App Service recovery on Azure Stack Hub

This topic provides instructions on what actions to take for App Service disaster recovery.

The following actions must be taken to recover App Service on Azure Stack Hub from backup:

1. Restore the App Service databases.
2. Restore the file server share content.
3. Restore App Service roles and services.

If Azure Stack Hub storage was used for Function Apps storage, then you must also take steps to restore Function Apps.

Restore the App Service databases

The App Service SQL Server databases should be restored on a production ready SQL Server instance.

After preparing the SQL Server instance to host the App Service databases, use these steps to restore databases from backup:

1. Sign in to the SQL Server that will host the recovered App Service databases with admin permissions.
2. Use the following commands to restore the App Service databases from a command prompt running with admin permissions:

   sqlcmd -U <SQL admin login> -P <SQL admin password> -Q "RESTORE DATABASE appservice_hosting FROM DISK='<full path to backup>' WITH REPLACE"
   sqlcmd -U <SQL admin login> -P <SQL admin password> -Q "RESTORE DATABASE appservice_metering FROM DISK='<full path to backup>' WITH REPLACE"
   

3. Verify that both App Service databases have been successfully restored and exit SQL Server Management Studio.

Note

To recover from a failover cluster instance failure, see Recover from Failover Cluster Instance Failure.

Restore the App Service file share content

After preparing the file server to host the App Service file share, you need to restore the tenant file share content from backup. You can use whatever method you have available to copy the files into the newly created App Service file share location. Running this example on the file server will use PowerShell and robocopy to connect to a remote share and copy the files to the share:

$source = "<remote backup storage share location>"
$destination = "<local file share location>"
net use $source /user:<account to use to connect to the remote share in the format of domain\username> *
robocopy /E $source $destination
net use $source /delete

In addition to copying the file share contents, you must also reset permissions on the file share itself. To reset permissions, open an admin command prompt on the file server computer and run the ReACL.cmd file. The ReACL.cmd file is located in the App Service installation files in the BCDR directory.

Restore App Service roles and services

After the App Service databases and file share content are restored, you next need to use PowerShell to restore the App Service roles and services. These steps will restore App Service secrets and service configurations.

1. Log into the App Service controller CN0-VM VM as roleadmin using the password you provided during App Service installation.

   Tip

   You need to modify the VM's network security group to allow RDP connections.

2. Copy the SystemSecrets.JSON file locally to the controller VM. You need to provide the path to this file as the $pathToExportedSecretFile parameter in the next step.

3. Use the following commands in an elevated PowerShell console window to restore App Service roles and services:

   # Stop App Service services on the primary controller VM
   net stop WebFarmService
   net stop ResourceMetering
   net stop HostingVssService # This service was deprecated in the App Service 1.5 release and is not required after the App Service 1.4 release.
   
   # Restore App Service secrets. Provide the path to the App Service secrets file copied from backup. For example, C:\temp\SystemSecrets.json.
   # Press ENTER when prompted to reconfigure App Service from backup 
   
   # If necessary, use -OverrideDatabaseServer <restored server> with Restore-AppServiceStamp when the restored database server has a different address than backed-up deployment.
   # If necessary, use -OverrideContentShare <restored file share path> with Restore-AppServiceStamp when the restored file share has a different path from backed-up deployment.
   Restore-AppServiceStamp -FilePath $pathToExportedSecretFile 
   
   # Restore App Service roles
   Restore-AppServiceRoles
   
   # Restart App Service services
   net start WebFarmService
   net start ResourceMetering
   net start HostingVssService  # This service was deprecated in the App Service 1.5 release and is not required after the App Service 1.4 release.
   
   # After App Service has successfully restarted, and at least one management server is in ready state, synchronize App Service objects to complete the restore
   # Enter Y when prompted to get all sites and again for all ServerFarm entities.
   Get-AppServiceSite | Sync-AppServiceObject
   Get-AppServiceServerFarm | Sync-AppServiceObject
   

Tip

It's highly recommended to close this PowerShell session when the command completes.

Restore Function Apps

App Service for Azure Stack Hub doesn't support restoring tenant user apps or data other than file share content. All other data must be backed up and recovered outside of App Service backup and restore operations. If Azure Stack Hub storage was used for Function Apps storage, the following steps should be taken to recover lost data:

1. Create a new storage account to be used by the Function App. This storage can be Azure Stack Hub storage, Azure storage, or any compatible storage.
2. Retrieve the connection string for the storage.
3. Open the function portal and browse to the function app.
4. Browse to the Platform features tab and click Application Settings.
5. Change AzureWebJobsDashboard and AzureWebJobsStorage to the new connection string and click Save.
6. Switch to Overview.
7. Restart the app. It might take several tries to clear all errors.

Next steps

App Service on Azure Stack Hub overview