Configuration of vSphere 7 DRS Affinity and Anti-affinity rules

Posted on June 8, 2023

VMware Distributed Resource Scheduler (DRS) in vSphere 7 allows you to configure affinity and anti-affinity rules to control the placement of virtual machines (VMs) on hosts in a cluster. These rules help you ensure that certain VMs are kept together on the same host (affinity) or kept apart from each other on different hosts (anti-affinity) based on your specific requirements.

Here’s a guide on how to configure vSphere 7 DRS affinity and anti-affinity rules:

Prerequisites:

  1. Ensure that you have a vSphere cluster with DRS enabled.
  2. You must have the necessary permissions to configure DRS rules.

Steps:

1. Accessing the DRS Cluster:

  • Log in to the vSphere Client.
  • Navigate to the cluster for which you want to configure DRS rules.
  • Click on the “Configure” tab.

2. Enabling DRS:

  • Make sure that DRS is enabled for the cluster.
    • Under “Services,” ensure that “Distributed Resource Scheduler” is enabled.

3. Creating an Affinity or Anti-affinity Rule:

  • In the “Configure” tab, under “Services,” select “Distributed Resource Scheduler.”
  • Click on the “Rules” tab.
  • Click on the “Add Rule” button.

4. Configure Rule Type:

  • Choose either “Should run on hosts in group” (affinity) or “Should not run on hosts in group” (anti-affinity).
  • Provide a meaningful name for the rule.

5. Specify VMs or Hosts:

  • Add VMs or hosts to the rule by dragging and dropping them from the inventory to the rule configuration.
  • For affinity, VMs added to the same rule will prefer to run on the same host.
  • For anti-affinity, VMs added to the same rule will be kept apart on different hosts.

6. Configure Rule Violation:

  • Choose whether the rule should be enforced immediately or allow violations.
  • If you choose to allow violations, DRS will attempt to satisfy the rule but may violate it if necessary.

7. Applying and Reviewing:

  • Click “Add” to apply the rule.
  • Review the list of rules to ensure they are configured correctly.

8. Monitoring DRS:

  • Go to the “Monitor” tab to observe the DRS behavior and any violations of the rules.

Notes:

  • Automation: You can also use PowerCLI or other automation tools to script the creation and management of DRS rules.
  • Advanced Options: DRS provides advanced options for rule configurations, such as specifying affinity or anti-affinity at the VM-VM, VM-Host, or Cluster-Host levels.

Always ensure that you thoroughly test any rules in a non-production environment to understand their impact before applying them to critical workloads.