NSX Manager Precheck Failure Due to Even Number of Nodes Detected. Please attach/delete one node to proceed with upgrade

Products

• VMware NSX

Issue/Introduction

• Precheck execution on the NSX Manager is unsuccessful, with an error "Upgrade is not allowed for a cluster having even number of nodes. Please attach/delete one node to proceed with upgrade"

Environment

VMware NSX

Cause

• This is an expected behavior, NSX Manager does not support upgrades when the cluster has an even number of nodes.

• If the NSX cluster is deployed with 2 nodes, the precheck validation will fail, as a third node is required for upgrade support.

• To proceed with the upgrade, the cluster must have either 1 or 3 nodes (an odd number).

Resolution

•  As per best practices, NSX Manager should be deployed as a 3-node cluster to ensure redundancy for both the management and control planes.

         Workaround: To proceed with the upgrade we can follow either of the options.

Option1:

Detach one node to temporarily run as a standalone node for the upgrade

SSH to NSX manager as admin.
get cluster status <--- to check the cluster health make sure the cluster is stable.

Members:
UUID                                                              FQDN                                   IP               STATUS
 824################07b                                            mgr01                                 192.#.#.1        UP
 155################537                                            mgr02                                 192.#.#.2        UP

Detach mgr02:
mgr01> detach node <uuid of mrg02>
Node has been detached. Detached node must be deleted permanently.

Option2:

Or, deploy a new node to complete the 3-node cluster. Refer Deploy NSX Manager Nodes to Form a Cluster from the UI