Looking for a PowerShell script to retrieve and display the average CPU usage metrics for a specific Azure VM through the Azure Monitor REST API?

Question

Looking for a PowerShell script  to retrieve and display the average CPU usage metrics for a specific Azure VM through the Azure Monitor REST API?  

Answer 1

Try the following:

$subscriptionId = "<your-subscription-id>"
$resourceGroup = "<your-resource-group>"
$vmName = "<your-vm-name>"
$tenantId = "<your-tenant-id>"
$clientId = "<your-app-client-id>"       
$clientSecret = "<your-app-client-secret>" 

# Authenticate with Azure AD to get a token for Azure Monitor (resource = https://management.azure.com/)
$body = @{
    grant_type    = "client_credentials"
    client_id     = $clientId
    client_secret = $clientSecret
    scope         = "https://management.azure.com/.default"
}

$tokenResponse = Invoke-RestMethod -Method Post -Uri "https://login.microsoftonline.com/$tenantId/oauth2/v2.0/token" -Body $body
$accessToken = $tokenResponse.access_token

$resourceId = "/subscriptions/$subscriptionId/resourceGroups/$resourceGroup/providers/Microsoft.Compute/virtualMachines/$vmName"

$endTime = (Get-Date).ToUniversalTime().ToString("o")      # current UTC time
$startTime = (Get-Date).AddHours(-1).ToUniversalTime().ToString("o")  # last 1 hour

$uri = "https://management.azure.com$resourceId/providers/microsoft.insights/metrics?metricnames=Percentage%20CPU&timespan=$startTime/$endTime&aggregation=Average&api-version=2018-01-01"

$response = Invoke-RestMethod -Method Get -Uri $uri -Headers @{Authorization = "Bearer $accessToken"}

$metric = $response.value

if ($metric.timeseries.values) {
    Write-Host "Average CPU usage for VM '$vmName' in the last hour:"
    foreach ($point in $metric.timeseries.values) {
        if ($point.average) {
            Write-Host ("Time: {0}, CPU: {1}%" -f $point.timeStamp, [math]::Round($point.average,2))
        }
    }
} else {
    Write-Host "No CPU metric data found for the specified time range."
}

Authentication uses a service principal (clientId, clientSecret, tenantId). You must grant it Monitoring Reader access on the VM or subscription. Time range is set to the most recent 1 hour (timespan=$start/$end), but you can adjust it (e.g., AddMinutes(-30) for last 30 min).

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hth

Marcin

Answer 2

Hi kushal M

Please try with the below script and let us know the results:

# Variables - Replace with your details
$subscriptionId = "<YourSubscriptionId>"
$resourceGroup  = "<YourResourceGroupName>"
$vmName         = "<YourVMName>"
$metricName     = "Percentage CPU"
$apiVersion     = "2018-01-01"
# Time Range - Last 1 hour (Local Time)
$localEndTime   = Get-Date
$localStartTime = $localEndTime.AddHours(-1)
# Convert to UTC for API
$startTime = $localStartTime.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
$endTime   = $localEndTime.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
# Build Resource ID
$resourceId = "/subscriptions/$subscriptionId/resourceGroups/$resourceGroup/providers/Microsoft.Compute/virtualMachines/$vmName"
# Build REST API URI
$uri = "https://management.azure.com$resourceId/providers/microsoft.insights/metrics" +
       "?metricnames=$metricName" +
       "&timespan=$startTime/$endTime" +
       "&interval=PT5M" +
       "&api-version=$apiVersion"
# Get Access Token (requires Connect-AzAccount first)
$token = (Get-AzAccessToken -ResourceUrl "https://management.azure.com").Token
# Call Azure Monitor REST API
$response = Invoke-RestMethod -Method Get -Uri $uri -Headers @{Authorization = "Bearer $token"}
# Output CPU Metrics in Local Time (timestamp + average value)
$response.value.timeseries.data | ForEach-Object {
    [PSCustomObject]@{
        TimeStampLocal = ([datetime]$_."timeStamp").ToLocalTime()
        AverageCPU     = $_.average
    }
}

Please let me know if you face any challenge here, I can help you to resolve this issue further

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