN
> >
> > ifconfig_vlan410_alias0="vhid 110 pass passhere advskew 20 alias
> > 10.104.10.251/32"
> >
> > == END
> >
> > Host B
> > == BEGIN
> >
> > ifconfig_vlan410_alias0="vhid 110 pass passhere advskew 150 alias
> > 10.104.10.251/32"
> >
> > == END
>
> Put the IP first, and the vhid stuff last in rc.conf for things to work
> the most reliably. And drop the extra alias.
>
> ifconfig_vlan410_alias0="inet 10.104.10.251/32 vhid 110 pass passhere
> advskew 150"
>
> CARP requires that all IPs on an interface that are part of the same vhid
> to be listed (added) in the exact same order for the vhid to be considered
> "the same". That one trips me up all the time when manually
adding an IP to
> a CARP pair, and then later rebooting one box as they both think
they're
> master for that interface, while being a mix of master/backup for the other
> interfaces.
>
> Cheers,
> Freddie
> (running CARP on 2 10-CURRENT boxes and 2 10.1-p13 boxes)
>
Cheers Freddie, will try and keep the thread up to date on the results.