IT Support, Networking and Infrastructure
Virtualisation and server infrastructure
Between the desktop and the cloud sits a layer many organisations still run themselves: physical servers in a rack, a hypervisor on top and dozens of virtual machines sharing the hardware. Looking after it means thinking about capacity, storage and failure in ways desktop work never asks for. This page covers that layer and marks the point where it hands over to the cloud field.
Why this topic exists: Hypervisors, virtual machines and server hardware sit between the desktop and the cloud (A+ Core 1 Virtualization and Cloud Computing 11 %; SFIA Infrastructure operations; VMware and Server+).
A server room today often runs many more systems than it holds physical machines. The reason is the hypervisor, a thin layer of software that divides one physical host into many virtual machines, each believing it has its own processor, memory, disks and network card. Type 1 hypervisors such as VMware vSphere, Hyper-V and Proxmox run directly on the hardware and carry production workloads; type 2 hypervisors run as an application on a desktop and are what most people learn on.
A+ Core 1 introduces the subject in its Virtualization and Cloud Computing domain, worth 11 %, covering virtual machines, hypervisors and the cloud service models. SFIA's infrastructure operations skill frames the professional work as provisioning, running and tuning infrastructure whether it is physical, virtual or cloud-based, and that breadth reflects the reality of most estates: a mixture of all three.
What a virtual estate asks of you
- Capacity. Hypervisors let you promise virtual machines more processor and memory than the host physically has. That works until several of them get busy at once.
- Shared storage and networking. Moving a running machine between hosts, or restarting it elsewhere after a failure, depends on storage and networks that every host can reach.
- Patching the layer underneath. A hypervisor vulnerability exposes every guest on the host, so the host needs its own maintenance windows.
- Sprawl. Creating a virtual machine takes minutes, and forgotten ones keep consuming resources and missing updates for years.
- Licensing. Hypervisor and guest operating-system licences follow their own rules, and vendors change them.
Virtual machine, container, rented server
The same idea appears under several names. A VPS is a virtual machine a hosting company rents out by the month, and a dedicated server is the whole physical box. IaaS turns virtual machines into something you create through an API and pay for by use. Containers go lighter still, sharing the host's kernel instead of emulating hardware, which makes them start in seconds but isolates them less strongly. Who patches and watches the machine is a separate question from where it runs, and the managed versus unmanaged guide walks through it.
A snapshot is a bookmark
Take a snapshot before an upgrade and remove it afterwards. Snapshots live on the same storage as the machine, grow with every change and slow it down over time; they are a rollback point, not a place to keep history.
Newcomers tend to build a single impressive host and forget what happens when it fails. Plan for the host going down from day one. A+ supplies the vocabulary, Cloud+ extends it into cloud operations and RHCSA proves the Linux administration running inside the guests. Continue with backup, storage and disaster recovery, the server operating systems, with Linux administration on one side and Windows Server and Active Directory on the other, and the rented version of all this in cloud fundamentals and containers and Kubernetes.
Within this topic
- Backup, storage and disaster recoveryStorage tiers, backup schedules, restore tests and continuity plans are the part of infrastructure nobody funds until the day it is needed (SFIA Storage management and Continuity management; Network+ disaster recovery under Network operations; A+ Core 2 operational procedures).
- IT fundamentalsWhat computers, networks, operating systems and data are for, before fixing any of them: the scope of Tech+ and of the first weeks of every support course (SFIA Delivery and operation; A+ Core 1).
- Hardware, mobile devices and troubleshootingComponents, peripherals, mobile devices and the troubleshooting method are the largest part of A+ Core 1 (Hardware 25 %, Hardware and Network Troubleshooting 28 %, Mobile Devices 13 %, read 2026-09-26).
- Operating systems: Windows, macOS, LinuxInstalling, configuring and securing desktop operating systems is A+ Core 2's largest domain (Operating Systems 28 %) and the daily ground of support work.
- Linux administrationThe command line, package management, filesystems, users, services, scripting and networking as LPIC-1 objectives v5.0 lay them out (topics 101–110); Linux+ and RHCSA test the same ground.
- Windows Server and Active DirectoryDomains, group policy, file and print, identity for the desktop estate: the server side of most business IT (SFIA System software administration; Microsoft's Windows Server hybrid administrator track).
- Networking fundamentalsThe OSI and TCP/IP models, addressing, subnetting, DHCP and DNS are the first domains of Network+ (Networking concepts 23 %) and CCNA (Network Fundamentals 20 %).
- IT support and the service deskTickets, incidents, requests, remote support and the operational procedures of A+ Core 2 (21 %): the job most people enter IT through (Google IT Support; ITIL's service desk and incident practices).
- IT service management (ITIL)The practices that run IT as a service: incident, problem, change enablement, service level, continual improvement (ITIL's practice model, Version 5 since February 2026 with ITIL 4 in parallel; ITIL Foundation; ServiceNow CSA).
- Scripting and automation for administratorsPowerShell, Bash and Python are how administrators stop doing the same thing twice (LPIC-1 topic 105; CCNA Automation and Programmability 10 %; SFIA System software administration).
Concepts to know
Glossary entries with the reason each one matters here.
- VPS
A VPS is a virtual machine sold by the month.
- Dedicated Server
The physical machine the hypervisor runs on.
- IaaS
Where virtualisation becomes cloud.
- Containers
The lighter alternative to a virtual machine.
Certifications that test it
Vendor exams and free certificates; facts, cost and the preparation path are on each page, and the certifications hub has them all.
- CompTIA · 220-1201 + 220-1202CompTIA A+Virtualisation and cloud is a Core 1 domain.
- CompTIA · CV0-004CompTIA Cloud+Where virtualisation becomes cloud operations.
- Red Hat · EX200Red Hat Certified System Administrator (RHCSA)The Linux administration inside the guests; the performance-based exam runs on a live RHEL system.
Guides that apply
- Managed vs unmanaged hosting
Who runs the server is the same question in a rack and on a hosting plan.
Tools of the trade
- VMware vSphere
The data-centre hypervisor.
Frequently asked
- What is the difference between type 1 and type 2 hypervisors?
- A type 1 hypervisor runs directly on the server's hardware and is built for production. A type 2 hypervisor is an application on an ordinary operating system, convenient for labs and testing but slower and less robust.
- Which hypervisor should I learn?
- Whatever runs where you work or hope to work. The concepts of virtual switches, shared storage, snapshots and migration carry across products, so a home lab on a free hypervisor is useful preparation for any of them.
- Is on-premises virtualisation giving way to the cloud entirely?
- Not entirely. Many organisations keep workloads in-house for cost, latency, data-location or regulatory reasons and run a hybrid of both. Understanding virtualisation also makes the cloud easier to grasp, because much of it is virtualisation sold as a service.
Courses in the directory
85 courses are filed here; the top 6 by our ranking, details and the provider link on each course page.
Last reviewed 26 September 2026 · Getting Digital