When the workload in your environment becomes imbalanced, you can move the workload across your objects to rebalance the overall workload. The container for the rebalance action can be a data center or a custom data center, and the objects that are moved are the virtual machines in the recommended list provided by the action.

DRS Must be Enabled on Clusters

Your vCenter Server instance must have a cluster that passes a DRS enabled check for the Rebalance Container action to appear in the Actions drop-down menu.

To get the Rebalance Container action from a custom datacenter or datacenter, and the related alerts, you must have the following:

  • A vCenter Adapter configured with the actions enabled for each vCenter Server instance

  • A vCenter Server instance with at least one cluster that is DRS enabled

If your cluster does not have DRS fully automated, the Rebalance Container action notifies you that one or more clusters under the selected container do not have DRS set to fully automated.

To ensure that the Rebalance Container action is available in your environment, you must add DRS. Then, wait one collection cycle for the Rebalance Container action to appear.

You Must Have Access to All Objects in the Container

If you have access to all objects in a cluster, data center, or custom data center, you can run the Rebalance Container action to move virtual machines to other clusters. When you do not have access to all of the objects in the container, the Rebalance Container action is not available.

How the Rebalance Container Action Works

If one data center in your environment is experiencing a high workload, while another data center in the same environment is experiencing a low workload, you can use the Rebalance Container action to balance the workload across those objects. For example, if the CPU demand on a host in one data center exceeds its available CPU capacity, critical stress occurs on the host. To identify the cause of stress, monitor the CPU demand. Some virtual machines on each host might be experiencing high CPU demand, whereas others might be experiencing a low demand.

The Rebalance Container action moves all affected objects in the recommended list provided by the action to balance the workload. If you do not want to take action on the entire set of objects to resolve the problem with workload or stress, you can use the Move VM action to move an individual object.

Important:

Do not attempt to move virtual machines that are members of a vApp, or else the vApp could become nonfunctional. Instead, add affinity rules for these virtual machines to keep them together so that the Move VM and Rebalance Container actions will ignore them.

When workloads become imbalanced, the following alerts can trigger on data centers and custom data centers. These alerts are disabled by default in the policies.

  • Custom datacenter has unbalanced workload

  • Datacenter has unbalanced workload

When the workloads on hosts in a data center or custom data center differ significantly, click Home > Alerts and verify whether the alert triggered. For example, to verify whether the alert triggered on a custom data center, check the alert named Custom datacenter has unbalanced workload. You can click the alert to view the causes of the alert and identify the source of the imbalance problem on the Summary tab.

To display the recommendations about the objects to move so that you can rebalance the workload, click the Rebalance Container action on the Summary tab. The recommendations indicate that you move one or more virtual machines to another host. When you click OK, a pop-up message provides a link to track the status of the action in Recent Tasks.

The action moves the virtual machines identified in the recommendation to the host machine that has a low workload or stress. You can view the status of the action in the list of recent tasks in Administration > Recent Tasks. You can also use the vSphere Web Client to view the status of the action and the performance for the host.

After the action runs and vRealize Operations Manager performs several collection cycles, you can view the workload on the data center or custom data center to confirm that the workload was rebalanced and that the alert is no longer triggered.

To see how the workload changed on one or more of your hosts, click a host in the navigation tree. Click Analysis > Stress to view the stress score, breakdown, and workload on the host. Then, click Analysis > Capacity Remaining to determine how much capacity remains on the host.

Where You Run the Action

You can run the Rebalance Container action from the Actions menu for a data center or custom data center, or you can provide it as a recommended action on an alert.

For the supported objects and object levels, this action is available in the following locations in vRealize Operations Manager:

  • In the Actions menu on the top toolbar when you click Home.

  • On the toolbar when you click Environment, select an object, click the Details tab, click Views, and select a view of type List.

  • On the toolbar when you click Environment, select an object, click the Environment tab, and select an object in the list view.

  • In the Inventory Explorer list when you click Administration, click Inventory Explorer, click the List tab, and select an object in the list.

  • In configured alert recommendations.

  • In the Object List and Topology Graph dashboard widgets.

Action Recommendations

Review the following information about the hosts and virtual machines to ensure that you are submitting the action for the correct objects.

Option

Description

Virtual Machine

Name of the virtual machine on the host that is experiencing an excessive workload.

Source Cluster

Name of the cluster on which the virtual machine is running

Datastores

Datastore associated with the virtual machine.

Destination Cluster

Cluster where the virtual machine is to be moved. DRS will select the host automatically.

Reason

Describes the action to be taken and the reason why the move is recommended. For example, the recommendation is to move part of the workload on the cluster to another cluster to reduce the imbalance in CPU demand.

Parent vCenter

Identifies the vCenter vCenter Serveradapter associated with the affected cluster.

After you click OK, the next dialog box provides the task ID and a link to the task list.

Table 1. Task ID Dialog Box

Option

Description

Recent Tasks

To view the status of the job and verify that the job finished, click Recent Tasks.

OK

To close the dialog box without further action, click OK.