Cloud Computing Fundamentals
Domain 1 - Cloud Computing Fundamentals. This domain tests whether you can explain the cloud delivery model precisely: service models, the shared responsibility boundary, regions and availability zones, and the operating model that makes infrastructure automatable. Expect scenario questions that ask who owns a control or which model fits a workload.
Service and responsibility models
- IaaS exposes compute, network, and storage primitives; you patch the OS and runtime.
- PaaS manages the runtime and often the database engine; you manage configuration, identity, and data.
- SaaS delivers the application; you manage users, data, and sharing settings. The provider is always responsible for security of the cloud - physical facilities, hypervisors, and the internals of managed services. The customer is always responsible for security in the cloud - identities, access policy, data classification, and configuration. The boundary moves with the service model but never disappears.
Regions, zones, and resilience
A region is a geographic area; an availability zone is an isolated failure domain inside it. Multi-AZ designs tolerate a datacenter failure. Multi-region designs add latency and disaster-recovery options but require data replication, routing, and failover automation - they are not automatic.
The cloud operating model
HashiCorp's framing: a central platform team publishes golden workflows and guardrails; product teams self-serve through APIs and IaC; policy is codified. Infrastructure is declarative and versioned, not hand-built.
Worked example
A team moves PostgreSQL from VMs to a managed database. On VMs, the team owns OS patching, database engine patching, backup jobs, IAM, and security-group rules. On the managed service, the provider owns host and engine patching and physical durability; the team still owns database users, network exposure, backup retention configuration, and data classification. The correct answer to 'who owns patching?' is therefore 'the provider for the engine, the customer for access and configuration' - responsibility shifted, it did not vanish.
Traps
- Claiming the provider secures customer data in SaaS; customer identity and sharing controls remain customer-owned.
- Assuming multi-region means automatic failover.
- Confusing elasticity (automatic matching of capacity to demand) with scalability (ability to grow).
- Treating IaC as imperative scripting; Terraform declares desired state and computes a diff.