--- tags: - cloud - l1 - flashcard-deck - cloud-deep-dive --- [Portal](../../../../library/portal/index.md) | **Level:** [L1: Foundations](../../../../library/portal/levels.md) | **Topics:** [Cloud Deep Dive](../../../../library/portal/topics.md) | **Domain:** Cloud id category difficulty tags question answer source_path cloud/10b5c34aa51f cloud medium cloud, architecture, cost True or False? Auto Scaling is about adding resources (such as instances) and not about removing resource False. Auto scaling adjusts capacity and this can mean removing some resources based on usage and performances.\n\nRemember: the three main cloud providers: AWS (market leader, most services), Azure (strong enterprise/Windows integration), GCP (strong data/ML, Kubernetes origin). Learn one deeply, then map to others.\n\nGotcha: cloud costs can spiral quickly. Set up billing alerts, use cost allocation tags, and right-size resources from day one. 'It's just a small instance' adds up across 50 services. projects/knowledge/interview/cloud/011-true-or-false-auto-scaling-is-about-adding-resourc.txt cloud/17cd208876af cloud hard cloud, managed-services How to secure instances in the cloud? * Instance should have minimal permissions needed. You don't want an instance-level incident to become an account-level incident\n * Instances should be accessed through load balancers or bastion hosts. In other words, they should be off the internet (in a private subnet behind a NAT). \n * Using latest OS images with your instances (or at least apply latest patches)\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/012-how-to-secure-instances-in-the-cloud.txt cloud/19138b991f84 cloud medium cloud, cost, managed-services What is Serverless Computing? The main idea behind serverless computing is that you don't need to manage the creation and configuration of server. All you need to focus on is splitting your app into multiple functions which will be triggered by some actions.\n\nIt's important to note that:\n\n* Serverless Computing is still using servers. So saying there are no servers in serverless computing is completely wrong\n* Serverless Computing allows you to have a different paying model. You basically pay only when your functions are running and not when the VM or containers are running as in other payment models projects/knowledge/interview/cloud/008-what-is-serverless-computing.txt cloud/2cb67ea76fd1 cloud easy cloud, architecture What is the difference between horizontal scaling and vertical scaling? "[AWS Docs](https://wa.aws.amazon.com/wellarchitected/2020-07-02T19-33-23/wat.concept.horizontal-scaling.en.html):\n\nA ""horizontally scalable"" system is one that can increase capacity by adding more computers to the system. This is in contrast to a ""vertically scalable"" system, which is constrained to running its processes on only one computer; in such systems the only way to increase performance is to add more resources into one computer in the form of faster (or more) CPUs, memory or storage.\n\nHorizontally scalable systems are oftentimes able to outperform vertically scalable systems by enabling parallel execution of workloads and distributing those across many different computers." projects/knowledge/interview/cloud/010-what-is-the-difference-between-horizontal-scaling-.txt cloud/312862b94815 cloud easy cloud, economics, basics True or False? Cloud computing is a consumption-based model. TRUE.\n\nConsumption-based model means:\n- Pay for what you use\n- No upfront capital expense\n- Scale up/down as needed\n- Metered billing (per hour, GB, request)\n\nExamples:\n- EC2: Pay per hour/second of runtime\n- S3: Pay per GB stored + requests\n- Lambda: Pay per invocation + duration\n\nBenefits:\n- No overprovisioning waste\n- Convert CapEx to OpEx\n- Match cost to actual usage\n- Easy to experiment\n\nContrast with traditional:\n- Buy hardware upfront\n- Pay for capacity not usage\n- Difficult to scale\n\nKey cloud economics principle: Pay-as-you-go.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/013-true-or-false-cloud-computing-is-a-consumption-bas.txt cloud/35d69578fc7e cloud easy cloud, cost What is auto scaling? "AWS definition: ""AWS Auto Scaling monitors your applications and automatically adjusts capacity to maintain steady, predictable performance at the lowest possible cost""\n\nRead more about auto scaling [here](https://aws.amazon.com/autoscaling)\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity)." projects/knowledge/interview/cloud/009-what-is-auto-scaling.txt cloud/4de4b7a832bb cloud medium cloud, managed-services, hybrid Explain each of the following and give an example: * IAAS - Users have control over complete Operating System and don't need to worry about the physical resources, which is managed by Cloud Service Provider.\n * PAAS - Cloud Service Provider takes care of Operating System, Middlewares and users only need to focus on our Data and Application.\n * SAAS - A cloud based method to provide software to users, software logics running on cloud, can be run on-premises or managed by Cloud Service Provider.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/005-explain-each-of-the-following-and-give-an-example-.txt cloud/65fe29f41810 cloud easy cloud, hybrid What types of clouds (or cloud deployments) are there? * Public - Cloud services sharing computing resources among multiple customers\n * Private - Cloud services having computing resources limited to specific customer or organization, managed by third party or organizations itself\n * Hybrid - Combination of public and private clouds\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/006-what-types-of-clouds-or-cloud-deployments-are-ther.txt cloud/77b9c46bdfd3 cloud medium cloud, saas, managed-services Is there a difference between managed service and SaaS? Yes, though they overlap:\n\nManaged Service:\n- Cloud provider manages infrastructure\n- You control application/data\n- Examples: RDS, ElastiCache, managed Kubernetes\n- Still requires some configuration\n\nSaaS (Software as a Service):\n- Complete application provided\n- No infrastructure management\n- Just use the software\n- Examples: Salesforce, Office 365, Slack\n\nComparison:\n- Managed Service: Managed infrastructure, your app\n- SaaS: Entire application managed for you\n\nSpectrum of management:\n- IaaS: You manage most (EC2)\n- PaaS: Platform managed (Heroku)\n- Managed Service: Specific service managed (RDS)\n- SaaS: Everything managed (Gmail)\n\nRemember: IaaS = you manage OS up (EC2). PaaS = you manage app + data (Heroku, App Service). SaaS = you manage nothing (Gmail). Think 'pizza analogy': IaaS=kitchen, PaaS=delivery, SaaS=restaurant.\n\nExample: IaaS: AWS EC2, Azure VMs. PaaS: Heroku, Google App Engine. SaaS: Salesforce, Google Workspace. projects/knowledge/interview/cloud/015-is-there-a-difference-between-managed-service-to-s.txt cloud/7d867b0a7948 cloud hard cloud, cost How do you control cloud sprawl? Sprawl is a governance problem, not a technical one:\n\n**IAM discipline**:\n* Least privilege - no blanket admin\n* Service accounts with minimal scope\n* Regular access reviews\n\n**Tagging**:\n* Mandatory tags: owner, cost-center, environment\n* Automated enforcement via policies\n* Reports based on tags\n\n**Budgets and alerts**:\n* Per-team/project budgets\n* Alerts before hitting limits\n* Regular cost reviews\n\n**Automation**:\n* Infrastructure as Code only - no console clicking\n* Automated cleanup of unused resources\n* Scheduled shutdown for non-prod\n\nPolicy docs nobody reads don't work. Automation and enforcement do.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/018-how-do-you-control-cloud-sprawl.txt cloud/85c98c68574c cloud hard cloud, architecture, migration Can we replace any type of computing on servers with cloud computing? Not always - some workloads are better on-premises.\n\nCloud-suitable:\n- Variable workloads\n- Rapid scaling needs\n- Global distribution\n- New projects/startups\n- Disaster recovery\n\nBetter on-premises:\n- Consistent high utilization\n- Strict data sovereignty\n- Ultra-low latency requirements\n- Specialized hardware (some HPC)\n- Regulatory restrictions\n- Large predictable workloads (cost)\n\nHybrid considerations:\n- Legacy applications\n- Integration requirements\n- Compliance needs\n- Cost optimization\n\nFactors to evaluate:\n- Total cost of ownership\n- Performance requirements\n- Security and compliance\n- Operational expertise\n- Vendor lock-in risk\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/014-can-we-replace-any-type-of-computing-on-servers-wi.txt cloud/977702d3a2fd cloud hard cloud, cost, architecture, regions What are common cloud vs on-prem performance myths? Cloud isn't automatically faster. Reality:\n\n**Network latency**: Cloud network can have higher latency than local datacenter. Multi-region adds more.\n\n**Storage class matters**: Default EBS isn't SAN performance. Provisioned IOPS costs money.\n\n**Noisy neighbors**: Shared infrastructure means variable performance. Dedicated hosts exist but cost more.\n\n**Right-sizing**: Oversized VMs waste money, undersized ones underperform. Cloud makes it easy to test.\n\n**Truth**: Cloud buys flexibility and scale, not raw performance. On-prem can be faster for specific workloads, but harder to scale.\n\nDesign for the tradeoffs you actually have.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/019-cloud-vs-on-prem-performance-myths.txt cloud/b7e89e891048 cloud hard cloud, architecture Lift-and-shift vs re-architecture - when to use each? **Lift-and-shift** (rehosting):\n* Move VMs/apps as-is to cloud\n* Buys speed - migrate fast\n* Lower initial effort\n* Technical debt comes later\n* Good for: Datacenter exit deadlines, initial migration\n\n**Re-architecture** (refactoring):\n* Redesign for cloud-native patterns\n* Long-term stability and cost control\n* Higher initial investment\n* Better scalability, resilience\n* Good for: Core business apps, long-term cloud strategy\n\n**Reality**: Most migrations are hybrid - lift critical apps, refactor over time. Don't let perfect be enemy of done, but have a modernization roadmap.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/017-lift-and-shift-vs-re-architecture.txt cloud/c2638c931e6f cloud easy cloud, managed-services What types of Cloud Computing services are there? IAAS - Infrastructure as a Service\nPAAS - Platform as a Service\nSAAS - Software as a Service\n\nRemember: the three main cloud providers: AWS (market leader, most services), Azure (strong enterprise/Windows integration), GCP (strong data/ML, Kubernetes origin). Learn one deeply, then map to others.\n\nGotcha: cloud costs can spiral quickly. Set up billing alerts, use cost allocation tags, and right-size resources from day one. 'It's just a small instance' adds up across 50 services. projects/knowledge/interview/cloud/004-what-types-of-cloud-computing-services-are-there.txt cloud/c96ecf418a4e cloud hard cloud, architecture How do you design for failure in cloud? Assume everything fails. Design accordingly:\n\n**Stateless services**: Don't store session state locally. Use external stores (Redis, database).\n\n**Redundancy**: Multi-AZ at minimum. Multi-region for critical services. No single points of failure.\n\n**Health checks**: Load balancers detect and route around failures automatically.\n\n**Automation for rebuilds**: Can you recreate from scratch? Infrastructure as Code, immutable images, automated deployments.\n\n**Graceful degradation**: Services should fail partially, not completely. Circuit breakers, timeouts, retries with backoff.\n\n**Testing**: Chaos engineering - intentionally break things to verify resilience.\n\nManual recovery doesn't scale. If a human must intervene for every failure, you're doing it wrong. projects/knowledge/interview/cloud/020-how-do-you-design-for-failure-in-cloud.txt cloud/ceb9438d2ac2 cloud easy cloud, cost What are the advantages of cloud computing? Mention at least 3 advantages * Pay as you go: you are paying only for what you are using. No upfront payments and payment stops when resources are no longer used.\n* Scalable: resources are scaled down or up based on demand\n* High availability: resources and applications provide seamless experience, even when some services are down\n* Disaster recovery\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/003-what-are-the-advantages-of-cloud-computing-mention.txt cloud/ea9abebc2a5a cloud easy cloud, managed-services, cost, hybrid What is Cloud Computing? What is a Cloud Provider? Cloud computing refers to the delivery of on-demand computing services \nover the internet on a pay-as-you-go basis.\n\nIn simple words, Cloud computing is a service that lets you use any computing\nservice such as a server, storage, networking, databases, and intelligence, \nright through your browser without owning anything. You can do anything you \ncan think of unless it doesn't require you to stay close to your hardware.\n\nCloud service providers are companies that establish public clouds, manage private clouds, or offer on-demand cloud computing components (also known as cloud computing services) like Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service(SaaS). Cloud services can reduce business process costs when compared to on-premise IT. projects/knowledge/interview/cloud/002-what-is-cloud-computing-what-is-a-cloud-provider.txt cloud/edf70210f7b5 cloud medium cloud, cost, hybrid What are the differences between Cloud Providers and On-Premise solution? In cloud providers, someone else owns and manages the hardware, hire the relevant infrastructure teams and pays for real-estate (for both hardware and people). You can focus on your business.\n\nIn On-Premise solution, it's quite the opposite. You need to take care of hardware, infrastructure teams and pay for everything which can be quite expensive. On the other hand it's tailored to your needs.\n\nRemember: cloud architecture patterns: scalability (horizontal > vertical), resilience (multi-AZ, multi-region), security (least privilege, encryption everywhere), and cost optimization (right-sizing, reserved capacity). projects/knowledge/interview/cloud/007-what-are-the-differences-between-cloud-providers-a.txt --- ## Wiki Navigation ### Related Content - [AWS CloudWatch](../../../../library/topics/aws-cloudwatch/index.md) (Topic Pack, L2) — Cloud Deep Dive - AWS Devops Flashcards *(CLI)* (flashcard_deck, L1) — Cloud Deep Dive - [AWS EC2](../../../../library/topics/aws-ec2/index.md) (Topic Pack, L1) — Cloud Deep Dive - [AWS ECS](../../../../library/topics/aws-ecs/index.md) (Topic Pack, L2) — Cloud Deep Dive - AWS General Flashcards *(CLI)* (flashcard_deck, L1) — Cloud Deep Dive - [AWS IAM](../../../../library/topics/aws-iam/index.md) (Topic Pack, L1) — Cloud Deep Dive - [AWS Lambda](../../../../library/topics/aws-lambda/index.md) (Topic Pack, L2) — Cloud Deep Dive - [AWS Networking](../../../../library/topics/aws-networking/index.md) (Topic Pack, L1) — Cloud Deep Dive - [AWS Route 53](../../../../library/topics/aws-route53/index.md) (Topic Pack, L2) — Cloud Deep Dive - [AWS S3 Deep Dive](../../../../library/topics/aws-s3-deep-dive/index.md) (Topic Pack, L1) — Cloud Deep Dive