How is the OIC Cloud Service Physically Deployed?

When a customer creates a new Oracle Integration Cloud Service within an OCI region, is that service deployed in a way that ensures fault-tolerance and high availability within the region? For example, Ashburn has three availability domains. If a customer deploys an OIC instance in Ashburn, and 1 or 2 of those Ashburn availability domains experience an outage, will the OIC instance automatically survive and be available within one of the remaining availability domains in Ashburn? Is the service also deployed across multiple fault-domains within multiple availability domains?