A VM-Host anti-affinity policy describes a relationship between a category of VMs and a category of hosts.
A VM-Host anti-affinity policy can be useful when you want to avoid placing virtual machines that have specific host requirements such as a GPU or other devices, or capabilities such as IOPS control, on hosts that can't support those requirements. After the policy is created, the placement engine in your SDDC avoids deploying VMs covered by the policy on hosts covered by the policy.
To prevent a VM-Host anti-affinity policy from blocking the upgrade of a host or cluster, these policies are constrained in several ways.
- A policy cannot prevent a host from entering maintenance mode.
- A policy cannot prevent a host configured for HA from executing a failover. VMs with an anti-affinity for the failed host can be migrated to any available host in the cluster.
- A policy cannot prevent a VM from powering-on. If a VM subject to a VM-Host anti-affinity policy specifies a resource reservation that no host can meet, it is powered on on any available host.
Prerequisites
This operation is restricted to users who have the CloudAdmin role.