Powershell invoke-restmethod variable in url - azure

Question

I am new to powershell, and I am trying to create a simple script that will allow me to turn on several Azure VMs using the invoke-restmethod.
My code works when instead of using a variable I directly write the VM name into the url, but I want to use a variable, since eventually this must work for more than one VM.
Relevant part of code:
$body = #{
"$virtualMachines" = "VM1"
} | ConvertTo=Json
$url= "https://management.azure.com/subscriptions/mySubscriptionId/resourceGroups/myResourceGroupName/providers/Microsoft.DevTestLab/labs/myLabName/virtualmachines/" + $virtualMachines + "/start?api-version=2018-09-15"
$response = Invoke-RestMethod -uri $url -Method 'POST' -Headers $headers -Body $body
$response | ConvertTo-Json

Answer 1

If you had a number of VMs, you could put them all into a PowerShell variable like this, an array of strings.
$VMs = "myVm1", "myVm2", "myVm3"
PowerShell has a number of flow control statements, the one you want to use is ForEach, which will step through an array one at a time. We just modify the way you're setting up the URL to be friendlier and easier to read and this should work just fine.
$baseUrl = "https://management.azure.com/subscriptions/mySubscriptionId/resourceGroups/myResourceGroupName/providers/Microsoft.DevTestLab/labs/myLabName/virtualmachines/"
ForEach ($vm in $VMs){
$url = $baseurl + $vm + "/start?api-version=2018-09-15"
Write-host "About to start [$Vm]"
$response = Invoke-RestMethod -uri $url -Method 'POST' -Headers $headers
$response | ConvertTo-Json
}
I checked the API documentation for the start? REST API endpoint, and it doesn't look like you need the -Body parameter for this endpoint.