I use dummy interfaces in a VRF as source-interfaces for VXLAN in order to force VXLAN send underlay UDP traffic through the VRF where the dummy interface resides.
However dummy interface has no mtu option so it always gets an MTU of 1500. This will cause an error when the mtu of dummy is not large enough for the VXLAN traffic.
Adding this option in the config template will solve this.