Introduction to MaintenanceControl on Service Fabric managed clusters

Service Fabric managed clusters have multiple background operations that are necessary to the keep all the cluster updated, thus ensuring security and reliability. Even though these operations are critical, but executing in the background can result in the service replica to move to a different node. This failover results in undesired and unnecessary interruptions, if the maintenance operation executes during the peak business hours. With the support for MaintenanceControl in Service Fabric managed clusters, customers would be able to define a recurring (daily, weekly, monthly) and custom maintenance window for their SFMC cluster resource, as per their needs. All background maintenance operations will be allowed to execute only during this maintenance window. MaintenanceControl is applicable to these background operations:

• Automatic OS Upgrade
• Automatic extension upgrade
• Automatic SF runtime version updates
• Automatic cluster certificate update

Requirements:

• Maintenance window configuration needs to be defined only for the Service Fabric managed cluster resource
• The minimum supported window size is 5 hours

How does MaintenanceControl work for SFMC

• Customers need to define a maintenance configuration that contains the schedule and the recurrence rule for the maintenance window, by creating a maintenance configuration resource with the maintenance RP. More details
• With this maintenance configuration, an assignment resource is created to assign the maintenance configuration to the SFMC cluster resource.
• on the creation of the assignment resource, the maintenance RP notifies the ServiceFabric RP about the link and maintenance control is then enabled on the SFMC cluster. All background maintenance operations are blocked outside the maintenance window.
• Whenever the maintenance window is activated as per the schedule in the maintenance configuration, the maintenance RP notifies the ServiceFabric RP that activates the maintenance window on corresponding SFMC cluster. All background operations are allowed to execute during this window.

Example deployment

The following is a step by step process to set up a cluster with maintenance control. Download this sample, which contains all the required resources. Standard SKU Service Fabric managed cluster sample

1. Create resource group in a region:

   Connect-AzAccount -Environment AzureChinaCloud
   Select-AzSubscription -SubscriptionId $subscriptionid
   New-AzResourceGroup -Name $myresourcegroup -Location $location
   

2. Create cluster resource:

   Execute this command to deploy the cluster resource:

   $parameters = @{
   clusterName = $clusterName
   adminPassword = $VmAdminPassword
   clientCertificateThumbprint = $clientCertificateThumbprint
   }
   New-AzResourceGroupDeployment -Name "deploy_cluster" -ResourceGroupName $resourceGroupName -TemplateFile .\azuredeploy.json -TemplateParameterObject $parameters -Verbose
   

3. Configure maintenance control on the cluster using the following maintenance configuration:

This maintenance configuration defines a schedule for updates to happen everyday from 10PM PST for 5hours, starting 30-05-2023. More details about maintenance configuration

    "resources": [
        {
            "type": "Microsoft.Maintenance/maintenanceConfigurations",
            "apiVersion": "2022-07-01-preview",
            "name": "mc1",
            "location": "[parameters('location')]",
            "properties": {
                "maintenanceScope": "Resource",
                "extensionProperties": {
                   "maintenanceSubScope": "SFMC"
                },
                "maintenanceWindow": {
                    "startDateTime": "2023-05-30 22:00",
                    "duration": "05:00",
                    "timeZone": "Pacific Standard Time",
                    "expirationDateTime": null,
                    "recurEvery": "1Day"
                }
            }
        }

After the maintenance configuration is created, it has to be attached to the SFMC cluster, using the assignment resource. More details about assignment:

    "resources": [
        { 
           "type": "Microsoft.Resources/deployments",
            "apiVersion": "2022-09-01",
            "name": "ConfigurationAssignmentsName",
            "dependsOn": [
                "[concat('Microsoft.Maintenance/maintenanceConfigurations/', 'mc1')]",
                "[concat('Microsoft.ServiceFabric/managedclusters/', parameters('clusterName'))]"
            ],
            "properties": {
                "mode": "Incremental",
                "template": {
                    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
                    "resources": [
                        {
                            "apiVersion": "2022-07-01-preview",
                            "type": "Microsoft.Maintenance/configurationAssignments",
                            "name": "mc1Assignment",
                            "location": "[parameters('location')]",
                            "scope": "[concat('Microsoft.ServiceFabric/managedclusters/', parameters('clusterName'))]",
                            "tags": {},
                            "properties": {
                                "maintenanceConfigurationId": "/subscriptions/<subId>/resourcegroups/<rgName>/providers/microsoft.maintenance/maintenanceconfigurations/mc1"
                            }
                        }
                    ]
                }
            },
            "subscriptionId": "<subId>",
            "resourceGroup": "<rgName>"
        }