ClusterLabs/resource-agents — pull request #59 by gockelhahn (2012-02-26 14:00:27+00:00)
Title: IPaddr2: add support for same ip/netmask on different interfaces

there are some (rare) use cases where you need to attach the same IP address on different interfaces ... later on that could be handled by policy routing

at the moment find_interface() finds all interfaces with the same IP/netmask,
the second IPaddr2 resource would not attach its IP since ip_served() is already "ok" ... afterwards when using ip_stop(), it cannot delete it (error)

there was an ugly but possible workaround by changing the netmask on each resource having the same IP (/32, /31, /30), but that leads into problems on the main routing table ...

with this patch ip_served() would say "ok" only if the specified or found nic serves the wanted IP

however the unique constraint on "ip" was NOT removed ... it is just a warning and might be still ok to check for false configuration since this use case is a rare exception?