I agree; it does depend. Our ansible could not infer the DC name from the hostname or ip address of our on-prem hardware. That’s especially true when we are migrating to new hardware or OS and we are adding logical DCs with different names. I suppose it could be embedded in the ansible host file (but you are still maintaining that master file), but we don’t organize our hosts file that way. We are rarely adding a few nodes here or there, so the penalty of a rolling restart is minimal for us.
Sean R. Durity INTERNAL USE From: Bowen Song <bo...@bso.ng> Sent: Thursday, June 2, 2022 12:25 PM To: user@cassandra.apache.org Subject: [EXTERNAL] Re: Topology vs RackDC It really depends on how do you manage your nodes. With automation tools, like Ansible, it's much easier to manage the rackdc file per node. The "master list" doesn't need to exist, because the file is written once and will never get updated. The automation tool will create nodes based on the required DC/rack, and writes that information to the rackdc file during the node provisioning process. It's much faster to add nodes to a large cluster with rackdc file - no rolling restart required. On 02/06/2022 14:46, Durity, Sean R wrote: I agree with Marc. We use the cassandra-topology.properties file (and PropertyFileSnitch) for our deployments. Having a file different on every node has never made sense to me. There would still have to be some master file somewhere from which to generate that individual node file. There is the (slight) penalty that a change in topology requires the distribution of a new file and a rolling restart. Long live the PropertyFileSnitch! 😉 Sean R. Durity From: Paulo Motta <pauloricard...@gmail.com><mailto:pauloricard...@gmail.com> Sent: Thursday, June 2, 2022 8:59 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: [EXTERNAL] Re: Topology vs RackDC It think topology file is better for static clusters, while rackdc for dynamic clusters where users can add/remove hosts without needing to update the topology file on all hosts. On Thu, 2 Jun 2022 at 09:13 Marc Hoppins <marc.hopp...@eset.com<mailto:marc.hopp...@eset.com>> wrote: Hi all, Why is RACKDC preferred for production than TOPOLOGY? Surely one common file is far simpler to distribute than deal with the mucky-muck of various configs for each host if they are in one rack or another and/or one datacentre or another? It is also fairly self-documenting of the setup with the entire cluster there in one file. From what I read in the documentation, regardless of which snitch one implements, cassandra-topology.properties will get read, either as a primary or as a backup...so why not just use topology for ALL cases? Thanks Marc INTERNAL USE
