Why VMs provide compute flexibility in Azure - Why It Works

Introduction

Virtual Machines (VMs) let you run many different software programs on one physical computer. They give you the power to change how much computing power you use, so you only pay for what you need.

When you want to run multiple different applications on one physical server without them interfering with each other

When you need to quickly add more computing power to handle more users or data

When you want to test new software safely without affecting your main system

When you want to move your applications easily between different physical servers

When you want to save money by using only the computing resources you need at any time

Commands

This command creates a new virtual machine in Azure with a small size to start. It sets up a user and SSH keys for secure access.

Terminal

az vm create --resource-group example-group --name example-vm --image UbuntuLTS --size Standard_B1s --admin-username azureuser --generate-ssh-keys

Expected Output

{

  "fqdns": "",

  "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/example-group/providers/Microsoft.Compute/virtualMachines/example-vm",

  "location": "eastus",

  "name": "example-vm",

  "powerState": "VM running",

  "resourceGroup": "example-group",

  "zones": ""

}

→

--size - Sets the VM size which controls compute power

→

--image - Chooses the operating system for the VM

→

--generate-ssh-keys - Creates SSH keys for secure login

This command changes the VM to a bigger size with more CPU and memory to handle more work.

Terminal

az vm resize --resource-group example-group --name example-vm --size Standard_B2s

Expected Output

Succeeded

→

--size - Specifies the new VM size to increase compute resources

This command checks the current size of the VM to confirm the resize worked.

Terminal

az vm show --resource-group example-group --name example-vm --query "hardwareProfile.vmSize" -o tsv

Expected Output

Standard_B2s

Key Concept

If you remember nothing else from this pattern, remember: VMs let you quickly change computing power by resizing, giving you flexible control over resources.

Common Mistakes

Trying to resize a VM while it is running without stopping it first

Some VM sizes require the VM to be stopped before resizing, so the command will fail or cause errors

Stop the VM using 'az vm deallocate' before resizing, then start it again after resizing

Choosing a VM size that does not exist in the selected region

Azure does not offer all VM sizes in every region, so the creation or resize will fail

Check available VM sizes in the region with 'az vm list-sizes --location eastus' before creating or resizing

Summary

Create a VM with a chosen size to start with the right amount of compute power.

Resize the VM to increase or decrease compute resources as your needs change.

Verify the VM size after resizing to ensure the change was successful.