Stop 18 · Cloud & HostingTopics · 1/11

Cloud Computing Basics

In short

Buying servers means paying a big amount upfront and guessing your traffic for years. The cloud lets you rent exactly what you need by the hour, and give it back when you're done.

Renting computing resources (servers, storage, databases) from a provider instead of owning physical hardware — the default way backend systems are hosted today.

The purple blob receives a key in front of a decorated rented banquet hall, with unused bricks nearby.

Think of it like this

Renting the wedding hall

Nobody builds a banquet hall for one wedding. You rent one for the day, with chairs, lights and a generator included, and return the keys after. The cloud is that hall for computers: someone else owns the building, you pay for the hours you use.

Watch it happen

The layers of cloud services

Cloud services

IaaS

PaaS

SaaS

EC2, VMs

Render, Railway

Gmail, Slack

1/4Cloud services come in layers. The higher you go, the less you manage yourself.

The big ideas

What you need to know

Pay as you go

You're billed per second, hour or request. Great for spiky traffic, painful if you forget a big server running.

Scale in minutes

Need ten more servers for a sale? Ask for them by API, use them, then delete them.

Regions and zones

Providers run data centres in many regions, each split into availability zones. Spread across zones so one outage doesn't sink you.

Shared responsibility

The provider secures the hardware and buildings. You secure your code, passwords, open ports and data.

See it in code

Walk through the code

bash

1# Who am I, and which region am I using?2aws sts get-caller-identity3aws configure get region4 5# List running virtual machines in that region6aws ec2 describe-instances \7  --filters Name=instance-state-name,Values=running \8  --query "Reservations[].Instances[].[InstanceId,InstanceType]" \9  --output table10 11# See this month's cost so far (Cost Explorer must be enabled)12aws ce get-cost-and-usage --time-period Start=2026-10-01,End=2026-10-27 --granularity MONTHLY --metrics UnblendedCost

1/3Check which account and region your commands will hit before creating anything.

Every click in the cloud console is an API call underneath. Learning the CLI makes those calls repeatable and scriptable.

Save yourself the pain

Common mistakes

Oops

Creating resources for a tutorial and forgetting them afterwards.

Do this instead

Set a budget alert on day one and delete what you don't use. Idle servers still bill by the hour.

Oops

Assuming the cloud provider secures your app for you.

Do this instead

They secure the data centre. An open database port or a leaked key is still entirely your problem.

Your mission

Set up a safe cloud account

~25 min

Quick check

You deploy a Docker image and the platform handles the servers, scaling and OS patches. Which model is that?

Go deeper

1Compare IaaS, PaaS and serverless as different levels of cloud abstraction.
2Identify which category (IaaS/PaaS/serverless) a few services you know fall into.
3Learn why 'the cloud' is really just someone else's data center, with a lot of automation on top.