More clarity on difference between VM and VM instances and Availability Sets (AS)

Marouf Ali 270

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Hello everyone,

On the internet, I saw the difference in the image above- between a VM and a VM instance.

So, I infer from this that VMs have different OS systems and all of them operate independently.

But VM instances are templates or blueprints of a VM, that can be spun or downsized as needed. They also run independently but based on the same initial config that they got from the template.

==> Obviously VM instances are much faster than VMs because they are based on configs and don't need an OS or CPU and other resources unlike VMs. Please correct the above. Am I right?

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Also, are Availability Sets are specifically designed to handle VM instances?

So, when you deploy VMs into an availability set, Azure distributes the VMs across multiple physical servers, network switches, and power sources within a data center:

Does it mean deployment of VM instances across multiple physical servers....because based on the difference above, it would be time consuming for VMs to be deployed quickly across multiple servers? And as mentioned in the module, we are paying for VM instances that we create (obviously, using Azure portal or CLI etc.)

Kindly, please clarify,

Thank you

Marouf

Marouf Ali 270 Reputation points

2024-11-05T17:24:18.21+00:00

Hello,

Based on the response below:

1)Can we say that VM and VM instances are the same thing, except that they differ in their deployments?

2)So, can we say that VM instances along with their OS, CPU, memory and other resources -can be spun fast compared to a VM?

3)Can I say that deployment of a VM or a VM instances depends on the situation. So, if a company wants to test something quickly on the go, it can use a VM instance and likewise if an organization wants to develop and test or troubleshoot its applications, it would be better to deploy a VM. Am I right?

4)Are there situations where VM and VM instances might be deployed together?

5)In an on-premises datacenter, if a VM is created by the hypervisor on the local physical server, is it possible for a VM instance to be instantiated on the same physical server?

6)If answer to question 5 is yes, then who creates the VM instance in the datacenter - hypervisor or some other virtualization software?

7)In Azure, VM instances are created by Azure portal, CLI, Powershell, IaC and ARM templates - is that right?

Kindly, please clarify.
anashetty 740 Reputation points Microsoft Vendor

2024-11-06T11:11:10.26+00:00

Hi Marouf Ali,

Here are the solutions for the queries you have:

1)Can we say that VM and VM instances are the same thing, except that they differ in their deployments?

A VM refers to a single virtual machine you create and configure with specific settings. VM instances are generally created from predefined images or snapshots and deployed in a standardized manner. This setup allows for faster and more scalable deployment, such as in Azure’s Virtual Machine Scale Sets (VMSS). The VM and VM instance are fundamentally the same in resources (OS, CPU, memory) but differ in deployment and scalability.

2)So, can we say that VM instances along with their OS, CPU, memory and other resources -can be spun fast compared to a VM?

Yes, VM instances within a Scale Set can be provisioned more quickly because they are based on a pre-configured template and can automatically scale out based on demand.

3)Can I say that deployment of a VM or a VM instances depends on the situation. So, if a company wants to test something quickly on the go, it can use a VM instance and likewise if an organization wants to develop and test or troubleshoot its applications, it would be better to deploy a VM. Am I right?

Yes, it’s correct. For tasks that require rapid provisioning or scaling, such as testing something quickly, using a VM instance within a Virtual Machine Scale Set is ideal and for application development, testing, or troubleshooting, deploying a standalone VM can provide greater flexibility and customization.

4)Are there situations where VM and VM instances might be deployed together?

Yes, there are scenarios where both custom virtual machines (VMs) and VM instances might be deployed together to balance flexibility and scalability.

5)In an on-premises datacenter, if a VM is created by the hypervisor on the local physical server, is it possible for a VM instance to be instantiated on the same physical server?

Yes, on-premises hypervisors can run multiple VMs or VM instances on the same physical server, depending on hardware capacity.

6)If answer to question 5 is yes, then who creates the VM instance in the datacenter - hypervisor or some other virtualization software?

In an on-premises setup, the hypervisor is responsible for creating and managing both VMs and VM instances. The hypervisor manages resource allocation, isolation, and performance across all VMs on the physical server.

7)In Azure, VM instances are created by Azure portal, CLI, PowerShell, IaC and ARM templates - is that right?

Yes, in Azure, you can create VM instances using a variety of methods, including the Azure Portal, CLI, PowerShell, Infrastructure as Code (IaC) tools, and Azure Resource Manager (ARM) templates.

Please let us know if you have any further queries. I’m happy to assist you further.

Thankyou.
anashetty 740 Reputation points Microsoft Vendor

2024-11-07T09:51:21.18+00:00

Hi Marouf Ali,

I hope you're doing well. Just checking in to see if you had a chance to see my response to your question. If you have any further queries, please do let us know.

Thank you.
Marouf 0 Reputation points

2024-11-07T18:37:00.1033333+00:00

Hello, Thanks very much for your response. I understood everything. Basically, a VM instance is a copy of the VMs OS, resources, CPU etc. And that can be scaled up and down instantly as per demands of te project. However all VM instances have the same OS and CPU like the original template. But a VM is unique and has the OS and resources of the server. So, wouldn't multiple VMs means the same as VM instances? Or are VMs different in this aspect? Thank you
anashetty 740 Reputation points Microsoft Vendor

2024-11-08T11:34:11.4166667+00:00

Hi Marouf,

Thank you for coming back, I'm glad to hear that my response helped you.
As per your question Multiple VMs offer flexibility and customization for specialized tasks, whereas VM instances emphasize uniformity and scalability, making them suitable for large-scale deployments.
Marouf 0 Reputation points

2024-11-08T11:54:53.13+00:00

Ah, I see now. So multiple VMs usually are deployed for different tasks whereas VM instances are scalable and generally large scale deployments of the same tasks. Right?
anashetty 740 Reputation points Microsoft Vendor

2024-11-08T14:19:41.4433333+00:00

Hi Marouf,

Multiple VMs are useful when applications need isolated or unique environments, such as for development and testing where each VM might require a different setup. VM instances are intended for scalable, large-scale deployments of identical tasks, allowing you to quickly add or remove instances to handle varying demand.

Please let us know if you have any further queries. I’m happy to assist you further.

Thank you.
anashetty 740 Reputation points Microsoft Vendor

2024-11-11T10:27:55.8266667+00:00

Hi Marouf,

I hope you're doing well. Just checking in to see if you had a chance to see my response to your question. If you have any further queries, please do let us know.

Thank you.

Accepted answer

anashetty 740 Reputation points Microsoft Vendor

2024-11-05T14:04:05.3466667+00:00

Hi Marouf Ali,

Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.

Here is the detailed information about your query.

You are partially correct regarding VM and VM Instance. VM instances are templates or blueprints of a VM, that can be spun or downsized as needed but VM instances still require an operating system (OS), CPU, memory, storage, and other resources just like traditional virtual machines (VMs). The main distinction isn’t that they lack these resources but rather how they’re created and deployed.

Please refer to below document for more information https://learn.microsoft.com/en-us/azure/virtual-machines/overview

Yes, Availability Sets in Azure are specifically designed to enhance the availability and reliability of virtual machines (VMs), including VM instances. When you deploy virtual machines (VMs) within an Availability Set in Azure, the platform distributes them across various physical servers, network switches, and power supplies within a data center. This setup ensures that a failure in one physical component, such as a server or power source, will not impact all VMs within the set, enhancing your application's reliability and uptime. The ability to deploy VMs swiftly across multiple servers is a core benefit of cloud infrastructure. Azure takes care of the distribution process, placing each VM across different servers and network components to bolster fault tolerance and service continuity.

Although deploying VMs across multiple servers might seem time-intensive, Azure’s infrastructure is optimized for rapid provisioning, often enabling VM deployment within minutes, which allows for swift scaling as demand fluctuates. Billing is based on the number of VMs running, regardless of deployment speed, so costs depend on the quantity of active instances rather than the time it takes to deploy them.

Please refer to this for detailed information on Availability sets https://learn.microsoft.com/en-us/azure/virtual-machines/availability-set-overview

If you have any further queries, please do let us know. If the answer is helpful, please click "Accept Answer" and "Upvote it" as it can be helpful to others in the community.
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Marouf Ali 270 Reputation points

2024-11-05T18:17:23.01+00:00

In Azure, are VM instances created by Azure portal, CLI, Bash etc.?
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More clarity on difference between VM and VM instances and Availability Sets (AS)

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