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Meet virtual machines

Learn what a VM is and why teams run many machines on one host.

15 min 5-question quiz 1 code exercise

By the end of this lesson you can

Explain what virtual machines virtualize and what they isolate.

A virtual machine (VM) is software that behaves like a computer. A host machine runs a hypervisor, and the hypervisor runs guest operating systems as VMs. Each VM gets virtual CPU, memory, storage, and networking. This lets teams isolate workloads, improve hardware utilization, and run different operating systems on the same physical server.

vm_demo.py

1vms = [
2  {"name": "api-vm", "cpu": 2, "memory_gb": 4},
3  {"name": "db-vm", "cpu": 4, "memory_gb": 8}
4]
5print(len(vms))
6print(vms[0]["name"])

Output

2
api-vm

Think of a VM as a clean sandbox with its own kernel and userspace. Containers share a host kernel; VMs do not. That extra isolation costs more overhead, but it is useful for multi-tenant systems, OS testing, and security boundaries.

Key takeaways

Explain what virtual machines virtualize and what they isolate.
VMs are powerful when automation and guardrails stay strong.
Observe before scaling; recover before incidents become outages.

Lesson quiz

5 questions · pass with 4 correct · up to 50 XP

Passing this quiz completes the lesson and keeps your streak going. Questions you miss come back in review sessions later.

Practice: write Python

Write Python in the editor and run it against sample inputs. Python runs locally in your browser using a WebAssembly runtime.

Exercise 1

Count VM resources

+25 XP

Read two integers (vCPU count and memory in GB) for each of two VMs, then print the total as cpu=<sum> mem=<sum>.

Small host
Balanced VMs

main.py

Loading editor…

Python runs in a sandboxed browser worker with a 60 second time limit. Its runtime loads from the Pyodide CDN; your code stays in this browser.

Questions about this lesson

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