Chapter 02
Cloud concepts and billing
How a cloud is organised and paid for: service models, shared responsibility, regions, how accounts are structured, the free offers, pricing models and budgets. Includes a service name map across the three providers.
IaaS, PaaS and SaaS
Also called infrastructure as a service, platform as a service, software as a service, IaaS, PaaS, SaaS
- What
- IaaS rents you virtual machines, disks and networks to manage yourself. PaaS runs your code or database while the provider handles servers. SaaS is finished software you just use.
- Why
- The model decides how much you patch, scale and secure yourself, and so how much work and risk you take on.
- Example
- A VM running your own PostgreSQL is IaaS. A managed PostgreSQL service is PaaS. A hosted email product is SaaS.
Watch out
Running everything on VMs out of habit, then spending your weeks patching operating systems a managed service would handle.
Regions and availability zones
Also called region, availability zone, AZ, zone
- What
- A region is a geographic area with its own data centres. Inside it, zones are separate data centres with independent power and networking, close enough for fast links.
- Why
- Spreading an app across zones survives one data centre failing. The region you pick also sets latency to users, prices and which services exist.
Watch out
Building in the default region far from your users, or putting every instance in one zone and calling it highly available.
Projects, folders and the organisation
Also called project, folder, organization node, project ID
- What
- Every Google Cloud resource lives in a project, which has its own ID, enabled APIs, IAM and billing link. Projects can sit in folders under an organisation node.
- Why
- A project is the unit you secure, bill and delete. One project per app and environment keeps mistakes and costs contained.
gcloud projects create shop-dev-4821
gcloud config set project shop-dev-4821
gcloud services enable compute.googleapis.com
gcloud projects delete shop-dev-4821Watch out
Doing everything in the auto-created "My First Project" and never knowing which resources belong to what.
Google Cloud Free Trial and Free Tier
Also called free trial, welcome credit, always free, free tier
- What
- As of September 2026, new customers get 300 USD of welcome credit over 90 days. The Free Tier adds ongoing limits, such as one e2-micro VM a month in us-west1, us-central1 or us-east1 and 2 million Cloud Run requests a month.
- Why
- If you do not upgrade, the trial billing account closes and its resources stop, so the trial cannot bill you by surprise.
Watch out
Creating the free e2-micro in a region outside the three listed, where it is billed like any other VM.
On-demand, committed and spot pricing
Also called on-demand, reserved instances, savings plans, committed use discounts, spot
- What
- On-demand is pay per second or hour with no commitment. Committing to one or three years of usage buys a large discount. Spot capacity is spare capacity sold cheaply that can be taken back at short notice.
- Why
- The same workload can cost very different amounts depending on how you buy it, which is most of what cloud cost work is.
- Example
- AWS calls commitments Savings Plans and Reserved Instances, Azure calls them reservations and savings plans, Google Cloud calls them committed use discounts.
Watch out
Running a stateful database or a single important server on spot capacity and losing it mid-day.
Budgets and billing alerts
Also called budget, billing alarm, cost alert
- What
- A budget watches actual or forecast spend and emails you, or triggers an action, when it crosses thresholds you set, such as 50, 80 and 100 percent.
- Why
- It is the first thing to set up in any new account: most surprise bills are forgotten resources that a 10 USD alert would have caught in a day.
Watch out
Believing a budget is a hard cap. It alerts; it does not switch off your resources unless you wire up an action to do so.
Well-Architected frameworks
Also called Well-Architected Framework, pillars, architecture review
- What
- Each provider publishes a framework of design principles grouped in pillars such as security, reliability, performance, cost and operations, with review questions for a workload.
- Why
- It gives you a checklist for your own designs and the vocabulary that architecture reviews and associate-level exams use.
Watch out
Reading it cover to cover before building anything. Use it as a review checklist once you have something running.
Service map: compute and data
Also called AWS vs Azure vs GCP, service comparison, equivalent services
- What
- The same job has a different product name on each cloud. This table maps the compute, storage and database services you meet first.
- Why
- Knowing the equivalents lets you read tutorials, job posts and diagrams written for another provider and translate them to yours.
Job AWS Azure Google Cloud
VM EC2 Virtual Machines Compute Engine
Scale set Auto Scaling VM Scale Sets Managed inst. groups
Functions Lambda Functions Cloud Run functions
Containers ECS, Fargate Container Apps Cloud Run
Kubernetes EKS AKS GKE
Objects S3 Blob Storage Cloud Storage
Disks EBS Managed Disks Persistent Disk
Files EFS Azure Files Filestore
SQL RDS, Aurora Azure SQL Cloud SQL
NoSQL DynamoDB Cosmos DB Firestore, BigtableWatch out
Assuming equivalent means identical: limits, pricing units and defaults differ, so check the docs of your provider.
Service map: network, identity and operations
Also called AWS Azure GCP equivalents, service names
- What
- The networking, identity, monitoring and infrastructure as code services on each cloud, side by side.
- Why
- These are the services every project touches, whatever it runs on, and the ones exam questions compare most.
Job AWS Azure Google Cloud
Network VPC Virtual Network VPC
Firewall Security group NSG Firewall rules
L7 LB ALB App Gateway App Load Balancer
DNS Route 53 Azure DNS Cloud DNS
CDN CloudFront Front Door Cloud CDN
Identity IAM Entra ID, RBAC IAM
Secrets Secrets Manager Key Vault Secret Manager
Metrics CloudWatch Azure Monitor Cloud Monitoring
Audit log CloudTrail Activity log Cloud Audit Logs
IaC CloudFormation Bicep TerraformWatch out
Mapping VPC to VPC and stopping there: a Google Cloud VPC is global while AWS VPCs and Azure virtual networks are regional.
Go deeper
- AWS Cloud Practitioner EssentialsFree · coursesefism.com/resources/aws-cloud-practitioner-essentials
- Microsoft Learn: Azure Fundamentals (AZ-900) trainingFree · coursesefism.com/resources/microsoft-learn-azure-fundamentals
- Google Skills (formerly Google Cloud Skills Boost)Free · platformsefism.com/resources/google-cloud-skills-boost