Bug when setting MTU on bonding interfaces on Windows system

[Jinbum Hwang]

ㅁ MaaS Version: 3.2.6
ㅁ Interface Used: CLI
ㅁ What happened & Steps to reproduce

When deploying a Windows machine on MaaS, we configured a bonding interface (bond-iscsi) with two physical interfaces (ens3f0, ens6f0) and set the MTU to 9000 to use jumbo packets. In the MaaS machine settings, we set the MTU to 9000 for both the physical interface and the bonding interface and performed deployment.

- used cli command to set mtu on interfaces: maas admin interface update $systemid $interface_id mtu="9000"
- setting result : (The upper part of the screenshot_maas_mtu.png)

However, when I accessed the deployed Windows server and checked the interface settings, I found that the MTU was not set on the physical interfaces but only on the bonding interface. As a result, the bonding interface behaved as if the MTU was the default value of 1500, and the performance of services running on the Windows system was greatly reduced.

- windows system setting: (The lower part of the screenshot_maas_mtu.png)

We solved the problem by manually changing the MTU of the physical interfaces to 9000 on the Windows server.

As far as I know, on Windows servers the physical interface must also be set to the MTU of the same size as the bonding interface. (Unlike Linux systems where setting the MTU only on the bond interface is sufficient)

When setting the MTU for the bonding interface of a Windows server in MaaS, setting the MTU for the physical interface seems to be missing. (Even though the MTU was set on the physical interface in the machine settings before deployment)

I think it's a bug related to setting the MTU on the bonding interface on the Windows server.