---
title: "Configuring NIOS Virtual Appliances as Grid Masters"
canonical: "https://docs.infoblox.com/space/NKHOIG/35915776/Configuring%20NIOS%20Virtual%20Appliances%20as%20Grid%20Masters"
format: markdown
---
> Macro (include)

> ⚠️ **Note**
> ⚠️ 
> ⚠️ For vNIOS for KVM Hypervisor and KVM based OpenStack, the VPN MTU (maximum transmission unit) size for any virtual appliance using OpenStack must be 1500 bytes to avoid any inconsistencies in the instance. For more information about MTU, see the *Setting the MTU for VPN Tunnels* section in the *[Infoblox NIOS Documentation](https://docs.infoblox.com/)*<span style="color: #000000">.</span>