islanded master master recommendation

I have a question regarding the best way to achieve what I want.

I have two asterisk phone servers which I intend to migrate to live database configuration - much of which can be replicated between the database on each phone server.

Ideally I would have master-master replication where each node would act independently if network connectivity was lost and each would re-sync changes to the other when connection is re-established.

I have installed MariaDB-server (10.1.28-1.el7.centos).

I see that the galera setup wants 3 nodes (which isn't particularly a problem to host a database on a 3rd device) but this method seems to want at least 2 nodes running to function. In my case my priority is having the system function with only 1 node operational (particularly the local one).

Will a standard galera setup work that way?

If not, what are the best ways to achieve that functionality?

John