## TL;DR
The reservation is a capacity commitment, and the region does not have the requested SKU available right now. Buy the reservation for a different SKU, a different region, or a shared scope, and confirm capacity before committing.

```text
reservation order failed: not enough capacity for the requested SKU in this region
```

## Use this when
- A reservation purchase fails with this capacity error.
- The SKU is a newer or constrained family in that region.
- You need the reservation active by a deadline.

## Not for this skill when
- The purchase succeeds but the discount does not apply. That is a scope problem.
- An exchange fails. That is an eligibility problem.

## Steps
1. Check regional capacity for the SKU: try the VM size availability in the target region. Verify: you know which SKUs actually have headroom there.
2. Pick the nearest alternative: same family in a nearby region, or a neighboring SKU size in the same region. Verify: the alternative meets the workload's needs.
3. Place the reservation for the available SKU or region. Verify: the order completes.
4. Scope the reservation (shared, subscription, or resource group) to match where the usage will run. Verify: the scope covers the intended subscriptions.
5. Confirm the discount applies in Cost Management within a day. Verify: usage shows the reservation discount.

### Deadline variant
If the reservation must be live by a date, buy the available alternative now and plan a later exchange to the preferred SKU. Verify: the exchange rules allow the future swap.

Compatibility: Azure Reservations for VMs and other eligible services.

## Why it happens
Reservations reserve real capacity, not just a price. Regions run out of specific SKUs, especially new families and GPU sizes, and the purchase API refuses rather than selling a commitment it cannot honor.

## Edge cases / pitfalls
- Capacity changes over time; a SKU unavailable today may be available next week. Retry before redesigning.
- Buying in the wrong region to dodge the error discounts the wrong usage. Scope matters more than speed.
- Shared scope lets the reservation float to subscriptions where the SKU exists.
- Track reservation utilization; a capacity-forced SKU choice that goes unused still bills.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_13BSBRb7NGuLdtgE0daRgg