Questions
- What is the difference between SaaS, PaaS, and IaaS, and when would you choose each for a project?
- How do you estimate and optimize cloud costs for a multi-service application?
- What are best practices for identity and access management (IAM) in a cloud environment?
- How can you implement secure backups and disaster recovery using cloud-based tools?
- What considerations are there for data residency, sovereignty, and compliance when using cloud services?
- How do you set up a CI/CD pipeline in the cloud, and what tools are commonly used?
- What strategies improve performance and reliability for cloud-based applications (e.g., caching, load balancing, auto-scaling)?
- How can you ensure security for serverless architectures and managed services in the cloud?
- What is a typical cloud security shared responsibility model, and what are common gaps to watch for?
- How do you approach data integration and interoperability when using multiple cloud providers or SaaS tools?
Answers
- SaaS delivers software over the internet managed by the vendor (no infrastructure to manage). PaaS provides a platform to build and deploy applications (vendor manages runtime, middleware, OS), while IaaS gives virtualized computing resources (you manage OS/runtime/app). Choose SaaS for quick, maintenance-free apps; PaaS when you want to develop and deploy apps without managing underlying infrastructure; IaaS when you need control over OS and software stack or require custom environments.
- Track spend by service (compute, storage, data transfer), set budgets/alerts, right-size instances, use reserved/spot/preemptible instances where applicable, implement autoscaling, clean up unused resources, and apply cost governance (tagging, dashboards). Consider cost modeling for multi-region usage and data egress, and use cost-optimization recommendations from cloud providers.
- Follow least privilege, use centralized IAM with MFA, enforce strong password and rotation policies, enable conditional access and identity federation, implement role-based or attribute-based access control, monitor and audit with logs, rotate credentials, and separate duties. Use CI/CD and infrastructure as code to limit manual access and automate provisioning.
- Use cloud-native backup services or tooling, implement regular automated backups with point-in-time recovery, test restores regularly, store backups in separate regions or zones, use encryption in transit and at rest, define RPO/RTO targets, and document disaster recovery runbooks. Consider cross-region replication and immutable backups where appropriate.
- Understand where data resides and how it moves, check vendor data processing agreements, ensure geographic data storage complies with regulations, use encryption for data at rest and in transit, implement data minimization, and consider legal jurisdiction for data access requests. Use data-transfer and residency controls offered by providers and keep audit logs.
- Choose a cloud CI/CD platform (e.g., Git-based pipelines, build/test runners, artifact registries). Define workflows for build, test, security/scanning, and deployment to environments (dev/staging/prod). Use infrastructure-as-code for deployments, integrate security checks (SAST/DAST), and implement gated promotions and rollback plans.
- Use autoscaling to match demand, implement load balancing across regions, cache data close to users (CDN, in-memory caches), optimize database performance (read replicas, partitioning), design for fault tolerance and retries, monitor latency, and implement circuit breakers. Use asynchronous messaging where appropriate to decouple components.
- For serverless, apply fine-grained IAM and resource policies, limit function permissions to only what’s needed, encrypt environment variables, monitor for cold starts and cost, and implement secure secret management. Use secure APIs, audit logs, and regularly review permissions. Ensure third-party services and dependencies are trusted and kept up to date.
- The shared responsibility model delineates cloud provider duties (infrastructure, physical security, core services) and customer duties (data, access control, application security). Common gaps include misconfigured storage permissions, excessive IAM privileges, unpatched dependencies, insufficient network controls, and inadequate monitoring. Regular audits, automation, and security baselines help close gaps.
- Use data integration tools and APIs that support common data formats, authentication standards, and event-driven architectures. Favor standardized connectors, implement data governance and lineage, manage credentials securely, and plan for data mapping between SaaS apps and cloud data stores. Consider multi-cloud integration platforms or middleware to avoid vendor lock-in and maintain interoperability.