3.1a2 cloud service and deployment models

Hybrid cloud risks

Config mismatch between environments, inconsistent authentication, hard-to-correlate logs, data crossing the public internet, unclear boundaries.

Third-party vendors (cloud)

Non-CSP suppliers in your cloud stack, e.g. a third-party firewall in front of your app. Must be covered by risk management, IR plans, and monitoring.

Vendor risk management policy

Formal policy for assessing, approving, and monitoring the security of third-party suppliers.

Service level agreement (SLA)

Agreement setting performance, availability, and support expectations between a provider and a customer.

Data in transit (cloud)

Data moving between providers or between on-prem and cloud traverses the public internet and must be encrypted.

Infrastructure as code (IaC)

Managing and provisioning infrastructure using machine-readable definition files instead of manual configuration. Written in YAML, JSON, or HCL.

IaC benefits

Repeatable and consistent builds, version control, easy modification, portable across providers.

IaC risk

A flaw in the definition file is replicated to every system it builds.

Serverless architecture

Cloud model where the provider manages all infrastructure and the app is built from individual functions; no OS for the customer to manage.

Stateless compute container

Short-lived runtime that executes a serverless function and retains no data between executions.

Ephemeral (serverless)

The container may exist only for the duration of a single event or trigger, then be destroyed.

Serverless security focus

OS and infrastructure security belong to the provider; the customer secures the function code, its permissions, and the clients calling it.

Monolithic architecture

One large application containing all functions: UI, business logic, data input/output. Large codebase, difficult change control.

Microservices

Application built as a collection of small independent services, each with a single responsibility and a defined interface.

API (Application Programming Interface)

Defined interface letting software components communicate; the "glue" connecting microservices.

API gateway

Entry point that receives client requests and routes them to the appropriate microservice.

Microservices benefits

Scalability (scale only the busy service), resilience (one outage is contained), security scoped per service.

Microservices risk

Integration problems: components work alone but reveal faults that are hard to isolate once combined.