SaaS SaaS Architecture and Infrastructure 2

Question 1

What is a SLA (Service Level Agreement) uptime of 99.9% equivalent to in downtime per year?

Accepted Answer

About 8.7 hours per year

Answer

99.9% uptime ('three nines') allows approximately 8.76 hours of downtime per year; many enterprise SaaS products target 99.99% ('four nines'), which allows only ~52 minutes per year.

Question 2

What is blue-green deployment in SaaS engineering?

Accepted Answer

Running two identical production environments where traffic is switched instantly to the new version, enabling zero-downtime deployments

Answer

Blue-green deployment maintains two identical environments; the new version is deployed to the inactive environment and traffic is switched instantly, enabling instant rollback if issues arise.

Question 3

What is infrastructure as code (IaC) and how does it benefit SaaS operations?

Accepted Answer

Defining and provisioning infrastructure using code (Terraform, CloudFormation), enabling version control, reproducibility, and automation

Answer

IaC tools like Terraform allow SaaS teams to define infrastructure declaratively in code, enabling version-controlled, auditable, and reproducible environment provisioning.

Question 4

What is auto-scaling in cloud-based SaaS infrastructure?

Accepted Answer

Dynamically adding or removing compute resources based on real-time demand metrics

Answer

Auto-scaling monitors metrics like CPU usage or request rate and automatically adds or removes instances to maintain performance during traffic spikes while minimizing cost during lulls.

Question 5

What is a circuit breaker pattern in distributed SaaS systems?

Accepted Answer

A resilience pattern that detects when a downstream service is failing and stops sending requests to it, allowing it to recover

Answer

The circuit breaker pattern prevents cascading failures by detecting repeated errors from a downstream service and temporarily stopping requests to it, returning fast-fail responses while it recovers.

SaaS Practice Test

SaaS Practice Test

SaaS SaaS Architecture and Infrastructure 2