problem

When you create an isolated network without specifying the MTU in a zone with a specific MTU, it is respected and the network is set with these Zone MTU.
When you create a CKS with the default network and without specifying the MTU it does not respect the zone MTU and create by default 1500 MTU no matter what is fixed in the zone.

versions

Cloudstack 4.20.0.2
CKS :
setup-v1.33.1-calico-x86_64.iso

setup-v1.33.1-calico-x86_64.iso

The steps to reproduce the bug

1. Deploy a zone
2. Specify lower MTU than the default 1500 in zone settings
3. Deploy a CKS in the zone
4. Check the default created isolated network's MTU which are 1500 no matter what.

What to do about it?

No response