Including option to use VMSS Flex

workload/arm/brownfield/deployNewSessionHostsToHostPools.json

@@ -5,7 +5,7 @@
     "_generator": {
       "name": "bicep",
       "version": "0.30.23.60470",
-      "templateHash": "14713858361202530562"
+      "templateHash": "2465926344295153346"
     }
   },
   "parameters": {
@@ -1611,9 +1611,7 @@
           "encryptionAtHost": {
             "value": "[parameters('diskZeroTrust')]"
           },
-          "virtualMachineScaleSetResourceId": {
-            "value": "[parameters('virtualMachineScaleSetResourceId')]"
-          },
+          "virtualMachineScaleSetResourceId": "[if(not(empty(parameters('virtualMachineScaleSetResourceId'))), createObject('value', parameters('virtualMachineScaleSetResourceId')), createObject('value', ''))]",
           "osType": {
             "value": "Windows"
           },

workload/bicep/brownfield/newSessionHosts/deploy.bicep

@@ -317,7 +317,7 @@ module sessionHosts '../../../../avm/1.0.0/res/compute/virtual-machine/main.bice
       systemAssigned: true
   }: null
     encryptionAtHost: diskZeroTrust
-    virtualMachineScaleSetResourceId: virtualMachineScaleSetResourceId
+    virtualMachineScaleSetResourceId: !empty(virtualMachineScaleSetResourceId) ? virtualMachineScaleSetResourceId : ''
     osType: 'Windows'
     licenseType: 'Windows_Client'
     vmSize: vmSize

workload/bicep/deploy-baseline.bicep

@@ -207,6 +207,9 @@ param availabilityZonesCompute bool = true
 @sys.description('When true, Zone Redundant Storage (ZRS) is used, when set to false, Locally Redundant Storage (LRS) is used. (Default: false)')
 param zoneRedundantStorage bool = false
 
+@sys.description('Deploys a VMSS Flex group and associates session hosts with it for availability purposes. (Default: true)')
+param deployVmssFlex bool = true
+
 @sys.description('Sets the number of fault domains for the availability set. (Default: 2)')
 param vmssFlatformFaultDomainCount int = 2
 
@@ -1441,7 +1444,7 @@ module msixAzureFilesStorage './modules/storageAzureFiles/deploy.bicep' = if (va
 }
 
 // VMSS Flex
-module vmScaleSetFlex './modules/avdSessionHosts/.bicep/vmScaleSet.bicep' =  if (avdDeploySessionHosts) {
+module vmScaleSetFlex './modules/avdSessionHosts/.bicep/vmScaleSet.bicep' =  if (avdDeploySessionHosts && deployVmssFlex) {
   name: 'AVD-VMSS-Flex-${time}'
   scope: resourceGroup('${avdWorkloadSubsId}', '${varComputeObjectsRgName}')
   params: {
@@ -1473,6 +1476,7 @@ module sessionHosts './modules/avdSessionHosts/deploy.bicep' = [
       createIntuneEnrollment: createIntuneEnrollment
       maxVmssFlexMembersCount: varMaxVmssFlexMembersCount
       vmssFlexNamePrefix: varVmssFlexNamePrefix
+      useVmssFlex: deployVmssFlex
       batchId: i - 1
       computeObjectsRgName: varComputeObjectsRgName
       count: i == varSessionHostBatchCount && varMaxSessionHostsDivisionRemainderValue > 0

workload/bicep/modules/avdSessionHosts/deploy.bicep

@@ -34,6 +34,9 @@ param subscriptionId string
 @sys.description('Quantity of session hosts to deploy.')
 param count int
 
+@sys.description('Associate VMs with VMSS Flex group.')
+param useVmssFlex bool
+
 @sys.description('Max VMs per availability set.')
 param maxVmssFlexMembersCount int
 
@@ -178,7 +181,7 @@ module sessionHosts '../../../../avm/1.0.0/res/compute/virtual-machine/main.bice
             systemAssigned: true
         }: null
         encryptionAtHost: encryptionAtHost
-        virtualMachineScaleSetResourceId: '/subscriptions/${subscriptionId}/resourceGroups/${computeObjectsRgName}/providers/Microsoft.Compute/virtualMachineScaleSets/${vmssFlexNamePrefix}-${padLeft(((1 + (i + countIndex) / maxVmssFlexMembersCount)), 3, '0')}'
+        virtualMachineScaleSetResourceId: useVmssFlex ? '/subscriptions/${subscriptionId}/resourceGroups/${computeObjectsRgName}/providers/Microsoft.Compute/virtualMachineScaleSets/${vmssFlexNamePrefix}-${padLeft(((1 + (i + countIndex) / maxVmssFlexMembersCount)), 3, '0')}': ''
         osType: 'Windows'
         licenseType: 'Windows_Client'
         vmSize: vmSize

workload/bicep/parameters/deploy-baseline-parameters-example.json

@@ -208,6 +208,9 @@
         },
         "deployGpuPolicies": {
             "value": false
+        },
+        "deployVmssFlex": {
+            "value": true
         }
     }
 }

workload/docs/deploy-baseline.md

@@ -37,7 +37,8 @@
   - **Deploy sessions hosts** - You can choose to not deploy session hosts just the Azure Virtual Desktop service objects.
   - **Session host region** - Provide the region to where you want to deploy the session hosts. This defaults to the Management Plane region but can be changed.
   - **Session hosts OU path (Optional)** - Provide OU where to locate session hosts, if not provided session hosts will be placed on the default (computers) OU. If left empty the computer account will be created in the default Computers OU. Example: OU=avd,DC=contoso,DC=com.
-  - **Availability zones** - If you deselect the checkbox, an Availability set will be created instead and session hosts will be created in the availability set. If you select the checkbox the accelerator  will distribute compute and storage resources across availability zones.
+  - **Availability zones** - If you deselect the checkbox, VMs will be deployed regionally and will be associated with a regional VMSS Flex (if VMSS is enabled). If you select the checkbox the accelerator  will distribute compute and storage resources across availability zones and will also associate the VMs with a VMSS Flex group created to use multiple availability zones.
+  - **VMSS Flex** - If you deselect the checkbox, no VMSS Flex will be created. If you select the checkbox, the accelerator will deploy a VMSS Flex and VMs will be associated with it.
   - **VM size** -  Select the SKU size for the session hosts.
   - **VM count** - Select the number of session hosts to deploy.
   - **OS disk type** - Select the OS Disk SKU type. Premium is recommended for performance and higher SLA.

workload/portal-ui/brownfield/portalUiNewSessionHosts.json

@@ -320,6 +320,7 @@
                                     "label": "Select VMSS Flex",
                                     "visible": true,
                                     "resourceType": "Microsoft.Compute/virtualMachineScaleSets",
+                                    "toolTip": "Deploy and associate session hosts with a Virtual Machine Scale Set (VMSS) with Flex orchestration to distribute session hosts across fault domains.",
                                     "constraints": {
                                         "required": false
                                     },

workload/portal-ui/portal-ui-baseline.json

@@ -572,7 +572,15 @@
                                     "visible": true,
                                     "label": "Availability zones",
                                     "defaultValue": true,
-                                    "toolTip": "Distribute compute resources across availability zones using multi zone VMSS Flex with 1 fault domain. If 'No' is selected then a VMSS Flex will be created to host the VMs at a regional level but distributing across multiple fault domains."
+                                    "toolTip": "Distribute compute resources across availability zones using multi zone VMSS Flex with 1 fault domain (when VMSS Flex is enabled). If 'No' is selected then a VMSS Flex will be created to host the VMs at a regional level but distributing across multiple fault domains."
+                                },
+                                {
+                                    "name": "sessionHostsAvailabilitySettingsVmss",
+                                    "type": "Microsoft.Common.CheckBox",
+                                    "visible": true,
+                                    "label": "VMSS Flex",
+                                    "defaultValue": true,
+                                    "toolTip": "Deploy and associate session hosts with a Virtual Machine Scale Set (VMSS) with Flex orchestration to distribute session hosts across fault domains."
                                 },
                                 {
                                     "name": "sessionHostsRegion",
@@ -2385,6 +2393,7 @@
                 "avdDeployScalingPlan": "[if(contains(steps('basics').resourceScope.location.name, 'china'), false, steps('managementPlane').managementPlaneHostPoolScaling.scalingPlan)]",
                 "avdEnterpriseAppObjectId": "[first(map(steps('managementPlane').managementPlaneHostPoolScaling.avdEnterpriseApplication.value, (item) => item.id))]",
                 "availabilityZonesCompute": "[if(equals(steps('sessionHosts').deploySessionHosts, true), steps('sessionHosts').sessionHostsRegionSection.sessionHostsAvailabilitySettings, false)]",
+                "deployVmssFlex": "[if(equals(steps('sessionHosts').deploySessionHosts, true), steps('sessionHosts').sessionHostsRegionSection.sessionHostsAvailabilitySettingsVmss, false)]",
                 "zoneRedundantStorage": "[if(or(steps('storage').storageFslogix.fslogixDeployment, steps('storage').storageMsix.msixDeployment), steps('storage').storageGeneralSettings.storageGeneralSettingsZoneRedundancy, false)]",
                 "avdDeploySessionHostsCount": "[if(equals(steps('sessionHosts').deploySessionHosts, true), steps('sessionHosts').sessionHostsSettingsSection.sessionHostsCount, 1)]",
                 "useSharedImage": "[if(equals(steps('sessionHosts').deploySessionHosts, true), steps('sessionHosts').sessionHostsOsSection.sessionHostsImageSource, false)]",