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Azure Development Environment - Control when an Azure VM runs

Azure Development Environment Series:
In the last post we talk about how we can reduce the cost of Azure development environment of a small team by using an Azure VM to store all the databases that are needed by developers.
In this post we will see how we can optimize the cost of this Azure VM, by running it only when developers are active.

Context
Usually the development team works from 08:00 AM to 07:00 PM. Don't imagine that they stay for 11 hours at work. We have colleagues that comes at 08:00 AM and leave at 04:30 PM, others are coming at 10:00 AM and will stay until 07:00 PM.
Based on this information we observe that between 07:00 PM to 08:00 AM nobody is working. This means that the Azure VM is not required to run in this time interval.
There are 12h (plus 1h buffer) when nobody is working, when we could stop our VM. This means that we can reduce the costs for this service with 50%. At 07:00 PM we could shut down the VM and at 07:30 AM to start the VM again.

Manual
One solution is to talk with the team and the last person that leave the office should shut down the VM and in the morning the first guy that arrives at the office should start the VM. It will work, but why we should do this manually.

Azure Dev-Test Labs
A clean and nice solution for our problem is Azure Dev-Test Labs. This allow us to specify a time when the VM should shut down automatically. This can be done by defining a policy related to that specific VM (https://azure.microsoft.com/en-us/documentation/articles/devtest-lab-set-lab-policy/#set-auto-shutdown). Unfortunately, it doesn't allow us to start the VM automatically. In the morning we will still need somebody to start the VM.
  

Azure Automation
Another approach to automate this tasks is to use Azure Automation. This service enable us to run any kind of power-shell script directly from Azure. On top of this, we can specify when a task to be run.
We need to create two different runbooks. One that will run every morning and will start the VM and another in the evening that will shut down the Azure VM. 
To be able to access and control your subscription, you will need to add your credentials to the Azure Automation. The most simple way is to create a new Automation account and use your certificate for credentials. 
Once you done this, you can create the runbook for starting the VM. Don't forget to link the new runbook to the automation account that you created a step before. After this, you can add the power-shell script that start the VM (script can be found at the end of the post). 
The last step is to link the runbook to scheduler (a new one or to an existing one). This can be done from the Schedule tab of the runbook.

A scheduler can run only one time (at a time specific by us), hourly or daily. In the last two cases we can specify recurrence time (hours/days) and an expiration time. We cannot specify the day of the week when we want our runbook to run, but from the script we can check if is working day or not (see in the scripts).
A nice feature of Azure Automation is the price. First 500 minutes are free. In our case, the start operation takes around 10 minutes and the stop operation takes around 5 minutes. It means that we are consuming 450 minutes. Don't bother for price per minute because is very cheap -  0.0017e per minute (0.102e per hour). 

Conclusion
We identify that we need an Azure VM that is used by development team only only for 12h per day. We looked at 3 different ways to control when the Azure VM should run (manual, Azure Dev-Test Labs, Azure Automation). In this moment Azure Automation is the one that offers us all the capabilities that we need to automate this with minimal effort.


Start the VM:
workflow start-devsql-vm
{ 
    Param (  
        [parameter(Mandatory=$true)] 
        [String] 
        $VirtualMachineName,
        
        [parameter(Mandatory=$true)] 
        [String]
        $ResourceGroupName 
    )  
    
    $day = (Get-Date).DayOfWeek
    if ($day -eq 'Saturday' -or $day -eq 'Sunday'){
        exit
    }
        
    $SubscriptionName = Get-AutomationVariable -Name "SubscriptionName" 
    $SubscriptionId = Get-AutomationVariable -Name "SubscriptionID" 
    $CertificateThumbprint = Get-AutomationVariable -Name "CertificateThumbprint" 
    
    $TenantId = Get-AutomationVariable -Name "TenantId"
  $CertificateThumbprint = Get-AutomationVariable -Name "CertificateThumbprint"
    $ADApplicationId = Get-AutomationVariable -Name "ADApplicationId"
    
    $certificateName = Get-AutomationVariable -Name "CertificateName" 
    $certificate = Get-AutomationCertificate -Name $certificateName  
    
    # Set subscription profile
    Set-AzureSubscription -SubscriptionName $SubscriptionName -SubscriptionId $SubscriptionId -Certificate $certificate

    # Select subscription as the current context
    Select-AzureSubscription -SubscriptionName $SubscriptionName
    
    # Login to Azure Resource Manager
    Add-AzureRmAccount -TenantId $TenantId -ServicePrincipal -CertificateThumbprint $CertificateThumbprint -ApplicationId $ADApplicationId  
    
    $vm =  Get-AzureRmVM -Name $VirtualMachineName -ResourceGroupName $ResourceGroupName -Status  
    
    # Starting the virtual machine  
    Start-AzureRmVM -Name $Virt$VirtualMachineName -ResourceGroupName $ResourceGroupName 
}

Stop the VM:
workflow stop-devsql-vm
{ 
    Param (  
        [parameter(Mandatory=$true)] 
        [String] 
        $VirtualMachineName,
        
        [parameter(Mandatory=$true)] 
        [String]
        $ResourceGroupName 
    )  
    
    $day = (Get-Date).DayOfWeek
    if ($day -eq 'Saturday' -or $day -eq 'Sunday'){
        exit
    }
        
    $SubscriptionName = Get-AutomationVariable -Name "SubscriptionName" 
    $SubscriptionId = Get-AutomationVariable -Name "SubscriptionID" 
    $CertificateThumbprint = Get-AutomationVariable -Name "CertificateThumbprint" 
    
    $TenantId = Get-AutomationVariable -Name "TenantId"
  $CertificateThumbprint = Get-AutomationVariable -Name "CertificateThumbprint"
    $ADApplicationId = Get-AutomationVariable -Name "ADApplicationId"
    
    $certificateName = Get-AutomationVariable -Name "CertificateName" 
    $certificate = Get-AutomationCertificate -Name $certificateName  
    
    # Set subscription profile
    Set-AzureSubscription -SubscriptionName $SubscriptionName -SubscriptionId $SubscriptionId -Certificate $certificate

    # Select subscription as the current context
    Select-AzureSubscription -SubscriptionName $SubscriptionName
    
    # Login to Azure Resource Manager
    Add-AzureRmAccount -TenantId $TenantId -ServicePrincipal -CertificateThumbprint $CertificateThumbprint -ApplicationId $ADApplicationId  
    
    $vm =  Get-AzureRmVM -Name $VirtualMachineName -ResourceGroupName $ResourceGroupName -Status  
    
    # Stopping the virtual machine  
    Stop-AzureRmVM -Name $Virt$VirtualMachineName -ResourceGroupName $ResourceGroupName -Force
}

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