Cloud basics

A cloud database runs in and is managed through the cloud, often delivered "as a service" so the provider handles servers, patching, backups and scaling. What it is, and how it differs from self-managed.

A cloud server is a virtual server that runs in a cloud provider’s data centre and that you rent on demand, instead of buying and running your own hardware. How it works, and where it fits in cert study.

Docker is used to package applications and their dependencies into containers so they run consistently anywhere, which is why it underpins modern microservices, CI/CD and cloud-native development.

Google Cloud (GCP) is used for the full range of cloud computing — hosting, storage, databases, networking — and is especially known for data analytics, machine learning and Kubernetes.

You don’t need Linux to start learning cloud computing or pass foundational certifications, but for most hands-on cloud engineering roles it is genuinely important.

AWS is used for almost anything computing-related that used to require your own servers — hosting, storage, databases, analytics, machine learning and more, rented on demand.

The AWS Well-Architected Framework is AWS’s best-practice guidance for designing reliable, secure, efficient and cost-effective cloud workloads, organised into six pillars.

Microsoft Azure is used for the full range of cloud computing — hosting, storage, databases, analytics, AI and identity — and is especially popular with Microsoft-centric organisations.

Kubernetes is used to run, scale and manage containerised applications across many machines automatically — the standard way teams operate containers in production.

Docker builds and runs individual containers, while Kubernetes orchestrates many containers across a cluster of machines — they are used together, not against each other.

Terraform is a multi-cloud infrastructure-as-code tool, while AWS CloudFormation is AWS-native — the right choice depends on whether you work across clouds.

A bastion host is a hardened server that acts as a single, controlled entry point for administrators to access resources in a private network.

A container registry is a service that stores and distributes container images, so teams can push images they build and pull them to run anywhere.

A data pipeline is an automated series of steps that moves data from its sources to a destination, so raw data becomes usable for analytics, reporting or machine learning.

A hypervisor is the software layer that creates and runs virtual machines, allocating a physical machine’s CPU, memory and storage among them.

A NAT gateway lets resources in a private subnet reach the internet for outbound connections, while staying unreachable from the internet inbound.

A REST API is an API that follows the REST architectural style, using standard HTTP methods on resources identified by URLs. How REST works and why the cloud runs on it.

An SLA is a provider’s formal commitment to a level of service, usually availability, often backed by credits if it is not met — here is how to read one.

Blue-green deployment runs two identical environments and switches traffic to the new one once it is verified, for near-instant releases and instant rollback.

Canary deployment releases a new version to a small subset of users first, then gradually widens the rollout as it proves stable, limiting the impact of any problem.

Edge computing processes data close to where it is generated rather than sending everything to a central cloud data centre, cutting latency and bandwidth use.

GraphQL is a query language and runtime for APIs that lets a client ask for exactly the data it needs in one request. How it works and how it compares with REST.

Multi-tenancy is an architecture where one instance of a system serves multiple customers, with each tenant’s data and configuration kept logically isolated.

Virtualization abstracts physical computing hardware into virtual resources, so one physical machine can run many isolated virtual machines — it is the foundation of cloud computing.

Serverless lets a provider run your code on demand with no infrastructure to manage; containers package apps to run consistently anywhere but leave orchestration to you.

Terraform provisions and manages cloud infrastructure declaratively, while Ansible focuses on configuration management and app deployment — and many teams use both together.

A firewall is a security control that monitors and filters network traffic, allowing or blocking it based on rules — a barrier between trusted and untrusted networks.

A reverse proxy sits in front of backend servers and forwards client requests to them. How it differs from a forward proxy, what it is used for, and common examples.

A service mesh is an infrastructure layer that manages communication between microservices — traffic, security and observability. How it works, and when it is overkill.

A subnet is a logical subdivision of a larger network, splitting it into smaller segments so you can organise resources, control traffic and apply different rules to each.

A webhook is an automated message one application sends another when an event happens, delivered as an HTTP request to a URL you provide. How webhooks work and where they are used.

Big data refers to datasets so large, fast-moving or varied that traditional tools cannot practically store or process them — usually described by volume, velocity and variety.

Docker is a platform for building, packaging and running applications in lightweight, portable containers. Images, Dockerfiles, registries and how it relates to Kubernetes.

GitOps manages infrastructure and deployments by treating a Git repository as the single source of truth, with automated tooling reconciling the live system to match.

A message queue lets different parts of an application communicate asynchronously through a buffer — producers add messages, consumers process them later, decoupled and resilient.

A VPN creates a secure, encrypted connection over a public network, letting data travel privately as if two points were on the same private network — here is how it works.

Caching is storing copies of frequently used data in a fast, temporary location so it can be served quickly without repeating slower work each time. How it works, and its trade-offs.

DNS (the Domain Name System) translates domain names like example.com into the IP addresses computers use to find each other — here is how a lookup works and where it shows up in the cloud.

Observability is the ability to understand what is happening inside a system from the outside, by collecting and analysing its outputs — built on logs, metrics and traces.

Platform engineering builds internal developer platforms that give developers self-service, paved paths to build, deploy and run software, reducing cloud infrastructure complexity.

A data warehouse stores structured, processed data for fast analytics, while a data lake stores raw data of any type cheaply at scale — different needs, often used together.

Cloud native is an approach to building applications that fully exploits the cloud — containers, microservices and automation — not just running old software on cloud servers.

ETL is the process of pulling data from source systems, transforming it into a clean format, and loading it into a destination for analysis; ELT loads first and transforms after.

Google Cloud Platform (GCP) is Google’s cloud computing platform — on-demand computing, storage, analytics and AI services, and the third of the big three clouds alongside AWS and Azure.

Terraform is HashiCorp’s open-source infrastructure-as-code tool: define cloud infrastructure in declarative files and provision it across AWS, Azure, GCP and more.

High availability minimises downtime by recovering quickly from failures; fault tolerance keeps running with no interruption at all. The distinction, the cost trade-off, and why exams test it.

A monolith builds an application as one unified unit; microservices split it into small independent services that communicate over the network. The real trade-offs, honestly compared.

Block storage splits data into fixed blocks for one machine, file storage organises it into shared folders, and object storage keeps self-contained objects at huge scale. When to use each.

Relational databases store data in structured tables with schemas and relationships; NoSQL trades that structure for flexibility and scale. How each works and how to choose per workload.

A content delivery network (CDN) is a globally distributed set of servers that cache your content close to users, so pages load faster and origin servers carry less load.

A load balancer distributes incoming traffic across multiple servers so no single server is overwhelmed, keeping applications available, responsive and scalable.

A virtual private cloud (VPC) is your own logically isolated network inside a public cloud, where you control IP ranges, subnets, routing and security boundaries.

An API is a defined set of rules that lets one piece of software request services or data from another without knowing its internals. How APIs work and why the cloud runs on them.

Auto-scaling automatically adjusts computing resources up or down with demand, so you have capacity when traffic is high and stop paying for idle servers when it is low.

A CI/CD pipeline is an automated workflow taking code from commit through building, testing and deployment, so releases are frequent and reliable. The stages, the tools and why it works.

Disaster recovery is your plan for restoring systems after a major disruption. RTO is how quickly you must be back up; RPO is how much data you can afford to lose. Both explained simply.

Encryption scrambles data into unreadable ciphertext only a key can reverse. In the cloud it protects data at rest (stored) and in transit (moving) — both explained for beginners.

Identity and access management (IAM) is the framework controlling who can access which resources and what they may do — the foundation of cloud security, explained for beginners.

Kubernetes is an open-source system for automating the deployment, scaling and management of containerised applications across a cluster of machines.

Microsoft Azure is Microsoft’s cloud computing platform — on-demand computing, storage, networking, databases and AI services, billed by usage, and one of the two largest clouds alongside AWS.

Zero trust is a security model where no user, device or request is trusted by default — every access is authenticated, authorised and continuously validated. The model, explained simply.

An AWS Region is a separate geographic area containing multiple isolated Availability Zones — discrete data centres with independent power and networking. How the hierarchy works.

A virtual machine virtualises an entire computer including its own OS; a container packages just an application and its dependencies and shares the host’s kernel — lighter and faster to start.

AWS pricing is consumption-based — you pay for what you use, per service, with no upfront commitment required. The purchasing models, hidden cost dimensions and tools, explained.

IaaS, PaaS and SaaS differ in how much of the technology stack the provider manages versus you — from raw infrastructure to finished applications. A plain-English guide with examples.

Public, private and hybrid cloud describe where infrastructure lives and who shares it — provider-owned and multi-tenant, dedicated to one organisation, or a deliberate mix of both.

The shared responsibility model divides security duties: AWS secures the cloud itself — hardware, software, facilities — while you secure what you put in it. The split, explained clearly.

Cloud computing is the on-demand delivery of computing resources — servers, storage, databases, networking — over the internet, paid for as you use them. Here is how it works and why it matters.

DevOps is a set of practices and a culture that shortens the path from writing code to running it reliably in production — not a job title or a tool. What it really means, explained plainly.

Infrastructure as code (IaC) means defining servers, networks and other infrastructure in version-controlled files applied repeatably — not console clicks. How it works and why it matters.

Serverless computing means running code or using services without provisioning or managing servers — the provider handles capacity, scaling and patching, and you pay only for what you consume.