ESXi hosts reboot during an NSX host upgrade

Products

• VMware NSX

Issue/Introduction

• NSX upgrade
• All ESXi hosts in a cluster reboot during the ESXi host upgrade process
• Running the API GET https://<NSX_MANAGER>/api/v1/upgrade/upgrade-unit-groups shows rebootless_upgrade as false

Group for <Upgrade Group>
[
  {
    "key": "upgrade_mode",
    "value": "maintenance_mode"
  },
  {
    "key": "rebootless_upgrade",  
    "value": "false"              
  },

Environment

VMware NSX
VMware NSX-T Data Center

Cause

By default, NSX upgrade of ESXi hosts do not require a host reboot.
It is possible to configure hosts to reboot during the upgrade process via API.
This is set at the Upgrade Group level and applies to all hosts in that Upgrade Group.
If at anytime in the past a host group was ever configured to have rebootless upgrade set to false, that setting persists and is saved across future upgrades by design.

Resolution

On the NSX UI, go to System -> Upgrade -> Hosts and click Reset

Alternatively change only this setting via API update

1. Get the configuration for the Upgrade Group
   GET https://<NSX_MANAGER>/api/v1/upgrade/upgrade-unit-groups/<group id>
2. In the API Body captured above, edit the extended_configuration value by updating {"key" : "rebootless_upgrade", "value" : "true"}.
3. Update the Upgrade Group
   PUT https://<NSX_MANAGER>/api/v1/upgrade/upgrade-unit-groups/<group id>