[Linux-cluster] IP-based tie-breaker on a 2-node cluster?

[Andrew Lacey]

> If you have a spare NIC, and the nodes are next to each other, you could
> make them use a cross-over cable for their cluster communication, so they
> would notice that they are both still up even when the switch dies. That's
> what I do.

I had considered this option but I haven't tried it. One thing I was
wondering is how the cluster knows which network interface should get the
cluster service IP address in that situation. Right now, I don't have
anything in my cluster.conf that specifies this, but it just seems to
work. I figured that if I tried to use a crossover cable, what I would
need to do is use /etc/hosts to create hostnames on this little private
network (consisting of just the 2 nodes connected by a cable) and use
those hostnames as the node hostnames in cluster.conf. If I did that,
would the cluster services try to assign the cluster service IP to the
interface with the crossover cable (when obviously what I want is to
assign it to the outward-facing interface)?

-Andrew L