Configure SQL Server Always On availability groups with synchronous commit using a distributed network name

Microsoft SQL ServerAlways On availability groups let you replicate databases across multiple SQL Server Enterprise instances.

Similar toSQL Server Failover Cluster Instances,Always On availability groups use Windows Server Failover Clustering (WSFC) toimplement high availability. However, the two features differ in the followingways:

Always On availability groupsFailover cluster instances
Scope of fail-overGroup of databasesInstance
StorageNot sharedShared

For a more detailed comparison, seeComparison of failover cluster instances and availability groups.

Always On availability groups supportmultiple availability modes.This tutorial shows how you can deploy Always On availability groups insynchronous commit mode to implement high availability for one or more databases.

In the setup, you will create three VM instances. Two VM instances,node-1 andnode-2 serve as cluster nodes and run SQL Server.A third VM instance,witness, is used to achieve aquorumin a failover scenario.The three VM instances are distributed over three zones and share a common subnet.

Using a SQL Server Always On availability group, an example database,bookshelf,is synchronously replicated across the two SQL Server instances.

In an on-premises Windows cluster environment,Address Resolution Protocol (ARP) announcementstriggerIP address failover.Google Cloud, however, disregards ARP announcements. Consequently, you must implement one of the following two options: using an internal load balancer and a distributed network name (DNN).

The article assumes that you have already deployed Active Directory on Google Cloudand that you have basic knowledge of SQL Server, Active Directory, and Compute Engine.For more information about Active Directory on Google Cloud,see sectionBefore you begin.

Using a SQL Server Always On availability group, an example database,bookshelf,is synchronously replicated across the two SQL Server instances. A distributednetwork name (DNN) listener in front of the cluster provides a single endpointfor SQL Server clients.

For more information about DNN, seeConfigure a DNN listener for an availability group.

Architecture

This diagram includes the following:

  • Two VM instances in the same region and different zones for the failovercluster callednode-1 andnode-2. One hosts the primary replica of theSQL Server database while the other node hosts the secondary replica.
  • A third VM calledwitness serves as a file share witness to provide atie-breaking vote and achieve a quorum for failover.
  • A DNN listener in front of the cluster provides a single endpoint for SQLServer clients.

Objectives

Costs

This tutorial uses billable components of Google Cloud,including:

Use thepricing calculator to generate a cost estimate based on your projected usage.

Before you begin

To complete the tasks in this tutorial, ensure the following:

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
  2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains theresourcemanager.projects.create permission.Learn how to grant roles.
    Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

    Go to project selector

  3. Verify that billing is enabled for your Google Cloud project.

  4. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains theresourcemanager.projects.create permission.Learn how to grant roles.
    Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

    Go to project selector

  5. Verify that billing is enabled for your Google Cloud project.

  6. You have an Active Directory domain with at least one domain controller. You can create anActive Directory domain using Managed Microsoft AD. Alternatively, you can deploy acustom Active Directory environment on Compute Engine and set up aprivate DNS forwarding zone that forwards DNS queries to your domain controllers.
  7. You have an Active Directory user that has permission to join computers to the domain and can sign in by using RDP. If you're using Managed Microsoft AD, you can use thesetupadmin user. For more information about Active Directory user account provisioning, seeActive Directory user account provisioning
  8. A Google Cloud project and a Virtual Private Cloud (VPC) with connectivity to your Active Directory domain controllers.
  9. A subnet to use for the Windows Server Failover Cluster VM instances.
When you finish this tutorial, you can avoid continued billing by deleting theresources you created. For more information, seeCleaning up.

Prepare your project and network

To deploy your SQL Server Always On availability groups, you must prepare yourGoogle Cloud project and VPC for the deployment. The following sections discusshow you can do this in detail.

Configure your project and region

To prepare your Google Cloud project for the deployment of SQL Server Always Onavailability groups, do the following:

  1. In the Google Cloud console, openCloud Shell by clicking theActivate Cloud ShellActivate Cloud Shell.button.

    Go to the Google Cloud console

  2. Initialize the following variables.

    VPC_NAME=VPC_NAMESUBNET_NAME=SUBNET_NAME

    Replace the following:

    • VPC_NAME: name of your VPC
    • SUBNET_NAME: name of your subnet
  3. Set your defaultproject ID.

    gcloud config set projectPROJECT_ID

    ReplacePROJECT_ID with the ID of your Google Cloud project.

  4. Set your default region.

    gcloud config set compute/regionREGION

    ReplaceREGION with the ID of theregion you want to deploy in.

Create firewall rules

To allow clients to connect to the SQL Server and the communication between thecluster nodes you need to create several firewall rules. You can usenetwork tagsto simplify the creation of these firewall rules, as follows:

  • The two cluster nodes are annotated with thewsfc-node tag.
  • All servers (including thewitness) are annotated with thewsfc tag.

To create firewall rules that use these network tags, use the following steps:

  1. Return to your existing Cloud Shell session.
  2. Create firewall rules to allow traffic between cluster nodes.

    SUBNET_CIDR=$(gcloud compute networks subnets describe $SUBNET_NAME --format=value\('ipCidrRange'\))gcloud compute firewall-rules create allow-all-between-wsfc-nodes \  --direction=INGRESS \  --action=allow \  --rules=tcp,udp,icmp \  --enable-logging \  --source-tags=wsfc \  --target-tags=wsfc \  --network=$VPC_NAME \  --priority 10000gcloud compute firewall-rules create allow-sql-to-wsfc-nodes \  --direction=INGRESS \  --action=allow \  --rules=tcp:1433 \  --enable-logging \  --source-ranges=$SUBNET_CIDR \  --target-tags=wsfc-node \  --network=$VPC_NAME \  --priority 10000
Note: Depending on how you've deployed the Active Directory, you might need to createadditional firewall rules to allow servers to join the domain. For moreinformation, seeAccessing Managed Microsoft AD from within your VPC.

Create VM instances

Create and deploy two VM instances for the failover cluster. At any point in time,one of these VMs hosts the primary replica of the SQL Server databasewhile the other node hosts the secondary replica. The two VM instances must:

You use aSQL Server premium imagewhich has SQL Server 2022 preinstalled.

Note: If you plan to bring your own licenses for SQL Server by using theLicense Mobility program,select Windows Server base images for these nodes and install SQL Serverusing your own product keys.

To provide a tie-breaking vote and achieve a quorum for the failover scenario,deploy a third VM that serves as afile share witness using the following steps:

  1. Return to your existing Cloud Shell session.
  2. Create aspecialized scriptfor the WSFC nodes. This script installs the necessary Windows features andcreates firewall rules for WSFC and SQL Server.

    cat << "EOF" > specialize-node.ps1$ErrorActionPreference = "stop"# Install required Windows featuresInstall-WindowsFeature Failover-Clustering -IncludeManagementToolsInstall-WindowsFeature RSAT-AD-PowerShell# Open firewall for WSFCnetsh advfirewall firewall add rule name="Allow WSFC health check" dir=in action=allow protocol=TCP localport=59998# Open firewall for SQL Servernetsh advfirewall firewall add rule name="Allow SQL Server" dir=in action=allow protocol=TCP localport=1433# Open firewall for SQL Server replicationnetsh advfirewall firewall add rule name="Allow SQL Server replication" dir=in action=allow protocol=TCP localport=5022# Format data diskGet-Disk | Where partitionstyle -eq 'RAW' | Initialize-Disk -PartitionStyle MBR -PassThru | New-Partition -AssignDriveLetter -UseMaximumSize | Format-Volume -FileSystem NTFS -NewFileSystemLabel 'Data' -Confirm:$false# Create data and log folders for SQL Servermd d:\Datamd d:\LogsEOF
  3. Create the VM instances. On the two VMs that serve as cluster nodes,attach an additional data disk and enable the Windows Server Failover Clusteringby setting the metadata keyenable-wsfc totrue:

    REGION=$(gcloud config get-value compute/region)ZONE1=ZONE1ZONE2=ZONE2ZONE3=ZONE3PD_SIZE=200MACHINE_TYPE=n2-standard-8gcloud compute instances create node-1 \  --zone $ZONE1 \  --machine-type $MACHINE_TYPE \  --subnet $SUBNET_NAME \  --image-family sql-ent-2022-win-2022 \  --image-project windows-sql-cloud \  --tags wsfc,wsfc-node \  --boot-disk-size 50 \  --boot-disk-type pd-ssd \  --boot-disk-device-name "node-1" \  --create-disk=name=node-1-datadisk,size=$PD_SIZE,type=pd-ssd,auto-delete=no \  --metadata enable-wsfc=true \  --metadata-from-file=sysprep-specialize-script-ps1=specialize-node.ps1gcloud compute instances create node-2 \  --zone $ZONE2 \  --machine-type $MACHINE_TYPE \  --subnet $SUBNET_NAME \  --image-family sql-ent-2022-win-2022 \  --image-project windows-sql-cloud \  --tags wsfc,wsfc-node \  --boot-disk-size 50 \  --boot-disk-type pd-ssd \  --boot-disk-device-name "node-2" \  --create-disk=name=node-2-datadisk,size=$PD_SIZE,type=pd-ssd,auto-delete=no \  --metadata enable-wsfc=true \  --metadata-from-file=sysprep-specialize-script-ps1=specialize-node.ps1gcloud compute instances create "witness" \  --zone $ZONE3 \  --machine-type e2-medium \  --subnet $SUBNET_NAME \  --image-family=windows-2022 \  --image-project=windows-cloud \  --tags wsfc \  --boot-disk-size 50 \  --boot-disk-type pd-ssd \  --metadata sysprep-specialize-script-ps1="add-windowsfeature FS-FileServer"

    ReplaceZONE1,ZONE2,ZONE3 based onthe zones you are using.

    Note: Depending on yourperformance requirements,consider using a machine type larger thann2-standard-8 for the WSFCnodes. Considerdisabling Simultaneous multithreading (SMT)for potential savings on licensing costs.Note: For the purpose of this tutorial, and to fit within the defaultregional SSD Persistent Disk quota, the size of the disks attached to eachVM is smaller than it would be in a production environment. For betterperformance and to accommodate a larger database, increase thesize of each disk.
  4. To join the three VM instances to Active Directory, do the following for each ofthe three VM instances:

    1. Monitor the initialization process of the VM by viewing its serial port output.

      gcloud compute instances tail-serial-port-outputNAME

      ReplaceNAME with the name of the VM instance.

      Wait for a few minutes until you see the outputInstance setup finished,then press Ctrl+C. At this point, the VM instance is ready to be used.

    2. Create a username and passwordfor the VM instance.

    3. Connect to the VM by using Remote Desktopand sign in using the username and password created in the previous step.

    4. Right-click theStart button (or pressWin+X) and clickWindows PowerShell (Admin).

      Note: In this guide, we used Powershell 5.1.
    5. Confirm the elevation prompt by clickingYes.

    6. Join the computer to your Active Directory domain and restart.

      Add-Computer -DomainDOMAIN -Restart

      ReplaceDOMAIN with the DNS name of your Active Directory domain.

    7. Enter the credentials of an account that has permissions to join a VM tothe domain

      Wait for the VM to restart. You have now joined the VM instance to theActive Directory.

Deploying the failover cluster

You can now use the VM instances to deploy a Windows Server Failover Cluster and SQLServer. The following sections discuss how you can do this in detail.

Preparing SQL Server

Create a new user account in Active Directory for SQL Server using the followingsteps.

  1. Connect tonode-1by using Remote Desktop.Sign in with your domain user account.
  2. Right-click theStart button (or pressWin+X) and clickWindows PowerShell (Admin).
  3. Confirm the elevation prompt by clickingYes.
  4. Create a domain user account for SQL server and the SQL agent and assigna password:

    $Credential = Get-Credential -UserName sql_server -Message 'Enter password'New-ADUser `  -Name "sql_server" `  -Description "SQL Admin account." `  -AccountPassword $Credential.Password `  -Enabled $true -PasswordNeverExpires $true
    Note: If you use Managed AD, append-Path "OU=Cloud,DC=example,DC=org"to the command to create the user in theCloud organizational units (OU).Ensure that the value of the path is the output of the following command:Get-ADOrganizationalUnit -Filter "Name -eq 'Cloud'" | Select-Object -ExpandProperty DistinguishedName

To configure SQL Server, perform the following steps on bothnode-1 andnode-2, use the following steps:

  1. OpenSQL Server Configuration Manager.
  2. In the navigation pane, selectSQL Server Services.
  3. In the list of services, right-clickSQL Server (MSSQLSERVER) and selectProperties.
  4. UnderLog on as, change the account as follows:

  5. ClickOK.

  6. When prompted to restart SQL Server, selectYes.

SQL Server now runs under a domain user account.

Warning: Make sure you've completed the previous configuration steps on bothVM instances, otherwise setting up the Always On availability group will fail.

Create file shares

Create two file shares on the VM instancewitness so that it canstore SQL Server backups and act as a file share witness:

  1. Connect towitness byusing Remote Desktop.Sign in with your domain user account.
  2. Right-click theStart button (or pressWin+X) and clickWindows PowerShell (Admin).
  3. Confirm the elevation prompt by clickingYes.
  4. Create a witness file share and grant yourself and the two cluster nodesaccess to the file share.

    New-Item "C:\QWitness" –type directoryicacls C:\QWitness\ /grant 'node-1$:(OI)(CI)(M)'icacls C:\QWitness\ /grant 'node-2$:(OI)(CI)(M)'New-SmbShare `  -Name QWitness `  -Path "C:\QWitness" `  -Description "SQL File Share Witness" `  -FullAccess $env:username,node-1$,node-2$
  5. Create another file share to store backups and grant SQL Server full access:

    New-Item "C:\Backup" –type directoryNew-SmbShare `  -Name Backup `  -Path "C:\Backup" `  -Description "SQL Backup" `  -FullAccess  $env:USERDOMAIN\sql_server

Create the failover cluster

To create the failover cluster, use the following steps:

  1. Return to the Remote Desktop session onnode-1.
  2. Right-click theStart button (or pressWin+X) and clickWindows PowerShell (Admin).
  3. Confirm the elevation prompt by clickingYes.
  4. Create a new cluster.

    New-Cluster `  -Name sql-cluster `  -Node node-1,node-2 `  -NoStorage `  -ManagementPointNetworkType Distributed
    Note: Whencomputer objects are created outside the containerComputers (in anOU), the permissionCreate Computer objects must be delegatedto the cluster's computer account in the OU.
  5. Return to the PowerShell session onwitness and grant the virtualcomputer object of the cluster permission to access the file share.

    icacls C:\QWitness\ /grant 'sql-cluster$:(OI)(CI)(M)'Grant-SmbShareAccess `  -Name QWitness `  -AccountName 'sql-cluster$' `  -AccessRight Full `  -Force
  6. Return to the PowerShell session onnode-1 and configure the clusterto use the file share onwitness as a cluster quorum.

    Set-ClusterQuorum -FileShareWitness \\witness\QWitness
  7. Verify that the cluster was created successfully.

    Test-Cluster

    You might see some warnings that can be safely ignored:

    WARNING: System Configuration - Validate All Drivers Signed: The test reported some warnings..WARNING: Network - Validate Network Communication: The test reported some warnings..WARNING:Test Result:HadUnselectedTests, ClusterConditionallyApprovedTesting has completed for the tests you selected. You should review the warnings in the Report.  A cluster solution issupported by Microsoft only if you run all cluster validation tests, and all tests succeed (with or without warnings).

    You can also launch the Failover Cluster Manager MMC snap-in to review thecluster's health by runningcluadmin.msc.

  8. If you're using Managed AD, add the computer account used by the Windows clusterto theCloud Service Domain Join Accounts group so that it can joincomputers to the domain.

    Add-ADGroupMember `  -Identity "Cloud Service Domain Join Accounts" `  -Members sql-cluster$
  9. Enable Always On availability groups on both nodes.

    Enable-SqlAlwaysOn -ServerInstance node-1 -ForceEnable-SqlAlwaysOn -ServerInstance node-2 -Force
Note: To get a single cluster endpoint for administrative purposes and managingcluster resources, you can use the DNS Name of the cluster returned by runningtheResolve-DnsName -Name sql-cluster Powershell command.

Creating an availability group

You now create a sample databasebookshelf, include it in a new availabilitygroup namedbookshelf-ag and configure high availability.

Creating a database

Create a new database. For the purpose of this tutorial, the database doesn'tneed to contain any data.

  1. Return to the Remote Desktop session onnode-1.
  2. Open theSQL Server Management Studio.
  3. In theConnect to server dialog, verify the server name is set tonode-1 and selectConnect.
  4. In the menu, selectFile > New > Query with current connection.
  5. Paste the following SQL script into the editor:

    -- Create a sample databaseCREATE DATABASE bookshelf ON PRIMARY (  NAME = 'bookshelf',  FILENAME='d:\Data\bookshelf.mdf',  SIZE = 256MB,  MAXSIZE = UNLIMITED,  FILEGROWTH = 256MB)LOG ON (  NAME = 'bookshelf_log',  FILENAME='d:\Logs\bookshelf.ldf',  SIZE = 256MB,  MAXSIZE = UNLIMITED,  FILEGROWTH = 256MB)GOUSE [bookshelf]SET ANSI_NULLS ONSET QUOTED_IDENTIFIER ONGO-- Create sample tableCREATE TABLE [dbo].[Books] (  [Id] [bigint] IDENTITY(1,1) NOT NULL,  [Title] [nvarchar](max) NOT NULL,  [Author] [nvarchar](max) NULL,  [PublishedDate] [datetime] NULL,  [ImageUrl] [nvarchar](max) NULL,  [Description] [nvarchar](max) NULL,  [CreatedById] [nvarchar](max) NULL,  CONSTRAINT [PK_dbo.Books] PRIMARY KEY CLUSTERED ([Id] ASC) WITH (    PAD_INDEX = OFF,    STATISTICS_NORECOMPUTE = OFF,    IGNORE_DUP_KEY = OFF,    ALLOW_ROW_LOCKS = ON,    ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]GO-- Create a backupEXEC dbo.sp_changedbowner @loginame = 'sa', @map = false;  ALTER DATABASE [bookshelf] SET RECOVERY FULL;  GO  BACKUP DATABASE bookshelf to disk = '\\witness\Backup\bookshelf.bak' WITH INITGO

    The script creates a new database with a single table and performs aninitial backup towitness.

  6. SelectExecute to run the SQL script.

Configure high availability

You can now configure high availability for the availability group using eitherT-SQL or Server Management Studio.

Using T-SQL

To configure high availability for the availability group using T-SQL, use thefollowing steps:

  1. Connect tonode-1 and then execute the following script to create thebookshelf-ag availability group.

    CREATE LOGIN [NET_DOMAIN\sql_server] FROM WINDOWS;GOUSE [bookshelf];CREATE USER [NET_DOMAIN\sql_server] FOR LOGIN [NET_DOMAIN\sql_server];GOUSE [master];CREATE ENDPOINT bookshelf_endpoint  STATE=STARTED  AS TCP (LISTENER_PORT=5022)  FOR DATABASE_MIRRORING (ROLE=ALL);GOGRANT CONNECT ON ENDPOINT::[bookshelf_endpoint] TO [NET_DOMAIN\sql_server]GO
    Note: In theNET_DOMAIN\sql_server login and user,NET_DOMAIN is the NetBIOS name of your Active Directory domain.
  2. Connect tonode-2 and execute the following script.

    CREATE LOGIN [NET_DOMAIN\sql_server] FROM WINDOWS;GOCREATE ENDPOINT bookshelf_endpoint  STATE=STARTED  AS TCP (LISTENER_PORT=5022)  FOR DATABASE_MIRRORING (ROLE=ALL);GOGRANT CONNECT ON ENDPOINT::[bookshelf_endpoint] TO [NET_DOMAIN\sql_server]GO
    Note: In theNET_DOMAIN\sql_server login and user,NET_DOMAIN is the NetBIOS name of your Active Directory domain.
  3. Onnode-1 and then execute the following script to create thebookshelf-agavailability group.

    USE master;GOCREATE AVAILABILITY GROUP [bookshelf-ag]WITH (AUTOMATED_BACKUP_PREFERENCE = SECONDARY,CLUSTER_TYPE = WSFC,DB_FAILOVER = ON)FOR DATABASE [bookshelf]REPLICA ON  N'node-1' WITH (      ENDPOINT_URL = 'TCP://node-1:5022',      AVAILABILITY_MODE = SYNCHRONOUS_COMMIT,      FAILOVER_MODE = AUTOMATIC,      BACKUP_PRIORITY = 50,      SEEDING_MODE = AUTOMATIC,      SECONDARY_ROLE(ALLOW_CONNECTIONS = NO)  ),  N'node-2' WITH (      ENDPOINT_URL = 'TCP://node-2:5022',      AVAILABILITY_MODE = SYNCHRONOUS_COMMIT,      FAILOVER_MODE = AUTOMATIC,      BACKUP_PRIORITY = 50,      SEEDING_MODE = AUTOMATIC,      SECONDARY_ROLE(ALLOW_CONNECTIONS = NO)  );GO
  4. Connect tonode-2 and then execute the following script to join thesecondary replica to the availability group and enable automatic seeding.

    USE master;GOALTER AVAILABILITY GROUP [bookshelf-ag] JOIN;ALTER AVAILABILITY GROUP [bookshelf-ag] GRANT CREATE ANY DATABASE;
  5. Check the status of the availability group.

    SELECT * FROM sys.dm_hadr_availability_group_states;GO

    You should seesynchronization_health_desc asHEALTHY.

Using SQL Server Management Studio

To configure high availability for the availability group using SQL ServerManagement Studio, use the following steps:

  1. In theObject Explorer window, right-clickAlways On High Availabilityand then selectNew Availability Group Wizard.
  2. On theSpecify Options page, set the availability group name tobookshelf-ag, then selectNext.
  3. On theSelect Databases page, select thebookshelf database,then selectNext.
  4. On theSpecify Replicas page, select theReplicas tab.

    1. SelectAdd replica.
    2. In theConnect to server dialog, enter the server namenode-2 andselectConnect.

      The list of availability replicas now contains SQL Server instances,node-1 andnode-2.

    3. Set theAvailability mode toSynchronous commit for both instances.

    4. SetAutomatic failover toEnabled for both instances.

    5. SelectNext.

  5. On theSelect Data Synchronization page, selectAutomatic Seeding.

  6. On theValidation page, verify that all checks are successful. You canignore the availability group listener check.

  7. On theSummary page, selectFinish.

  8. On theResults page, selectClose.

Configure a DNN listener for the availability group

A DNN listener serves as a single endpoint for SQL Server clients. To configurea DNN listener, use the following steps:

  1. Return to the PowerShell session onnode-1.
  2. Execute the following script to create a DNN listener.

      $Ag='bookshelf-ag'  $Port='DNN_PORT'  $Dns='DNN_NAME'  # create the DNN resource with the port as the resource name  Add-ClusterResource -Name $Port -ResourceType "Distributed Network Name" -Group $Ag  # set the DNS name of the DNN resource  Get-ClusterResource -Name $Port | Set-ClusterParameter -Name DnsName -Value $Dns  # start the DNN resource  Start-ClusterResource -Name $Port  # add the Dependency from availability group resource to the DNN resource  Set-ClusterResourceDependency -Resource $Ag -Dependency "[$Port]"  # restart the availability group resource  Stop-ClusterResource -Name $Ag  Start-ClusterResource -Name $Ag

    ReplaceDNN_PORT with the DNN listener port. The DNN listener port must be configured with a unique port. For more information, seePort considerations.

    ReplaceDNN_NAME with the DNN listener name.

  3. Create firewall rules for DNN listener port on bothnode-1 andnode-2.

      netsh advfirewall firewall add rule name="Allow DNN listener" dir=in action=allow protocol=TCP localport=DNN_PORT

Test the failover

You are now ready to test if the failover works as expected:

  1. Return to the PowerShell session onwitness.
  2. Run the following script.

    while ($True){  $Conn = New-Object System.Data.SqlClient.SqlConnection  $Conn.ConnectionString = "Server=DNN_NAME,DNN_PORT;Integrated Security=true;Initial Catalog=master"  $Conn.Open()  $Cmd = New-Object System.Data.SqlClient.SqlCommand  $Cmd.Connection = $Conn  $Cmd.CommandText = "SELECT SERVERPROPERTY('ServerName')"  $Adapter = New-Object System.Data.SqlClient.SqlDataAdapter $Cmd  $Data = New-Object System.Data.DataSet  $Adapter.Fill($Data) | Out-Null  $Data.Tables[0] + (Get-Date -Format "MM/dd/yyyy HH:mm:ss")  Start-Sleep -Seconds 2}

    ReplaceDNN_NAME with the DNN listener name andDNN_PORT with the DNN listener port.

    Every 2 seconds, the script connects to SQL Server by using the availabilitygroup listener, and queries the server name.

    Leave the script running.

  3. Return to the Remote Desktop session onnode-1 to trigger a failover.

    1. InSQL Server Management Studio, navigate toAlways OnHigh Availability > Availability Groups > bookshelf-ag (Primary) andright-click the node.
    2. SelectFailover.
    3. On theSelect new primary replica page, verify thatnode-2 is selectedas new primary replica and that theFailover readiness columnindicatesNo data loss. Then selectNext.
    4. On theConnect to replica page, selectConnect.
    5. In theConnect to server dialog, verify that the server name isnode-2 andclickConnect.
    6. SelectNext and thenFinish.
    7. On theResults page, verify that the failover was successful.
  4. Return to the PowerShell session onwitness.

  5. Observe the output of the running script and notice that the server namechanges fromnode-1 tonode-2 as a result of the failover.

  6. Stop the script by pressingCtrl+C.

Clean up

After you finish the tutorial, you can clean up the resources that you created so that they stop using quota and incurring charges. The following sections describe how to delete or turn off these resources.

Deleting the project

The easiest way to eliminate billing is to delete the project that you created for the tutorial.

To delete the project:

    Caution: Deleting a project has the following effects:
    • Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
    • Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as anappspot.com URL, delete selected resources inside the project instead of deleting the whole project.

    If you plan to explore multiple architectures, tutorials, or quickstarts, reusing projects can help you avoid exceeding project quota limits.

  1. In the Google Cloud console, go to theManage resources page.

    Go to Manage resources

  2. In the project list, select the project that you want to delete, and then clickDelete.
  3. In the dialog, type the project ID, and then clickShut down to delete the project.

What's next

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Last updated 2025-12-15 UTC.