A VM-Host affinity policy describes a relationship between a category of VMs and a category of hosts.
VM-Host affinity policies can be useful when host-based licensing requires VMs that are running certain applications to be placed on hosts that are licensed to run those applications. They can also be useful when virtual machines with workload-specific configurations require placement on hosts that have certain characteristics.
A VM-Host affinity policy establishes an affinity relationship between a category of virtual machines and a category of hosts. After the policy is created, the placement engine in your SDDC deploys VMs in the category covered by the policy on hosts in the category covered by the policy. You can use existing tags and categories or create new ones specific to your needs. See vSphere Tags and Attributes for more about creating and using tags.
To prevent a VM-Host affinity policy from blocking the upgrade of a host or cluster, VM-Host affinity policies are constrained in several ways.
A policy cannot force a host to enter maintenance mode.
A policy cannot prevent a host configured for HA from executing a failover. VMs with an 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 host affinity policy specifies a resource reservation that no host can meet, it is powered on on any available host.
These constraints are lifted as soon as a compliant host becomes available.
This operation is restricted to users who have the CloudAdmin role.
- Create a category and tag for VMs that you want to include in a VM-host affinity policy.
Pick a category name that describes common characteristics, such as license requirements, of VMs you plan to tag as members of that category.
- Create a category and tag for hosts that you want to include in a VM-host affinity policy.
Pick a category name that describes common characteristics, such as installed license types, of hosts you plan to tag as members of that category.
- Tag the VMs and hosts that you want to include in a VM-host affinity policy.
- Create a VM-Host affinity policy.
- In your SDDC, click OPEN VCENTER.
- From the vSphere Client Home, click .
- Click Add to open the New Compute Policy Wizard.
- Fill in the policy Name and Description, then use the VM tag and Host tag drop-down controls to choose the VM category and Host category to which the policy applies.
The policy Name must be unique within your SDDC. Unless you have multiple VM tags associated with a category, the wizard fills in the VM tag after you select the tag category.
- Click Create to create the policy.
- (Optional) To delete a compute policy, open the vSphere Web Client, click to show each policy as a card. Click DELETE to delete a policy.