A traditional health check typically asserts that an instance is able to access all the resources that it needs to operate properly. A regional health check does the same thing but from the perspective of the region as a whole. It asserts that all the value-added cloud services (that is, resources) used by the system are operating properly within the given region. If any one resource is unavailable, we will failover the entire region, as discussed in the Triggering regional failover recipe.
The health check service is implemented as a REGIONAL API Gateway based service and deployed to each region. We then need to periodically invoke the health check in each region to check that the region is healthy. We could have Route53 ...
