Right-sizing resources in Azure - Commands & Configuration

Introduction

Right-sizing resources means choosing the best size for your cloud services so you don't pay too much or have too little power. It helps balance cost and performance by matching resources to what your app really needs.

When your app is running slowly because it has too little CPU or memory.

When your cloud bill is higher than expected and you want to save money.

When you want to adjust resources after testing your app's real usage.

When you scale your app and need to pick the right size for new servers.

When you want to avoid wasting resources that are not being used.

Commands

This command lists all available virtual machine sizes in the East US region so you can see your options for right-sizing.

Terminal

az vm list-sizes --location eastus

Expected Output

Name             NumberOfCores  MemoryInMB  MaxDataDiskCount

Standard_B1s     1              1024        2

Standard_B2s     2              4096        4

Standard_D2s_v3  2              8192        8

Standard_F4s     4              8192        16

→

--location - Specifies the Azure region to list VM sizes for

This command checks the CPU usage of your virtual machine over the last hour to understand if the current size fits your needs.

Terminal

az monitor metrics list --resource /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/myResourceGroup/providers/Microsoft.Compute/virtualMachines/myVM --metric CPUPercentage --interval PT1H

Expected Output

{

  "value": [

    {

      "timeseries": [

        {

          "data": [

            {"timeStamp": "2024-06-01T10:00:00Z", "average": 15.2},

            {"timeStamp": "2024-06-01T11:00:00Z", "average": 18.7}

          ]

        }

      ]

    }

  ]

}

→

--resource - Specifies the resource to get metrics for

→

--metric - Specifies which metric to retrieve

→

--interval - Sets the time range for the metrics

This command changes the size of your virtual machine to Standard_B2s, which has 2 CPUs and 4 GB memory, to better match your app's needs.

Terminal

az vm resize --resource-group myResourceGroup --name myVM --size Standard_B2s

Expected Output

Succeeded

→

--resource-group - Specifies the resource group of the VM

→

--name - Specifies the name of the VM to resize

→

--size - Specifies the new VM size

This command verifies the current size of your virtual machine after resizing to confirm the change.

Terminal

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

Expected Output

Standard_B2s

→

--query - Filters output to show only the VM size

→

-o - Outputs the result as plain text

Key Concept

If you remember nothing else from this pattern, remember: monitor your resource usage first, then pick a size that matches your real needs to save money and keep performance smooth.

Common Mistakes

Resizing a VM without checking current usage metrics first.

You might pick a size too small or too large, causing poor performance or wasted cost.

Always check CPU, memory, and other metrics before resizing to understand actual needs.

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

Some VM sizes require the VM to be stopped before resizing, or the command will fail.

Stop the VM using 'az vm stop' before resizing if required by the size change.

Ignoring the region when listing VM sizes.

Available VM sizes differ by region, so you might pick a size not available in your location.

Always specify the correct region with --location when listing sizes.

Summary

List available VM sizes in your Azure region to know your options.

Check your VM's CPU and memory usage metrics to understand resource needs.

Resize your VM to a size that fits your app's real usage to optimize cost and performance.

Verify the VM size after resizing to confirm the change.

Practice

1. What does right-sizing mean in Azure cloud resource management?

easy

A. Buying the largest possible resources to avoid any performance issues

B. Choosing the best size for your cloud resources to save cost and improve performance

C. Using only free-tier resources regardless of workload needs

D. Deleting unused resources without checking their usage

Solution

1. Step 1: Understand the term 'right-sizing'

   Right-sizing means selecting the most appropriate size of cloud resources based on actual workload needs.

2. Step 2: Identify the benefits of right-sizing

   It helps save money by avoiding over-provisioning and improves performance by matching resources to demand.

3. Final Answer:

   Choosing the best size for your cloud resources to save cost and improve performance -> Option B

4. Quick Check:

   Right-sizing = Best size choice [OK]

Hint: Right-sizing means matching resource size to workload needs [OK]

Common Mistakes:

• Thinking bigger is always better
• Ignoring cost savings
• Confusing right-sizing with deleting resources

2. Which Azure CLI command sequence correctly resizes a virtual machine named myVM to size Standard_DS2_v2?

easy

A. az vm stop --name myVM && az vm resize --name myVM --size Standard_DS2_v2 && az vm start --name myVM

B. az vm resize --name myVM --size Standard_DS2_v2 && az vm stop --name myVM && az vm start --name myVM

C. az vm start --name myVM && az vm resize --name myVM --size Standard_DS2_v2 && az vm stop --name myVM

D. az vm start --name myVM && az vm stop --name myVM && az vm resize --name myVM --size Standard_DS2_v2

Solution

1. Step 1: Stop the VM before resizing

   Azure requires the VM to be stopped before changing its size to avoid errors.

2. Step 2: Resize and then start the VM

   After stopping, resize the VM, then start it again to apply changes.

3. Final Answer:

   az vm stop --name myVM && az vm resize --name myVM --size Standard_DS2_v2 && az vm start --name myVM -> Option A

4. Quick Check:

   Stop, resize, start = correct order [OK]

Hint: Always stop VM before resizing, then start it [OK]

Common Mistakes:

• Trying to resize while VM is running
• Starting VM before resizing
• Wrong command order causing errors

3. Given this Azure CLI snippet, what will be the output status of the VM after execution?

az vm stop --name testVM && az vm resize --name testVM --size Standard_B1s && az vm start --name testVM && az vm show --name testVM --query "powerState" -o tsv

medium

A. VM will be running

B. VM will be stopped

C. VM will be deallocated

D. Command will fail due to wrong order

Solution

1. Step 1: Analyze command sequence

   The VM is stopped, resized, then started, and finally its power state is queried.

2. Step 2: Determine VM state after commands

   Since the VM is started before querying, the power state will show as running.

3. Final Answer:

   VM will be running -> Option A

4. Quick Check:

   Stop, resize, start, then check = running [OK]

Hint: Last command starts VM before checking state [OK]

Common Mistakes:

• Assuming VM stays stopped after start command
• Confusing deallocated with stopped
• Ignoring command order effects

4. You tried to resize an Azure VM using:

az vm resize --name myVM --size Standard_DS3_v2

but got an error. What is the most likely cause?

medium

A. You need to start the VM before resizing

B. The VM name is incorrect

C. The size Standard_DS3_v2 does not exist

D. The VM is currently running and must be stopped before resizing

Solution

1. Step 1: Understand Azure VM resize requirements

   Azure requires the VM to be stopped before resizing to avoid conflicts.

2. Step 2: Identify common error causes

   If the VM is running, resize commands fail with an error prompting to stop the VM first.

3. Final Answer:

   The VM is currently running and must be stopped before resizing -> Option D

4. Quick Check:

   VM must be stopped before resize [OK]

Hint: Stop VM before resizing to avoid errors [OK]

Common Mistakes:

• Trying to resize running VM
• Assuming VM name typo without checking
• Believing VM must be started before resize

5. You have a VM running with size Standard_DS4_v2 but your monitoring shows only 20% CPU usage consistently. Which is the best right-sizing approach to reduce costs without impacting performance?

hard

A. Resize the VM to Standard_DS1_v2 while it is running

B. Keep the current size since resizing may cause downtime

C. Resize the VM to Standard_DS2_v2 after stopping it, then start it again

D. Delete the VM and create a new smaller VM

Solution

1. Step 1: Analyze CPU usage and sizing

   Low CPU usage (20%) suggests the VM is over-provisioned and can be downsized safely.

2. Step 2: Choose a smaller size and follow correct resize steps

   Resizing to Standard_DS2_v2 reduces cost and maintains performance. Stop VM before resizing, then start it.

3. Final Answer:

   Resize the VM to Standard_DS2_v2 after stopping it, then start it again -> Option C

4. Quick Check:

   Stop, resize smaller, start = cost saving [OK]

Hint: Downsize VM after stopping to save cost safely [OK]

Common Mistakes:

• Resizing while VM is running
• Ignoring low CPU usage signals
• Deleting VM unnecessarily