When a guest is migrated to a new system, there are some cases where you want it to be placed with a specific guest, or want it not to be placed with a specific guest. Perhaps you have multiple guests that make up the parts of a three-tiered application, and you want to keep them together. Or perhaps you have two guests that are different nodes of an HA cluster, and putting them together would defeat the purpose.
Starting in Ops Center 12.3.1, you can use affinity tags to establish preferences for where guests go. You do this by selecting the guest, clicking Edit Tags, and using these tags:
affinityTags — This tag identifies the guest for other guests' affinities and disaffinities.
affinities — Which other guests the current guest should be placed with.
disaffinities — Which other guests the current guest should not be placed with.
For example, let's say that you have three groups of guests - A, B, and C - and you want to keep each group together. Here are the tags that you could assign to the guests in Group A:
affinityTags — Group A
affinities — Group A
disaffinities — Group B, Group C
There's more information about affinities and disaffinities in the Virtualization Reference document.