So a few things are true: - Cassandra uses IP addresses for internal data structures (in released versions), so duplicating IP nominally means stomping on the wrong host - Cassandra also differentiates broadcast IP from listen IP (local IP) - The broadcast IP is what the other DC is going to see, which probably means internally things wont conflict. It does mean that your local DC traffic is going to go out the NAT to the public IP (I think), which may or may not be a problem - In general this may actually work, but sounds horrible, and I wouldn't do it if it were me.
On Wed, Jun 24, 2020 at 1:26 PM Elliott Sims <elli...@backblaze.com> wrote: > The Cassandra documentation doesn't require IPs to be unique among members > of a cluster, because it's not a Cassandra limitation. Hosts that want to > communicate amongst themselves over the network need non-conflicting IPs, > regardless of application. > > On Wed, Jun 24, 2020 at 5:09 AM manish khandelwal < > manishkhandelwa...@gmail.com> wrote: > >> The nodes within one datacenter will talk on private IPs and for >> communication across data center public ips are used. Does that answer >> your question? or you are asking in terms of network layer. >> >> As per this link >> <https://docs.datastax.com/en/cassandra-oss/3.0/cassandra/configuration/configMultiNetworks.html>, >> there is no mention of private IP to be unique. >> >> In a network one can assign valid private IP. Private IPs can conflict if >> we do not put any restriction on private IP. >> >> Regards >> >> >> On Wed, Jun 24, 2020 at 5:12 PM Erick Ramirez <erick.rami...@datastax.com> >> wrote: >> >>> Putting Cassandra aside, I'm curious to know how you envision that would >>> work from a network perspective. How would the connectivity between servers >>> work? >>> >>>>
