On 06/07/10 14:12, Peter McGowan wrote:
I'm looking to put together a two-node cluster that will use HP iLOs for
fencing. The systems have their bond0 interfaces connected to the public
LAN, and I was intending to use a private non-routable network (bond1)
purely for cluster communication traffic.
What's confused me is the line in the CMAN FAQ which says "If you are
using per-node power management of any sort where the device is not
shared between cluster nodes, it must be connected to the same network
used by CMAN for cluster communication"
Is anyone able to define "same network" in this context? My iLOs will be
reachable through bond0 (public LAN), but not through bond1 (cluster
network) - does this count as "same network"?
No it doesn't. "Same network" means the same (set of) interfaces that the cluster traffic goes over.
The reason for this is so that in the event of a network outage, only one node has access to the fence device and can fence the other. If the fence device is on a different network (as yours is) then both nodes will be able to fence each other in the event that the cluster communications network breaks. When this happens both nodes will be rebooted, rather than just one.
OK, that makes sense, thanks for the answer. It sounds like using a separate network for cluster communication is generally not such a good idea, as I wouldn't be able to use ping type heuristics either if I decide to use a quorum disk.