vSphere 6.7 ICM – Module 9.2 – Configure and manage a vSphere HA cluster

You can easily configure HA cluster by connecting to virtual center web client. Before enabling HA cluster you should refer best practices for HA cluster by VMware .

Best Practices for VMware vSphere® High Availability Clusters

Continuing to the learning of vSphere 6.7 – Install, Configure, and Manage modules, we are going to cover below points in this blog.

Points to Cover: –

Enable HA

Enable DRS

Login to virtual center from web client and select cluster where you want to configure HA.

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Right Click on cluster and go to setting.

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You can notice that HA is in OFF state. Click on edit button to enable HA.2018-07-28 18_58_19-vSphere - Prod_Cluster - vSphere Availability

Enable HA  using sliding button.

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You may also configure ‘failure and responses”,Admission control policy etc as per your requirement and business need and Click OK.

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Now you can see that HA is enable  for your cluster.2018-07-28 18_59_14-vSphere - Prod_Cluster - vSphere Availability

Similar steps we have to perform to enable DRS. Select DRS and click edit button.2018-07-28 19_00_11-vSphere - Prod_Cluster - vSphere DRS

Enable DRS using slide button.2018-07-28 19_00_17-vSphere - Prod_Cluster - vSphere DRS

Click “OK” to save configuration.2018-07-28 19_00_20-vSphere - Prod_Cluster - vSphere DRS

Verify that your HA and DRS is enabled.2018-07-28 19_00_29-vSphere - Prod_Cluster - vSphere DRS


Now we are going to explore about configuring proactive HA and admission control Policy.

Proactive HA responds when a provider has notified its health degradation to vCenter, indicating a partial failure of that host. Virtual machines get migrated to healthy host.

To Configure proactive HA click on cluster and go to configure tab, select vSphere availability and edit proactive HA.

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Enable proactive HA, you have below two option for automation level.

  • Manual- vCenter Server suggests migration recommendations for virtual machines.

  • Automated- Virtual machines are migrated to healthy hosts and degraded hosts are entered into quarantine or maintenance mode depending on the configured Proactive HA automation level.

Select automation level as per your requirement.

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Click save.2018-07-28 19_07_50-vSphere - Prod_Cluster - vSphere Availability

Now we will configure admissions control policy. Admission control specify whether virtual machines can be started if they violate availability constraints. The cluster reserves resources so that failover can occur for all running virtual machines on the specified number of hosts.

Click edit for vSphere HA

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Here you have option  to define host failure cluster can tolerates and define following options.



Cluster resource percentage

Specify a percentage of the cluster’s CPU and memory resources to reserve as spare capacity to support failovers.

Slot Policy (powered-on VMs)

Select a slot size policy that covers all powered on VMs or is a fixed size. You can also calculate how many VMs require multiple slots.

Dedicated failover hosts

Select hosts to use for failover actions. Failovers can still occur on other hosts in the cluster if a default failover host does not have enough resources.


Select this option to disable admission control and allow virtual machine power ons that violate availability constraints.

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You can set the percentage for the Performance degradation VMs tolerate.This setting determines what percentage of performance degradation the VMs in the cluster are allowed to tolerate during a failure.

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Click ok to save configuration2018-07-28 19_08_33-vSphere - Prod_Cluster - vSphere Availability


That’s all from this topic.Refer to next topics to explore more.

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