Short definitions for cloud service models, automation, resilience, and operations terms.
| Term | Definition |
|---|---|
| IaaS | Infrastructure as a service; virtualized compute, storage, and networking with customer responsibility above the infrastructure layer |
| PaaS | Platform as a service; managed application runtime or service platform |
| SaaS | Software as a service; provider-operated application consumed by users or organizations |
| IaC | Infrastructure as code; versioned, repeatable infrastructure definitions |
| RTO | Recovery time objective; maximum acceptable service-outage interval |
| RPO | Recovery point objective; maximum acceptable data-loss interval |
| Shared responsibility | Allocation of security and operating responsibilities between provider and customer |
| Drift | Difference between the intended configuration and the running state |
| Failover | Moving service or traffic to another environment after failure |
| Failback | Returning service to the original environment after recovery |