We currently have a monolith where I work, on kubernetes. We are using libcluster to get the nodes the mesh together, and up until now, there has only been one type of node that has every possible dependency and library. It isn’t really sustainable so I’d like to break up some functionality.

The way libcluster works is it gets a list of ips where erlang nodes could be, and then connects them together. Since there could be multiple erlang vms on one machine, it uses a basename@hostname combo for its long names, where the hostname determines what machine it is on, and the basename determines which vm on that machine you want.

In kubernetes every container is just going to have one node on it, so libcluster made a design decision that every erlang node should have the same basename. That’s fine, but then how do I tell the difference between node types in my cluster?

For example, if I have some api nodes, and I have some analytics nodes, and one of the api nodes wants to contact a random analytics node to crunch some data and wait for the results, how do I determine which nodes are “analytics” nodes, when all of the nodes names look like :foo@whatever ?

Up until now I would have just named them api@whatever and analytics@whatever and just done a Node.list and filtered out the analytics nodes, but I don’t see a lot of people doing that so it makes me wonder if there is a better way.