Desired VM Size is Unavailable

Select a VM size whose Restrictions value is None for your subscription and region; if no suitable size is available, change the VM’s region and check again.

Find an available size in the Azure portal

1. On Create a virtual machine → Basics, note the selected Region.
2. Open the Size selector and select See all sizes.
3. Filter or scroll through the list and select a size shown as available.
4. If the sizes are unavailable, return to Basics, choose another Region, and reopen See all sizes.

VM-size availability depends on the combination of subscription, region, and—when selected—availability zone. Azure’s documented resolutions are to choose another available size or deploy in another region or zone.^1^

For an AZ-900 exercise, the exact size or region from the book normally is not essential. Use an available, inexpensive size and delete the VM and its associated resources after the exercise to avoid ongoing charges.

Check availability for your subscription

Because three sizes have already failed, use Azure Cloud Shell to distinguish regional availability from a subscription restriction:

1. In the Azure portal, open Cloud Shell and choose Bash.
2. Replace centralus with the region selected on the VM’s Basics tab.
3. Run:

az vm list-skus \
  --location centralus \
  --resource-type virtualMachines \
  --all \
  --output table

Interpret the Restrictions column:

• None: The size has no listed subscription restriction in that region. Copy its exact Name and select that size in the portal.
• NotAvailableForSubscription: That size cannot be used by the current subscription in the listed region or zone.
• If every practical size is restricted, run the command against another region and create the VM there.

The --all option is important because it includes unavailable SKUs and displays their restrictions; without it, restricted SKUs are omitted.^1^

If the exercise uses Azure CLI, insert a returned unrestricted SKU name into the creation command:

az vm create \
  --resource-group "<resource-group>" \
  --name "az900-vm" \
  --location "centralus" \
  --size "<available-SKU-name>" \
  --image "Ubuntu2204"

If the portal reports a quota problem

Only follow this branch if the unavailable-size message specifically says Insufficient quota, family limit, or similar. That is different from regional capacity or NotAvailableForSubscription.

• On the VM size page, select Request quota if that link appears.
• Alternatively, search the portal for Quotas → Compute, select the relevant region and VM family, then choose New Quota Request.
• A quota request requires Contributor access or another role containing Contributor permissions.^2^

For a temporary learning VM, selecting another unrestricted VM family or region is usually quicker than requesting additional quota. If no suitable SKU is available in any acceptable region, Azure’s documented escalation path is a SKU or support request.^1^

References

1. Resolve errors for SKU not available
2. Increase VM-family vCPU quotas