Data node access to Internet requirements

I installed 3 data nodes running MariaDB Galera Clustering and 2 Control Nodes using ClusterControl/HAProxy.  All nodes are connected to the internet/DMZ on one NIC and to a private network on the other. If I disconnect the data nodes from the internet/DMZ for security reasons and bond them to the private network NICs across 2 switches, will this cause any issues now or in the future with managing the cluster with ClusterControl?

The ClusterControl nodes have two NICs each; one on the private network, and the other on the application tier/DMZ side. They are running HAProxy which is exposing the MySQL port to the application tiers in the DMZ.

Thanks for the help!