Migrating or Adding ESXi hosts to a vCenter fails with license capacity errors in vSphere 8

Products

• VMware vCenter Server

Issue/Introduction

When attempting to migrate or add an ESXi host to a vCenter Server 8.x, the Add Host wizard fails during the license validation step. The operation returns an error indicating that license capacity is insufficient, even if the host being added currently shows zero license usage in the pre-check.

In the vSphere Client, you may observe the following error: 

The license capacity is insufficient

Additionally, you may see a validation warning:

The license usage of some assets is measured in units different than the capacity of the selected license. Cannot calculate the license usage before the license is assigned.

Environment

 VMware vCenter Server 8.x , VMware vSphere ESXi 8.x

 

Cause

The  vCenter is in a non-compliant licensing state. vCenter Server actively enforces license capacity limits during host addition operations. If a primary license key in the destination inventory is already over-allocated (for example, usage of 8 CPUs on a 6-CPU capacity license), the license service blocks the addition of any new assets to that pool until the deficit is resolved.

Resolution

To resolve this issue, you must bring the  vCenter back into licensing compliance before completing the host migration.

1. Identify the Over-allocated License

1. Log in to the destination vSphere Client.

2. Navigate to Administration > Licensing > Licenses.

3. Select the Assets tab and click Hosts.

4. Locate the license key where the Usage exceeds the Capacity.

2. Reassign Assets to Resolve the Deficit

1. Identify ESXi hosts currently consuming the over-allocated license.

2. Select one or more hosts and click Assign License.

3. Reassign these hosts to a license key with available capacity (such as a vSphere 8 Enterprise Plus Subscription license or an unassigned perpetual key).

4. Verify that the original license usage now matches or is less than its capacity (e.g., Usage 6 / Capacity 6).

3. Complete the Host Migration

1. Restart the Add Host wizard in the centralized vCenter.

2. When prompted at the License Assignment step, select a license key with sufficient available capacity.

               Note: Subscription keys are recommended for higher core/CPU headroom.

     c.  Complete the remaining steps of the wizard to successfully add the host.

Additional Information

• Core Requirements: For environments utilizing the vSphere 8 per-core licensing model, ensure you account for the 16-core minimum requirement per physical CPU socket when calculating required capacity.

• License Management: If you have multiple smaller perpetual keys, you can merge them into a single higher-capacity key via the Broadcom Support Portal using KB.