CLUSTER_ENDPOINT_URL isn't automatically set with new Meteor Up

[OiCMudkips]

The new Meteor Up doesn't automatically set CLUSTER_ENDPOINT_URL per server. You need to use the old Meteor Up to get this functionality; otherwise your servers won't register themselves properly.

[diegojonio]

I used a script that runs on system startup that set it automatically.
You can have it pre-configured like CLUSTER_ENDPOINT_URL= and in your script you can do: sed -i "s//$(hostname -i)/g" PATH_TO_MUPX/mup.json