Hello, I’m the author and sole maintainer of Horde.

Just popping in to answer a few of your questions:

Is Horde Registry really distributed?

Yes, it is backed by DeltaCRDT, which has leaderless syncing. Updates that come in are written to an ets table for quick read access. Writes go through the CRDT.

Am I missing something?

It looks like you have configured Horde.NodeListener for your Horde.DynamicSupervisor, but not for your Horde.Registry. I checked, and the guides are not super clear on this, probably owing to the order in which things were built (Horde.NodeListener was added after the guides were written).

Others have mentioned this already, perhaps you should re-read their responses.

Unmaintained

Horde is a library that, as I have learned, has some limitations, but still remains useful to quite a few people (>9k downloads last 7 days). I don’t have the time nor the interest in large development efforts for the project, and there are not a lot of new PRs coming in to the project.

I try to stay on top of things, but the obvious bugs have been ironed out a long time ago, and aside from a few small issues, I would say that Horde is doing fine.

Finally, I will note that Horde is provided free of charge and without any kind of guarantee that it will work.

You may be referring to the old slow pg that pg2 replaced.

The docs for the ‘new’ pg in OTP/23 that deprecated pg2 explicitly states that pg is eventually consistent. The source code for pg indicates it was contributed by WhatsApp.

pg doesn’t have a long list of critical crashing problems unlike some other options mentioned here.

In theory, theory and practice are the same. In practice they are not.

I have been working on a comparable library ProcessHub. Although it’s still in the alpha stage, active development is ongoing.
I’m not going to mention the other libraries already pointed out but alternatively, you may want to explore Swarm.

While you could develop your implementation using the pg module, which is robust and would perform well in your described scenario, you may encounter challenges when the distribution model becomes more complex.