Remove Cluster Option

[eliasjpr]

Remove Cluster Option

With the addition of the -Dpreview_mt crystal cluster option will not be necessary. Instead we can use the process count setting to easily set the CRYSTAL_WORKERS environment variable when starting the amber server.

[elorest]

I think we should wait for multithreading to be out of preview before removing a feature used by people in production.

[elorest]

Let's add a deprecation warning when clustering is turned on. I can do that.

[eliasjpr]

Yes, this was a ticket to follow up when multithreading is ready

[elorest]

Perfect.

[codered]

Based on the last comment in #1157 , this ticket can be closed. There is no action from the Amber team at this time.