Placement polices now generally available for Azure VMware Solution
Published date: 16 December, 2021
Placement policies are used to define constraints for running virtual machines in the Azure VMware Solution Software-Defined Data Center (SDDC). These constraints allow the you to decide where and how the virtual machines should run within the SDDC clusters. Placement polices are used to support performance optimisation of virtual machines (VMs) through policy, and help mitigate the impact of maintenance operations to policies within the SDDC cluster.
When you create a placement policy, it creates a vSphere Distributed Resource Scheduler (DRS) rule in the specified vSphere cluster. It also includes additional logic for interoperability with Azure VMware Solution operations.
There are two basic placement policy types now supported:
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Virtual Machine to Virtual Machine: this refers to a policy that is applied to VMs with respect to each other.
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VM-VM Affinity policies instruct DRS to try keeping the specified VMs together on the same host for performance reasons as an example.
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VM-VM Anti-Affinity policies instruct DRS to try keeping the specified VMs apart from each other on separate hosts. It’s useful in scenarios where you may wish to spread your virtual machines across hosts to ensure availability of the applications.
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Virtual Machine to SDDC Host: this refers to a policy applied to selected VMs to either run on, or avoid, selected hosts.
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VM-Host Affinity policies instruct DRS to try running the specified VMs on the hosts defined.
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VM-Host Anti-Affinity policies instruct DRS to try running the specified VMs on hosts other than those defined.
In addition to the above, Azure VMware Solution now lets you restrict vMotions of selected VMs through a policy called “Restrict VM movement”. When enabled, vSphere DRS will not automatically vMotion a virtual machine from a host it currently resides on. This can be useful for workloads that are vMotion sensitive.
For more information on requirements for placement policies in Azure VMware Solution and how to create and apply them, read the documentation.