Upgrade failure with Host faults in EMM dry run or Is host ready to enter maintenance errors in 2-node compute-only clusters.

Products

• VMware SDDC Manager / VCF Installer

Issue/Introduction

SDDC-Manager upgrade workflows will fail for 2 node compute only cluster, if admission control is enabled on the cluster and running VMs are present on the cluster.

1. General upgrade readiness pre-check
2. Commit pre-checks.
3. Upgrade workflow.

If SDDC-Manager = 9.1 and vCenter = 9.1

 

Possible error descriptions:

Is host ready to enter maintenance

Host '[HOSTNAME]' reported an issue which prevents entering maintenance mode: There are insufficient memory resources on standby hosts (if any) to meet the requirements of a given operation.

DRS reported issues that prevent host '[HOSTNAME]' from entering maintenance mode.

If SDDC-Manager = 9.1 and vCenter <= 9.0

Possible error descriptions:

Host faults in EMM dry run

A host faults were found while performing a dry run enter in maintenance mode validation

Environment

VCF 9.1

Running VMs are present on 2 node compute only cluster and admission control is enabled on the cluster

Cause

This is caused by not enough overhead memory reserved in the cluster for a failover event to occur as required by the current admission control settings

Resolution

1. Select disabled for "Define host failover capacity by" under HA admission control setting by following the below steps.
2. Cluster > Configure > vSphere Availability(from left side bar) > Edit > Admission control > Define host failover capacity by > Disabled
3. When pre-checks are run after disabling the setting, it will pass and upgrade will go through fine.
4. Admission control setting can be re-enabled after upgrade is completed as per the requirement.