Cloud services and virtualization

Virtualization enables multiple machines or isolated environments to share physical hardware. Cloud services provide resources as services over a network, typically with self-service capabilities and the ability to scale. You can virtualize hardware you own yourself, and a virtualized environment is not automatically a cloud.

Here, you will explain what a VM and a container share with the host, and distinguish between IaaS, PaaS, and SaaS using your own examples. You do not need to purchase a cloud service. Use a VM that already has access, or use the provided examples in the text.

Place in subject matter: This level explains virtualization within an operations architecture. [[Operating System Level 3 - The Operating System Kernel|The Operating System Kernel]] explains what a guest operating system has its own version of. [[Operations Architecture Level 0 - Operating Systems, VMs, and Containers|Overview Map]] shows part-whole relationships, technical relations, and paths to practical tasks.

What is virtualization?

Virtualization means running multiple “virtual” machines on the same physical machine. Instead of having a separate physical server for the web server, one for the database, and one for the file server, you can run all three as virtual machines on a single machine.

The software that makes this possible is called a hypervisor:

What is a virtual machine (VM)?

A VM is a virtual machine with virtual CPU, memory, and disk. It runs a guest operating system with its own kernel, while the hypervisor provides access to the physical hardware. Proxmox VE uses Linux and KVM to run VMs; “directly on the server” does not mean that the platform lacks an operating system kernel.

Benefits of VMs:

• Isolation - A fault in one guest operating system usually does not need to stop the other VMs. However, they still share host, storage, and other resources and can be affected by common failures or resource shortages.
• Flexibility - You can run different operating systems on the same machine (e.g., Ubuntu and Windows Server).
• Snapshot/backup - You can take a snapshot of a VM and roll back if something goes wrong.
• Resource utilization - A physical machine with plenty of RAM and CPU can run many VMs.

What are containers?

A Linux container runs the application in an isolated environment and shares the kernel of the Linux system it is running on. A virtual machine has its own guest operating system with a separate kernel.

[[Containerization Level 1 - Containers and Virtual Machines|Containers and Virtual Machines]] owns the illustrated comparison and also shows how multiple containers can run inside one virtual machine. Use this to explain what shares the kernel and what happens if the virtual machine is shut down. [[Docker Level 0 - What Is Docker|Docker Level 0]] then introduces a specific tool for application containers.

In practice, we often use both: VMs hosting Docker containers.

Cloud Services

In a public cloud, a provider owns and operates the infrastructure, and you order resources over the network. A private cloud is dedicated to one organization and can be operated by the organization itself or by a provider. Self-service, shared resource pools, scalability, and usage metering are key characteristics of the cloud.

Service Models

There are three main models for cloud services:

Delivery models

Cloud services can be delivered in various ways:

VPS: A common cloud solution

A VPS (Virtual Private Server) is one of the most common IaaS solutions. You rent a virtual machine from a cloud provider and have full control over it, just as if you had your own dedicated server.

Typical use cases:

• Running a web server
• Setting up a VPN service
• Hosting an application (e.g., Flask + database)
• Testing things without risking your own hardware

Examples of providers that offer virtual servers:

• Akamai (Linode)
• DigitalOcean
• Hetzner
• Microsoft Azure

Local vs. Cloud

Many companies use a combination of local servers and cloud services. Here are some factors to consider:

Task 1 - Investigate a Virtual Machine

Use a virtual machine (VM) you already have access to. If you are using Proxmox, refer to [[Serverinstallation Level 3 - Navigate in Proxmox VE|Navigate in Proxmox VE]] where you read the CPU, RAM, and disk details. To create a new VM, follow the instructions in [[Serverinstallation Level 2 - VM in Proxmox|the installation guide]]. You do not need to install an additional hypervisor on your own computer for this task.

• How much CPU, RAM, and storage is allocated to the VM?
• What resources are shared with other VMs on the physical host?
• What can happen if multiple VMs collectively require more memory than the host has available? Explain without changing any resource allocations.

If you do not have a VM available, use the suggested configurations from the installation guide as a hypothetical example. Clearly state that your answer describes such an example rather than documenting a completed setup.

Exercise 2 - Start a container with Docker

Use the Nginx container from [[Containerbruk Level 1 - Kjor og undersog en container|Run and inspect a container]] if you have already completed the exercise. If you removed it, recreate it as shown in the container exercise. If Docker is missing, start by following the installation. Explain which kernel the container uses, and compare its startup process to that of a virtual machine. If Docker is not available, use the containerization figures to explain the difference without pretending you performed a practical test.

Task 3 - Which cloud services are you already using?

Think about which services you use on a daily basis:

• Microsoft 365 (Word, Teams, OneDrive) is SaaS
• GitHub Pages for hosting a website is PaaS
• A VM in Proxmox demonstrates virtualization. It is not automatically IaaS; it depends on how the resources are provided and managed as a service.

Can you categorize other services that you use?

Task 4 - Where is your data located?

Go to Microsoft Privacy Dashboard and see what Microsoft stores about you. Also, check the terms of a cloud service you use:

• Where in the world is the data stored?
• What happens to the data if you delete your account?
• Do you own your data, or does the provider?

These questions are especially important in light of GDPR and privacy.

Check the explanation

Orally or in writing, explain why a virtual machine (VM) in Proxmex is not automatically a cloud service. Then choose one example of each of IaaS, PaaS, and SaaS, and describe what the customer and the provider manage in each case. If you merely list names, use the service model table to explain the division of responsibilities.

Summary

• Virtualization allows you to run multiple services on the same hardware, either as VMs or containers
• Cloud services provide resources over the network with features such as self-service and scaling
• IaaS, PaaS, and SaaS describe how much responsibility you have yourself
• In practice, many use a hybrid solution combining both local and cloud-based services
• The choice between local and cloud depends on control, cost, scalability, and privacy

Sources: NIST: definition of cloud computing and Proxmox VE: KVM and virtual machines.