There are multiple types of commitments that AWS offers, some of which like Zonal Standard RIs come bundled with a capacity reservation to ensure access to the underlying machine being covered. See more details here
By default, Archera GRIs are created from Regional Standard RIs or Savings Plans, which don't come with a capacity reservation; however, they can synergize with an existing capacity reservation to provide a billing discount.
In certain circumstances, particularly with machines like GPUs that have low-capacity-availability, Archera supports creating GRIs from Zonal Standard RIs, which do come with a capacity reservation and can give customers the piece of mind that they will always have access to spin up the machine they are committed to. Please note that this is not the default GRI option and you will have to contact us in order to make use of this option.
If you are interested in using Zonal GRIs with a capacity reservation please contact firstname.lastname@example.org to learn more.