🤔 What is a virtual machine?
In its simplest form, a virtual machine, or VM, is a digitized version of a physical computer. Virtual machines can run programs and operating systems, store data, connect to networks, and do other computing functions. However, a VM uses entirely virtual resources instead of physical components.
VMs enable businesses to create isolated environments on host hardware that behave like separate machines. A more straightforward way to understand what a virtual machine is to think of it as a virtual computer within another computer. But instead of a physical computer like a server, laptop, or smartphone, a VM is defined by software.
How do virtual machines work?
Virtual machines use virtualization technology to create virtual hardware—or a virtual version of a computer on a physical machine. The physical machine on which the VMs run is called the host, and the VMs running on the host are called guests.
Each guest VM runs on an isolated partition on the host, completely separated from other guests. You can host multiple VMs on a single host machine, often a server, running on a software layer known as the hypervisor.
The hypervisor abstracts the host machine’s physical resources, such as compute, memory, or storage, into a pool that can be provisioned and dynamically allocated to guest VMs as needed, providing more flexibility and increasing overall efficiency.
💻 Azure VM Size and Series Naming Guide
Azure VMs come in different series, each designed for specific workloads. The name usually looks like: D2s_v3, where each part has a meaning.
| Series | Use Case | Example VM Size | Meaning of Name Parts |
|---|---|---|---|
| A | Entry-level testing/dev | A1, A2 | Basic CPU/memory, low cost |
| B | Burst workloads | B1s, B2ms | Cheap VMs that can "burst" CPU when needed |
| D | General purpose | D2s_v3 |
D = Gen purpose, 2 = vCPUs, s = SSD, v3 = version |
| E | Memory optimized | E4s_v5 |
E = More RAM per CPU, good for in-memory apps |
| F | Compute optimized | F8s_v2 |
F = High CPU-to-memory ratio |
| G | Memory and storage intensive | G5 | Large memory and storage for big databases |
| H | High-performance computing (HPC) | H16r | For scientific simulations, modeling, etc. |
| L | Storage optimized | L8s_v2 | High disk throughput for heavy I/O workloads |
| M | Massive memory (SAP, DBs) | M128ms | Very high memory, ideal for SAP HANA |
| N | GPU workloads (AI, ML) | NC6, ND40rs_v2 | For deep learning, graphics rendering, etc. |
Name structure breakdown
Here's a breakdown of a 'Standard_DC8ads_v5' size in the 'DCadsv5-series'
For more details refer Azure documentation: https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/overview
💳 Azure VM Billing Options
Azure offers flexible billing options to help you balance cost and usage. Here's a quick overview:
| Billing Option | Description | Best For |
|---|---|---|
| Pay-as-you-go | No commitment, pay hourly or per second. Start/stop anytime. | Short-term or unpredictable workloads |
| Reserved Instances | Commit to 1 or 3 years. Up to 70% cheaper than pay-as-you-go. VM size and region must stay the same. | Steady, long-term workloads |
| Spot Instances | Use unused Azure capacity at up to 90% discount. Can be evicted anytime (no guarantee). | Batch jobs, dev/test, non-critical tasks |
| Azure Savings Plans | Flexible commitment (e.g., $100/month) for 1–3 years. Applies discounts across matching VMs/services. | Dynamic workloads needing flexibility |
🧠 Example Comparison
| VM Type | Billing Option | Cost (est.) | Notes |
|---|---|---|---|
| D2s_v3 | Pay-as-you-go | ~$0.096/hour | Most expensive but most flexible |
| D2s_v3 | 1-Year Reserved | ~$0.065/hour | Save ~30% |
| D2s_v3 | 3-Year Reserved | ~$0.045/hour | Save ~50% |
| D2s_v3 | Spot | ~$0.02–0.03/hour | Cheapest but may stop anytime |
🔄 Key Tips
- Auto-shutdown unused VMs to save money.
- Mix and match billing options across your workloads.
- Use the Azure Pricing Calculator to estimate and compare.
🔗 Azure Pricing Calculator
Use the official tool: Azure Pricing Calculator to get an accurate estimate based on your needs.
👷♂️ Creating Linux Virtual Machine
Refer to the step-by-step guide in the official Azure documentation: Quickly create a Linux VM using the Azure portal
👨🏻💻 Creating Windows Virtual Machine
Refer to the step-by-step guide in the official Azure documentation: Quickstart: Create a Windows virtual machine in the Azure portal
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