Thanks all, I stuck with IP addresses. It was just a question to save me having to mess about doing lookups. Given that we only have 6 seeds (3 per DC) it shouldn’t be too much of a headache.
However, I had occasion to start from scratch and noticed a thing. With the first cluster attempt, using ansible to add ‘new’ nodes to the ring: DC1, nodes 1-12 DC2 nodes 1-10 My first seed node was DC1, node 3 but ansible operated in numerical order. Thus, my cluster started with two nodes (DC1 node 1, node 2) which had no idea of one another until DC1 node 3 appeared. When I checked with nodetool status, I saw that each node (after ALL nodes added) , in each DC, OWNS was 15-21%. The second time around, I manually added each node, alternating between each DC, starting with the seeds…then with each regular node (once again alternating). Now the OWNS 8-10.5%. Which seems a lot more realistic. My theory is that, for the first attempt, the two regular nodes which started each owned 100% (tot 200%) and when all the other nodes joined this 200% was divided. AT the time I assumed this was a normal report but now…100%(ish) seems more correct. The ‘scientific’ way to test would be to start a 3rd cluster and join 3 nodes before joining the first seed and see if the owns is 300% divided…but that would be a chore. Anyone have any knowledge if this might have been the case? Marc From: Miles Garnsey <miles.garn...@datastax.com> Sent: Friday, June 24, 2022 1:12 AM To: user@cassandra.apache.org Subject: Re: Seed List EXTERNAL From my understanding, the main thing to be aware of is that Cassandra’s default SeedProvider doesn't resolve multiple A records, so you’re actually limited in terms of the load balancing/DNS configurations you can use. You can however write alternative seed providers which have different (perhaps more appropriate) behaviour, see here<https://github.com/k8ssandra/management-api-for-apache-cassandra/blob/a317ba40fae8e2b11eecde01ad5e6ee15aebdb0f/management-api-agent-4.x/src/main/java/org/apache/cassandra/locator/K8SeedProvider4x.java> for an example. On 23 Jun 2022, at 10:53 pm, Durity, Sean R <sean_r_dur...@homedepot.com<mailto:sean_r_dur...@homedepot.com>> wrote: It can work to use host names. We have done it for temporary clusters where there is at least a theoretical possibility of an ip address change. I don't know all the trade-offs of using host names, since we don't do that for production. Sean R. Durity INTERNAL USE -----Original Message----- From: Marc Hoppins <marc.hopp...@eset.com<mailto:marc.hopp...@eset.com>> Sent: Thursday, June 23, 2022 3:33 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: [EXTERNAL] Seed List Hi guys, Documentation (for almost everything) uses IP addresses for seeds, is it possible to use the FQDN instead for the seeds (cass.yaml)? It is far easier to read/use names. Thanks M
