How to manage Application version for VM 39 s in Azure Autoscaling group

Question

I am running an application with autoscaled Azure VM. Let's suppose the current version of application is 1.0 is being served by 4 VM's as per the current load on application. Now, if I have a patch update and release a new version of application,i.e 2.0, then how will this new version of application updated to the currently VM's running? If load increases, and new VM gets started, they all will be having this new version of application 2.0, but the previously running 4 VM's, will they have this new version of application? And if yes, how? Can anyone solve my query?

Thanks

Answer 1

First of all, You have to launch Azure VMSS from ARM Template which will be having Custom Image as Source Image instead of Image from Marketplace. If you want to update application on VMs, again create a Custom image of VM having updated application and then update this new VM in VMSS with Powershell. Azure VMSS then automatically update all VMs in Scale Set with updated Image. Below is the code for Updating existing VMSS with new Custom Image.

  $rgname = "myrg"
    $vmssname = "myvmss"
    # get the VMSS model
    $vmss = Get-AzureRmVmss -ResourceGroupName $rgname -VMScaleSetName $vmssname
    # set the new version in the model data
    $vmss.virtualMachineProfile.storageProfile.imageReference.id = $newImageReference
    # update the virtual machine scale set model
    Update-AzureRmVmss -ResourceGroupName $rgname -Name $vmssname -VirtualMachineScaleSet $vmss
    # now start updating instances
    Update-AzureRmVmssInstance -ResourceGroupName $rgname -VMScaleSetName $vmssname -InstanceId $instanceId
I hope this will work for you.