When an upgrade is initiated, NSX will deploy and configure a new Edge VM alongside the existing one, which is pretty similar to the NSX Edge redeploy operation. Once the new Edge is ready, the old Edge's vNICs are disconnected, the new NSX Edge's vNICs are connected, and the new Edge sends a gratuitous ARP (GARP) reply to inform other machines about the change in MAC. This process is repeated twice for an HA-enabled Edge.
The impact on the data plane varies depending on the features used, such as HA, dynamic routing, and ECMP. For a standalone Edge, you can enable HA temporarily to minimize the downtime during the upgrade and disable it again upon finishing the upgrade.
The NSX Manager uses the following resource reservations ...
