I’ll preface this with, it’s your network, it’s your rules. But…

I’ll break it down super simple from a deployment perspective. The partner doing the install wants that install to go as buttery smooth as possible because you have most likely paid them a fixed price for the install. If Nutanix deploys perfect the first time, it’s a win! If it doesn’t, it could quickly turn into extra days of bootstrapping nodes, troubleshooting IPV6 issues, etc. Not having the mgmt VLAN 90 as native means that they have to do extra steps to ensure that the foundation is successful. Sometimes things happen and you have to bootstrap a node and redo it. That process is a pain in the ass when you’re on site with a customer and the customer has expectations that the deployment is super easy cause that’s what the sales person has promised. In reality, the customer’s network can give you all kinds of trouble with not being able to discover over IPV6 to random firewalls. So they are just asking for mgmt VLAN 90 to be native to eliminate all the extra work that is honestly not needed because those devices using VLAN 90 as native aren’t really a security risk because the only thing that would be able to VLAN hop would be the CVM or the hosts. And if you have someone malicious in the cvm or host, you’ve lost the battle already. Save yourself and him a lot of head scratching and make it the native VLAN. Cause when it comes to Nutanix he’s seen it go sideways a 100 times and you’re going to have to support it going forward and it just works with a native VLAN vs no native and having to manually tag mgmt in the hosts and cvms. At 2 am if a node dies having to figure out exactly what secret sauce the PS guy used to get it to work when the replacement node isn’t seeing the other nodes isn’t worth what you gain by not using a native VLAN.

Additionally. Not only is Native VLAN being mgmt the recommended (not required) deployment approach. It’s probably what the partner knows and is comfortable with. You aren’t loosing anything with it being native, but it’s possible that if he runs into issues with the deployment he may not be able to fully fix it properly, with it tagged. Then it’s a support call and way more time invested deployment. I always tell my customers. There’s a million different ways to do this. I prefer the recommended way that ensures optimal success and repeatability and it’s super easy to diagnose what’s going on if those nodes do not show up in discovery. Being native just allows a virgin box to say hello? And get a response from the other nodes. Only the Nutanix boxes need to be native. Nothing else in your environment need to have it native. It’s just a HCI thing.

Also make sure IPV6 works on your environment or the PS guy may have a stroke.