LPIC-3 305-300: what the virtualisation exam expects

LPIC-3 305-300 is a short exam that punishes shallow preparation. Ninety minutes, sixty questions, and a meaningful proportion of them expecting you to type a command or option exactly rather than pick it from four choices.

How is the exam structured?

Property	Value
Questions	60
Time	90 minutes
Scoring	Scaled 200-800
Pass mark	500
Format	Multiple choice and fill-in-the-blank
Validity	5 years

Ninety seconds per question is the headline number, but it is misleading as an average. Multiple-choice items on concepts go quickly. Fill-in-the-blank items asking for a specific virsh subcommand or a libvirt XML element do not.

Budget your time on the assumption that a third of the paper will take twice as long as the average.

The fill-in-the-blank problem

This is the single biggest difference between LPIC exams and most vendor certifications, and it changes how you must study.

Recognition is not enough. If you have only ever read about virsh you will recognise virsh list --all when you see it. Under exam conditions, asked to type the command that lists all domains including inactive ones, recognition does nothing for you.

The countermeasure is simple and unpopular: use the tools. Build a small lab — a spare machine, a nested virtualisation setup, or even a modest cloud instance — and actually run the commands. Muscle memory formed by typing a command twenty times is what fill-in-the-blank items are testing.

Reading a book about virtualisation will not pass this exam.

What is in scope?

Three topic areas:

Full Virtualization

The largest area. Xen and KVM as hypervisors, QEMU, and libvirt as the management layer above them. Expect questions on:

• Hypervisor architecture and the difference between type 1 and type 2
• KVM setup and the role of QEMU
• virsh operation: domains, networks, storage pools
• libvirt XML domain definitions and what the elements mean
• Virtual networking modes: bridged, NAT, isolated
• Storage backends and disk image formats

Container Virtualization

Concepts first, then implementations. The underlying kernel mechanisms — namespaces and cgroups — are examinable in their own right, not merely as background.

• Namespaces, cgroups and what each one isolates
• LXC and LXD operation
• Docker: images, containers, volumes, networks, registries
• Container security boundaries and their limits

A common failure is arriving with practical Docker experience but no grounding in the kernel primitives beneath it. The exam asks about both.

VM Deployment and Provisioning

The smallest area, and the one candidates most often under-prepare.

• cloud-init and its configuration
• Vagrant workflow and Vagrantfiles
• Packer for image building
• General provisioning patterns

If you have never used cloud-init directly, spend a weekend on it. It appears more often than its share of the objectives suggests.

The LPIC-2 prerequisite

This catches people out, so it is worth stating plainly.

You may sit 305-300 whenever you like. LPIC-3 is only awarded while you hold an active LPIC-2. If your LPIC-2 lapsed three years ago, passing 305-300 will not produce a certification until you renew it.

Check the status of your LPIC-2 before booking, not after passing.

A four-week plan for an experienced Linux admin

Assuming you already administer Linux systems day to day:

Week 1 — Full virtualisation. Build a KVM host. Create three VMs by hand with virsh, not a GUI. Read the generated XML and change things in it deliberately.

Week 2 — Networking and storage. Configure bridged, NAT and isolated networks. Create storage pools of each type. Break them and fix them.

Week 3 — Containers. Start with namespaces and cgroups directly — unshare, nsenter, the cgroup filesystem — before touching Docker. Then LXC, then Docker. The order matters; it makes Docker’s behaviour obvious rather than magical.

Week 4 — Provisioning and rehearsal. cloud-init, Vagrant, Packer. Then two full timed practice sets, with a hard 90-minute limit and no lookups.

Sitting the paper

Three tactics that consistently help:

1. Answer the multiple-choice items first. They are faster, and banking them protects against running out of time on syntax questions.
2. Type exactly what is asked. If the question says “the command including options”, a bare command name may be marked wrong. Read the instruction, not just the question.
3. Leave nothing blank. There is no negative marking, so an educated guess strictly dominates an empty field.

The exam is fair and well constructed. It simply expects you to have used the technology rather than read about it, and it has an unusually direct way of finding out which one you did.