Converting existing VM deployment ARM templates to use Managed Disks

by | Feb 26, 2017

In my last blog post, I talked about why we should stop using regular storage accounts for our IaaS VMs and why should we use Managed Disks. In today’s blog post I will talk about how you can modify your existing ARM templates that deploy your VMS to use Managed Disks from now on.

Let’s take a look at a regular storage account based ARM Template:

## Resource block: 

 "resources": [
    {
      "type": "Microsoft.Storage/storageAccounts",
      "name": "[variables('storageAccountName')]",
      "apiVersion": "2015-06-15",
      "location": "[resourceGroup().location]",
      "properties": {
        "accountType": "[variables('storageAccountType')]"
      }
    },

## VM Storage Block:

        "storageProfile": {
          "imageReference": {
            "publisher": "[variables('imagePublisher')]",
            "offer": "[variables('imageOffer')]",
            "sku": "[variables('sku')]",
            "version": "latest"
          },
          "osDisk": {
            "name": "osdisk",
            "vhd": {
              "uri": "[concat(reference(concat('Microsoft.Storage/storageAccounts/', variables('storageAccountName')), '2015-06-15').primaryEndpoints.blob, variables('vmStorageAccountContainerName'),'/',variables('OSDiskName'),'.vhd')]"
            },
            "caching": "ReadWrite",
            "createOption": "FromImage"
          },
          "dataDisks": [
            {
              "name": "datadisk1",
              "diskSizeGB": "100",
              "lun": 0,
              "vhd": {
                "uri": "[concat(reference(concat('Microsoft.Storage/storageAccounts/', variables('storageAccountName')), '2015-06-15').primaryEndpoints.blob, variables('vmStorageAccountContainerName'),'/',variables('dataDisk1VhdName'),'.vhd')]"
              },
              "createOption": "Empty"
            },

We have a resources block where we specify a storage account, and we use that resource to create an OS Disk and a Data Disk for the particular VM.

If we want to add more disks then we copy paste the what’s between the dataDisks array a couple of times, modify the LUN and name and we’re happy.

Converting the template to a managed disk format is pretty easy. You first need to reference in the template the API Compute (do note that we’re not modifying storage API) version 2016-04-30-preview or a later version (never use -preview in your production templates!)

You change the storage profile to reference managed disks as shown the code snip below:

 "storageProfile": {
          "imageReference": {
            "publisher": "[variables('imagePublisher')]",
            "offer": "[variables('imageOffer')]",
            "sku": "[variables('sku')]",
            "version": "latest"
          },
            "osDisk": {
                "createOption": "FromImage"
            },
            "dataDisks": [
                {
                    "diskSizeGB": 1023,
                    "lun": 0,
                    "createOption": "Empty"
                }
            ]

Hard? I don’t think so, MS made it very easy to convert existing templates to use Managed Disks. You basically remove some code from the template 🙂

This sample is for single VMs;

If you have multiple VMs in an Availability set, you need to add a “managed” property to the Availability Set block like shown below:

    {
      "apiVersion": "2016-04-30-preview",
      "type": "Microsoft.Compute/availabilitySets",
      "name": "[variables('availabilitySetName')]",
      "location": "[resourceGroup().location]",
      "properties": {
        "platformFaultDomainCount": "2",
        "platformUpdateDomainCount": "2",
        "managed": "true"
      }

Hope this was usefull, if you have any comments, write them down below 🙂

Have a good one!

ARM Template – Creating NGINX Webfarm with Custom Script Extension

by | Sep 25, 2016

A friend of mine recently started working with Azure and loved it once he got the hang of it. I encouraged him to start using PowerShell to automate various Azure operations but it didn’t quite stick with him on the first try. He started automating Azure operations using the Azure CLI and while it’s not a bad tool, it’s quite lacking in features compared to PowerShell and I’m pretty sure that it will not be maintained much longer since Microsoft open sourced PowerShell and gave the Linux / Mac community a taste. The funny part of this story is that he’s a Windows user, uses Windows 10 and yet he’s still using Azure CLI.

Where am I going with this? While giving him some tips on how to deploy some production / staging environments in Azure, I saw how he was automating resource creation in Azure using the CLI. He basically created a golden image in a storage account and with 35 lines of Azure CLI code, he was provisioning the environments. That made me cringe and motivated me to teach him how to do it using ARM templates and custom scripts.
(more…)

ARM Templates for creating custom image VMs in Azure

by | Mar 26, 2016

If you worked with Azure for a long time, you know that when you wanted to upload your own custom VM image to Azure, it was an easy thing. You prepared the VM, you sent it to Azure using PowerShell and after that you tagged it as an OS disk and that was it. Well that was the old way using the Azure Service Manager which I must say it was quite an easy procedure. With Azure Resource Manager, things changed quite a bit. You still have the possibility of uploading the VHDs to Azure but the deployment requires a little more work. You have to write code for that deployment to happen, be it in PowerShell or JSON. In this blog post I’m going to give you two ARM templates which you can use to deploy your freshly uploaded VHDs.
(more…)

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