Virtual machine scale set extension support on Service Fabric managed cluster node type(s)

Grein
08/22/2024

Each node type in a Service Fabric managed cluster is backed by a virtual machine scale set. This enables you to add virtual machine scale set extensions to your Service Fabric managed cluster node types. Extensions are small applications that provide post-deployment configuration and automation on Azure VMs. The Azure platform hosts many extensions covering VM configuration, monitoring, security, and utility applications. Publishers take an application, wrap it into an extension, and simplify the installation. All you need to do is provide mandatory parameters.

Add a virtual machine scale set extension

You can add a virtual machine scale set extension to a Service Fabric managed cluster node type using the Add-AzServiceFabricManagedNodeTypeVMExtension PowerShell command.

Alternately, you can add a virtual machine scale set extension on a Service Fabric managed cluster node type in your Azure Resource Manager template, for example:

{
  "type": "Microsoft.ServiceFabric/managedclusters/nodetypes",
  "apiVersion": "[variables('sfApiVersion')]",
  "name": "[concat(parameters('clusterName'), '/', parameters('nodeTypeName'))]",
  "dependsOn": [
    "[concat('Microsoft.ServiceFabric/managedclusters/', parameters('clusterName'))]"
  ],
  "location": "[resourceGroup().location]",
  "properties": {
    "isPrimary": true,
    ...
    "vmExtensions": [
      {
        "name": "KvExtension",
        "properties": {
          "publisher": "Microsoft.Azure.KeyVault",
          "type": "KeyVaultForWindows",
          "typeHandlerVersion": "3.0",
          "autoUpgradeMinorVersion": true,
          "settings": {
            "secretsManagementSettings": {
              "observedCertificates": [
                ...
              ]
            }
          }
        }
      }
    ]
  }
}

For more information on configuring Service Fabric managed cluster node types, see managed cluster node type.

How to provision before Service Fabric runtime

To provision extensions before the Service Fabric runtime starts, you can use the setupOrder parameter with the value BeforeSFRuntime in the extension properties for each extension as needed. This allows you to set up the environment and dependencies before the runtime and applications begin running on the node. See the example below for clarification:

Note

It's essential to note that if an extension marked with BeforeSFRuntime fails, it will prevent the Service Fabric runtime from starting. Consequently, the node will be down from the Service Fabric perspective. Therefore, it is crucial to maintain these extensions with correct configurations and promptly address any issues that may arise to ensure the health of nodes within the cluster.

Requirements

Use Service Fabric API version 2023-09-01-preview or later.

ARM Template example:

{
  "type": "Microsoft.ServiceFabric/managedclusters/nodetypes",
  "apiVersion": "2023-09-01-preview",
  "name": "[concat(parameters('clusterName'), '/', parameters('nodeTypeName'))]",
  "properties": {
    "isPrimary": true,
    ...
    "vmExtensions": [
        {
            "name": "KvExtension",
            "properties": {
                "setupOrder": [
                    "BeforeSFRuntime"
                ],
                "provisionAfterExtensions" [ "GenevaMonitoringExtension" ],
                "publisher": "Microsoft.Azure.KeyVault",
                "type": "KeyVaultForWindows",
                "typeHandlerVersion": "3.0",
                "autoUpgradeMinorVersion": true,
                "settings": {
                "secretsManagementSettings": {
                  "observedCertificates": [
                    ...
                  ]
                }
              }
            }
        },
        {
          "name": "GenevaMonitoringExtension",
          "properties": {
              "setupOrder": [
                    "BeforeSFRuntime"
                ],
              "autoUpgradeMinorVersion": true,
              "enableAutomaticUpgrade": true,
              "publisher": "Microsoft.Azure.Geneva",
              "type": "GenevaMonitoring",
              "typeHandlerVersion": "2.40",
              "settings": {
                "configurations": [
                  {
                    "ServiceArguments": {
                      ...
                    },
                    "UserArguments": {
                      ...
                    }
                  }
                ]
              }
          }
      }
    ]
  }
}

Note

Special handling for AzureDiskEncryption (ADE) extension: ADE needs to run before the Service Fabric runtime to ensures that the disk is decrypted after a reimage operations, allowing the Service Fabric runtime to start using it. Even if the extension is not explicitly marked with BeforeSFRuntime, it will run before the runtime. But note that enabling encryption at host is recommended over using ADE extension. For detailed instructions, refer to Enable encryption at host.

Next steps

To learn more about Service Fabric managed clusters, see:

Service Fabric managed clusters frequently asked questions

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