Cloud Services and Virtualisation

Virtualisation doth permit manifold machines or bounded realms to share physical hardware. Cloud services offer resources as a service o’er the network, commonly with self-service and the capacity for scaling. Thou mayst virtualise hardware that thou dost own thyself, yet an environment of virtualisation is not in itself a cloud.

Herein shalt thou expound what a VM and a container partake with their host, and distinguish IaaS, PaaS, and SaaS by thine own examples. ‘Tis no need to purchase a cloud service. Employ a VM unto which thou hast access already, or use those given examples within the text.

Place in Curriculum: This level doth explain virtualisation within an operational architecture. [[Operating System Level 3 - The Operating System Kernel|The Operating System Kernel]] expounds upon what a guest operating system hath its very own version of. [[Operations Architecture Level 0 - OS, VM and Containers|The Overview Map]] sheweth part-whole relations, technical bonds, and paths towards practical tasks.

What is Virtualization?

To virtualize signifyth to runne divers ‘virtual’ machines upon one singular physical machine. In lieu of possessing a distinct physical server for the webe-server, another for the database, and yet another for the file-server, thou mayst operate all three as virtual machines upon one and same device.

The software that rendereth this feasible is named an hypervisor:

What is a Virtual Machine (VM)?

A VM is a virtual machine with vCPU, memory and disk. It runneth a guest operating system with its own kernel, whilst the hypervisor granteth access unto the physical hardware. Proxmox VE employeth Linux and KVM to execute VMs; “directly upon the server” signifieth not that the platform lacketh an operating system core.

Advantages of VMs:

• Isolation - A fault in one guest operating system need not halt the other VMs. Yet they do share host, storage and sundry resources, and may be affected by common faults or want of resource.
• Flexibility - Thou mayst operate diverse operating systems upon the same machine (e.g., Ubuntu and Windows Server).
• Snapshot/backup - Thou mayst take a snapshot of a VM and revert thereto if naught go well.
• Resource utilization - A physical machine bountiful in RAM and CPU may sustain many VMs.

What are containers?

A Linux container runneth the application within an isolated realm yet shareth the core of that Linux system upon which it dwelleth. A virtual machine possesseth its own guest operating system with a distinct kernel thereof.

Containers and Virtual Machines doth hold the illustrated comparison and sheweth also how manifold containers may be wrought within one single virtual machine. Employ thou this to declare what divideth the kernel, and what cometh to pass if the virtual machine is brought low. Thenforth Docker Level 0 presenteth a specific instrument for application containers.

In deed, we oft employ both parts: virtual machines that serve as hosts unto Docker containers.

Cloud Services

In a public cloud, a provider owneth and maintaineth the infrastructure, whilst thou dost order resources through the network. A private cloud is for one sole enterprise, which may be maintained by that very enterprise itself, or by a provider. Self-service, shared pools of resource, scaling, and the measuring of usage are central traits unto the cloud.

Models of Service

There exist three principal models for cloud services:

Modes of Delivery

Cloud services may be rendered in sundry fashions:

A VPS: An Ordinary Cloud Solution

A Virtual Private Server is amongst the most common of IaaS wares. Thou rentest a virtual machine from a cloud provider and hast full dominion o’er it, as though thou didst possess thine own server.

Common uses thereof:

• To runne a web-server
• To set up a VPN service
• To host an application (e.g., Flask + database)
• To test matters without risking one’s own hardware

Examples of providers who offer such virtual servers:

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

Local vs. the Heavens

Many a company doth employ a mingling of local servers and cloud services. Here are some matters to ponder:

Task the First — To Examine a Virtual Machine

Employ thou a virtual machine unto which access is already granted. If Proxmox be thine instrument, then peruse Naviger i Proxmox VE wherein the count of CPUs, RAM, and disk mayst read. Should’st thou desire to create a new one, do follow the guide. It need not be that an extra hypervisor be installed upon thy own device for this task.

• What measure of CPU, RAM, and storage hath been allotted unto the virtual machine?
• What resources are shared with other machines upon the physical host?
• What mischief might arise if several such machines, in sum, require more memory than the host possesseth? Explain without altering the resources themselves.

If no virtual machine be at hand, employ the resource proposals within the installation guide as a hypothetical example. Mark thou the answer thus: ‘tis but an explication of the instance, not a completed act of installation.

Task Two - Commence a Container via Docker

Employ the Nginx vessel hailing from [[Containerbruk Level 1 - Kjor og undersog en container|To Run and Examine a Vessel]], shouldst thou have already completed said exercise. Hast thou removed it? Then create anew as the vessel’s trial doth show. Lacking Docker, begin with the installation. Declare which kernel the vessel employeth, and compare its awakening unto that of a Virtual Machine. Shouldst thou lack access to Docker, use the figures of containment to expound upon the distinction without feigning hath performed a practical assay.

Task the Third - What Cloud Services dost thou already employ?

Ponder upon those services which serve thee in thy daily life:

• Microsoft 365 (Word, Teams, OneDrive) is a Software as a Service
• GitHub Pages, to lodge a website, is a Platform as a Service
• A Virtual Machine within Proxmox doth display virtualization. It is not of itself an Infrastructure as a Service; it dependeth on how resources are granted and kept as a service.

Canst thou categorize other services that thou makest use of?

Task the Fourth - Where Doth Thy Data Reside?

Go unto the Microsoft Privacy Dashboard and behold what Microsoft doth store concerning thee. Examine also the terms of a cloud service which thou dost employ:

• Where in the world are the data stored?
• What shall befall the data shouldst thou delete thine account?
• Dost thou own thy data, or doth the provider so claim?

These questions are most especially vital with regard to GDPR and privacy.

Verifie thy explication

Declare forthwith by word of mouth or pen why a virtual machine within Proxmox is not of itself a cloud service. Thereafter select one exemplar each of IaaS, PaaS, and SaaS, and set down what both customer and provider doth manage in every instance. Shouldst thou but recite names alone, employ the table of service models to elucidate the division of duties.

A Summing Up

• Virtualisation granteth thee power to runne divers services upon one hardware, whether as virtual machines or containers
• Cloud Services doth offer resources o’er the network with self-service and scaling amongst other things
• IaaS, PaaS, and SaaS bespeak how much burden thou dostst bear thyself
• In practice, many use a hybrid solution with both local and cloud-based services
• The choice ‘twixt local and cloud is of control, cost, scalability, and privacy

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