I just realized this now, looks like Microsoft did it after they bought Citus? Good job!

Citus is a PostgreSQL extension that transforms Postgres into a distributed database.

    -- before adding the first worker node, tell future worker nodes how to reach the coordinator
    SELECT citus_set_coordinator_host('10.0.0.1', 5432);

    -- add worker nodes
    SELECT citus_add_node('10.0.0.2', 5432);
    SELECT citus_add_node('10.0.0.3', 5432);

    -- rebalance the shards over the new worker nodes
    SELECT rebalance_table_shards();