Multiple tunnels can be created for fail over or load balance purposes.
Each tunnel must terminate at a different DC unless you utilize different egress IPs per tunnel.
Example 1: if only 1 egress IP is shared for 2 tunnels, you need to terminate each tunnel to different head-end.
Example 2: If the tunnels has different egress IP, you can terminate both tunnels to the same head-end.
For other devices that support FQDN tunnel ID:
Multiple tunnels can terminate at the same head-end if FQDN tunnel ID are utilized.