What is the definition of cloud computing?
On-demand delivery of IT resources (compute, storage, databases, networking) via an API-driven model. Resources are provisioned in seconds to minutes, and you pay only for what you use.
What are the three cloud deployment models?
- All-in Cloud – all workloads on a cloud provider like AWS (used by startups/modern enterprises) | 2. On-Premises (Private Cloud) – own data centre, internal virtualisation (strict security/compliance) | 3. Hybrid Cloud – mix of cloud + on-premises connected via high-speed links (legacy + cloud benefits)
What is the difference between Hybrid Cloud and Multi-Cloud?
Hybrid cloud = on-premises + one cloud provider. Multi-cloud = using multiple cloud providers simultaneously.
What are the pros and cons of traditional on-premises IT?
Pros: increased control and customisation. | Cons: high cost, slow scaling (doubling servers can take weeks/months), requires upfront investment in hardware, power, cooling, rack space, and staffing.
What are the 6 benefits of cloud computing (key exam topic)?
- Trade fixed expense (CapEx) for variable expense (OpEx) | 2. Benefit from massive economies of scale | 3. Stop guessing capacity | 4. Increase speed and agility | 5. Stop spending money on running/maintaining data centres | 6. Go global in minutes
Explain ‘Trade fixed expense for variable expense’ in cloud.
In cloud you pay only for what you consume – no upfront capital expenditure on data centres/servers. You pay only when computing resources are consumed.
Explain ‘Benefit from massive economies of scale’.
AWS aggregates usage from hundreds of thousands of customers, driving down pay-as-you-go prices through its massive purchasing power.
Explain ‘Stop guessing capacity’.
Traditional IT forces over-provisioning (wasted resources) or under-provisioning (performance issues). Cloud lets you scale up/down in minutes to access exactly the capacity you need.
Explain ‘Increase speed and agility’.
New IT resources are available in minutes vs. weeks in traditional IT, dramatically reducing the time and cost of experimentation and development.
Explain ‘Go global in minutes’.
You can deploy applications in any AWS Region worldwide with a few clicks, giving end users lower latency and a better experience globally.
What is CapEx vs OpEx in the context of cloud?
CapEx = upfront capital investment in hardware with long depreciation cycles (3-5 years) and over/under-provisioning risk. | OpEx = pay-as-you-go, no upfront cost, expense in the same period as use, right-sized resources.
What factors should you consider for Total Cost of Ownership (TCO)?
Server/hardware costs, data centre facility costs (power, cooling, space), IT staff salaries, licensing fees, security/compliance overhead, and opportunity cost of time spent managing infrastructure.
What are the 5 AWS pricing models?
- On-Demand – pay by hour/second, no commitment | 2. Reserved Instances (1 or 3-year) – up to 72% discount | 3. Spot Instances – bid on unused capacity, up to 90% discount, can be interrupted | 4. Savings Plans – flexible commitment-based pricing | 5. Dedicated Hosts – physical server dedicated to your use
What are the 6 pillars of the AWS Well-Architected Framework?
- Operational Excellence | 2. Security | 3. Reliability | 4. Performance Efficiency | 5. Cost Optimisation | 6. Sustainability
Describe the Operational Excellence pillar.
Run and monitor systems, continuously improve operations. Emphasizing best operational practices.
Describe the Security pillar of the Well-Architected Framework.
Protect information, systems, and assets. Key practices: implement strong identity, enable traceability, apply security at all layers, automate security best practices, protect data in transit and at rest.
Describe the Reliability pillar.
Ensuring fault tolerance, leveraging high availability, disaster recovery plans, and resiliency.
Describe the Performance Efficiency pillar.
Use computing resources efficiently. Key practices: use advanced technologies, go global in minutes, use serverless architectures, experiment more often.
Describe the Cost Optimisation pillar.
Avoid unnecessary costs. Utilizing the right service efficiently to control costs.
Describe the Sustainability pillar.
Focusing on environmentally friendly and sustainable solutions.
What are the 4 cloud design principles (beyond the Well-Architected Framework)?
- Design for failure – assume everything fails; build resiliency (no single point of failure) | 2. Decouple components – loosely coupled architectures (e.g. SQS) reduce blast radius | 3. Implement elasticity – scale in/out automatically | 4. Think parallel – horizontal scaling over vertical scaling
What are the 3 ways to interact with AWS?
- AWS Management Console – web-based GUI, ideal for beginners | 2. AWS CLI – command-line tool, popular with engineers | 3. AWS SDKs – programmatic access (Python/boto3, Java, JavaScript, Ruby, Go, etc.)
When was AWS launched and with which service?
2006, with Amazon S3 (then SQS shortly after). Today AWS offers 300+ services.
What are the 6 AWS core service categories?
Compute, Storage, Networking & Content Delivery, Databases, Security/Identity/Compliance, Management & Governance.
