On 2012-05-04, Matt Hamilton <ma...@netsight.co.uk> wrote: > Hi All, > > I'm wondering if anyone has found an elegant solution to the problem > I'm having with interaction between CARP and OSPF. I have a pair of > routers in a failover config. On one side they speak OSPF to a set of > other routers and on the other side use CARP to provide a default > gateway to a set of hosts. There is currently only one CARP interface > at the moment whilst I'm testing this setup, but once in production > there will be around 50-60 vlan interfaces, each with a CARP interface. > > Failover works a charm and if I reboot the primary then the backup > takes over in around 1 second. However when the primary boots back up > and tries to take over then I lose connectivity for about 12-14 > seconds. What I think is happening is that the CARP side is becoming > master before the OSPF side has had a chance to work out neighbors and > take over as the preferred route for packets. > > I know that OSPF can be configured to demote the carp group until it > has at least one active neighbor, but this is too late. The carp > interface is brought up on boot before the ospfd is started. > > Anyone know of a good way to solve this? I'm guessing something along > the lines of demote the carp group *before* the carp interfaces are > brought up (is that even possible?) and then remove the demotion once > OSPF has stabalised. I don't see a nice clean place in the startup > process to do this though unless I hack /etc/netstart or similar which > I don't want to do. > > Thanks, > -Matt > >
You can add '!ifconfig -g carp carpdemote 50' in one of the hostname.carp files, and then -carpdemote in rc.local, maybe give it a bit of a delay for doing this too e.g. '(sleep 300; ifconfig -g carp -carpdemote 50) &'. Untested but it should work ;)
