The vSphere Client lists an alert stating, "Insufficient HA failover resources" or "Insufficient resources to satisfy vSphere HA failover level on cluster <Cluster_name> in <Datacenter_name>"

Products

• VMware vCenter Server

Issue/Introduction

After vSphere HA has been enabled on a cluster, the following alerts are seen in the vSphere Client:

• Insufficient HA failover resources
• Insufficient resources to satisfy vSphere HA failover level on cluster <Cluster_name> in <Datacenter_name>

 

Environment

• vSphere 7.x
• vSphere 8.x

Cause

"Insufficient vSphere HA failover resources" alerts can be caused by the following:

• Admission Control configuration within vSphere HA
• Resource reservations on VMs in the cluster

For example, if a host in a two host cluster becomes unavailable, vSphere HA will not be able to satisfy the Admission Control settings on the remaining host.  The remaining host also may not be able run all of the VMs in the cluster if those VMs have CPU/memory reservations that exceed the available resources of the remaining host.

Resolution

In order to avoid a scenario where a cluster has insufficient resources to satisfy vSphere HA, determine a host toleration failure amount for the cluster, and plan the environment to have enough hosts available to satisfy the resource demand on the cluster when one or more hosts have failed.

 

Additional Information

To suppress the insufficient resources alerts, Admission Control in vSphere HA can be disabled.  Another option is to add additional hosts to the cluster so sufficient resources can be provided for Admission Control to manage failover operations.