Here's what changes, and what doesn't.
MariaDB plc now owns Galera
Keep support on the cluster you run today, or move to Percona XtraDB Cluster and stay on MySQL.
Your clustering layer can stay open source, stay on MySQL, and stay supported.
The path forward
Moving to MariaDB is a real option, but it means a different database, with its own data dictionary and privilege setup.
It's also not the only option if you wish to remain on MySQL. You built a MySQL cluster, and there are two ways to keep it that way. Neither one requires a rushed decision.
Path 1
Percona MySQL Support covers your Galera cluster exactly as it runs today. No migration, no changes to your setup. You get senior MySQL engineers on call, 24x7x365, so you can plan your next step whenever it makes sense for you.
Path 2
Percona XtraDB Cluster (PXC) is Percona Server for MySQL plus our own actively maintained Galera fork, open source under GPL v2. Percona Server for MySQL is a drop-in replacement for MySQL Community Edition, so you stay on MySQL rather than moving to a different database. And because you are already running Galera, you are not taking on new constraints. Same wsrep settings, same tools, and your schema and user accounts carry over.
What You Get
Senior MySQL engineers, 24x7x365, follow-the-sun. You get a direct answer, not a ticket queue.
Response times as fast as 15 minutes, so small issues stay small.
Your application does not change. You are already running Galera, so queries, wsrep settings, and application logic all come across. The cutover is planned work, not a rebuild, and we do it with you.
Resources