Connecting cluster with different cookies

[Mikael Pettersson]

On Tue, Aug 10, 2021 at 11:04 AM Roger Lipscombe <roger@REDACTED> wrote:
>
> On Mon, 9 Aug 2021 at 17:21, Raimo Niskanen
> <raimo+erlang-questions@REDACTED> wrote:
> > So, what says the Community?  How important feature is it
> > to be able to connect nodes with different cookies?
>
> Consider another use-case that might inform a wider view: if I've got
> a cluster running with a fixed cookie, and I want to rotate that
> cookie (maybe in place, maybe as I bring new nodes into the cluster
> and retire old ones), how do I do that?

I believe we have that use-case. Our main Erlang cluster is never
supposed to be down (some nodes may be, but never all of them at
once). If we were to have to rotate the cookie we'd need the ability
to migrate nodes and connections incrementally while keeping the nodes
still on the old cookie functional and connected. For that,
set_cookie(OtherNode, OtherCookie) is required. (I'm on vacation now
so can't check if/when we did this, but I'm pretty sure we did not too
long ago.)