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Configure link with scripts - Azure SQL Managed Instance

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Applies to: Azure SQL Managed Instance

This article teaches you how to configure a link between SQL Server and Azure SQL Managed Instance with Transact-SQL and PowerShell or Azure CLI scripts. With the link, databases from your initial primary are replicated to your secondary replica in near-real time.

After the link is created, you can then fail over to your secondary replica for the purpose of migration, or disaster recovery.

Note

Overview

Use the link feature to replicate databases from your initial primary to your secondary replica. For SQL Server 2022, the initial primary can be either SQL Server or Azure SQL Managed Instance. For SQL Server 2019 and earlier versions, the initial primary must be SQL Server. After the link is configured, the database from the initial primary is replicated to the secondary replica.

You can choose to leave the link in place for continuous data replication in a hybrid environment between the primary and secondary replica, or you can fail over the database to the secondary replica, to migrate to Azure, or for disaster recovery. For SQL Server 2019 and earlier versions, failing over to Azure SQL Managed Instance breaks the link and fail back is unsupported. With SQL Server 2022, you have the option to maintain the link and fail back and forth between the two replicas.

If you plan to use your secondary managed instance for only disaster recovery, you can save on licensing costs by activating the hybrid failover benefit.

Use the instructions in this article to manually set up the link between SQL Server and Azure SQL Managed Instance. After the link is created, your source database gets a read-only copy on your target secondary replica.

Tip

To simplify using T-SQL scripts with the correct parameters for your environment, we strongly recommend using the Managed Instance link wizard in SQL Server Management Studio (SSMS) to generate a script to create the link. On the Summary page of the New Managed Instance link window, select Script instead of Finish.

Prerequisites

To replicate your databases, you need the following prerequisites:

Consider the following:

  • The link feature supports one database per link. To replicate multiple databases on an instance, create a link for each individual database. For example, to replicate 10 databases to SQL Managed Instance, create 10 individual links.
  • Collation between SQL Server and SQL Managed Instance should be the same. A mismatch in collation could cause a mismatch in server name casing and prevent a successful connection from SQL Server to SQL Managed Instance.
  • Error 1475 on your initial SQL Server primary indicates that you need to start a new backup chain by creating a full backup without the COPY ONLY option.
  • To establish a link, or fail over, from SQL Managed Instance to SQL Server 2022, your managed instance must be configured with the SQL Server 2022 update policy. Data replication and failover from SQL Managed Instance to SQL Server 2022 is not supported by instances configured with the Always-up-to-date update policy.
  • While you can establish a link from SQL Server 2022 to a SQL managed instance configured with the Always-up-to-date update policy, after failover to SQL Managed Instance, you will no longer be able to replicate data or fail back to SQL Server 2022.

Permissions

For SQL Server, you should have sysadmin permissions.

For Azure SQL Managed Instance, you should be a member of the SQL Managed Instance Contributor, or have the following custom role permissions:

Microsoft.Sql/ resource Necessary permissions
Microsoft.Sql/managedInstances /read, /write
Microsoft.Sql/managedInstances/hybridCertificate /action
Microsoft.Sql/managedInstances/databases /read, /delete, /write, /completeRestore/action, /readBackups/action, /restoreDetails/read
Microsoft.Sql/managedInstances/distributedAvailabilityGroups /read, /write, /delete, /setRole/action
Microsoft.Sql/managedInstances/endpointCertificates /read
Microsoft.Sql/managedInstances/hybridLink /read, /write, /delete
Microsoft.Sql/managedInstances/serverTrustCertificates /write, /delete, /read

Terminology and naming conventions

As you run scripts from this user guide, it's important not to mistake SQL Server and SQL Managed Instance names for their fully qualified domain names (FQDNs). The following table explains what the various names exactly represent and how to obtain their values:

Terminology Description How to find out
Initial primary 1 The SQL Server or SQL Managed Instance where you initially create the link to replicate your database to the secondary replica.
Primary replica The SQL Server or SQL Managed Instance that currently hosts the primary database.
Secondary replica The SQL Server or SQL Managed Instance that is receiving near-real time replicated data from the current primary replica.
SQL Server name Short, single-word SQL Server name. For example: sqlserver1. Run SELECT @@SERVERNAME from T-SQL.
SQL Server FQDN Fully qualified domain name (FQDN) of your SQL Server. For example: sqlserver1.domain.com. See your network (DNS) configuration on-premises, or the server name if you're using an Azure virtual machine (VM).
SQL Managed Instance name Short, single-word SQL Managed Instance name. For example: managedinstance1. See the name of your managed instance in the Azure portal.
SQL Managed Instance FQDN Fully qualified domain name (FQDN) of your SQL Managed Instance. For example: managedinstance1.6d710bcf372b.database.windows.net. See the host name on the SQL Managed Instance overview page in the Azure portal.
Resolvable domain name DNS name that can be resolved to an IP address. For example, running nslookup sqlserver1.domain.com should return an IP address such as 10.0.0.1. Run nslookup command from the command prompt.
SQL Server IP IP address of your SQL Server. In case of multiple IPs on SQL Server, choose IP address that is accessible from Azure. Run ipconfig command from the command prompt of host OS running the SQL Server.

1 Configuring Azure SQL Managed Instance as your initial primary is supported starting with SQL Server 2022 CU10.

Set up database recovery and backup

If SQL Server is your initial primary, then databases that will be replicated via the link must be in the full recovery model and have at least one backup. Since Azure SQL Managed Instance takes backups automatically, skip this step if SQL Managed Instance is your initial primary.

Run the following code on SQL Server for all databases you wish to replicate. Replace <DatabaseName> with your actual database name.

-- Run on SQL Server
-- Set full recovery model for all databases you want to replicate.
ALTER DATABASE [<DatabaseName>] SET RECOVERY FULL
GO

-- Execute backup for all databases you want to replicate.
BACKUP DATABASE [<DatabaseName>] TO DISK = N'<DiskPath>'
GO

For more information, see Create a Full Database Backup.

Note

The link supports replication of user databases only. Replication of system databases is not supported. To replicate instance-level objects (stored in master or msdb databases), we recommend that you script them out and run T-SQL scripts on the destination instance.

Establish trust between instances

First, you must establish trust between the two instances, and secure the endpoints used to communicate and encrypt data across the network. Distributed availability groups use the existing availability group database mirroring endpoint, rather than having their own dedicated endpoint. As such, security and trust need to be configured between the two instances through the availability group database mirroring endpoint.

Note

The link is based on the Always On availability group technology. The database mirroring endpoint is a special-purpose endpoint that is used exclusively by availability groups to receive connections from other instances. The term database mirroring endpoint should not be mistaken with the legacy SQL Server database mirroring feature.

Certificate-based trust is the only supported way to secure database mirroring endpoints for SQL Server and SQL Managed Instance. If you have existing availability groups that use Windows authentication, you need to add certificate-based trust to the existing mirroring endpoint as a secondary authentication option. You can do this by using the ALTER ENDPOINT statement, as shown later in this article.

Important

Certificates are generated with an expiration date and time. They must be renewed and rotated before they expire.

The following lists an overview of the process to secure database mirroring endpoints for both SQL Server and SQL Managed Instance:

  1. Generate a certificate on SQL Server and obtain its public key.
  2. Obtain a public key of the SQL Managed Instance certificate.
  3. Exchange the public keys between SQL Server and SQL Managed Instance.
  4. Import Azure-trusted root certificate authority keys to SQL Server

The following sections describe these steps in detail.

Create a certificate on SQL Server and import its public key to SQL Managed Instance

First, create the database master key in the master database, if it's not already present. Insert your password in place of <strong_password> in the following script, and keep it in a confidential and secure place. Run this T-SQL script on SQL Server:

-- Run on SQL Server
-- Create a master key encryption password
-- Keep the password confidential and in a secure place
USE MASTER
IF NOT EXISTS (SELECT * FROM sys.symmetric_keys WHERE symmetric_key_id = 101)
BEGIN
    PRINT 'Creating master key.' + CHAR(13) + 'Keep the password confidential and in a secure place.'
    CREATE MASTER KEY ENCRYPTION BY PASSWORD = '<strong_password>'
END
ELSE
    PRINT 'Master key already exists.'
GO

Then, generate an authentication certificate on SQL Server. In the following script replace:

  • @cert_expiry_date with the desired certificate expiration date (future date).

Record this date and set a reminder to rotate (update) the SQL server certificate before its expiration date to ensure continuous operation of the link.

Important

It is strongly recommended to use the auto-generated certificate name from this script. While customizing your own certificate name on SQL Server is allowed, the name should not contain any \ characters.

-- Create the SQL Server certificate for the instance link
USE MASTER

-- Customize SQL Server certificate expiration date by adjusting the date below
DECLARE @cert_expiry_date AS varchar(max)='03/30/2025'

-- Build the query to generate the certificate
DECLARE @sqlserver_certificate_name NVARCHAR(MAX) = N'Cert_' + @@servername  + N'_endpoint'
DECLARE @sqlserver_certificate_subject NVARCHAR(MAX) = N'Certificate for ' + @sqlserver_certificate_name
DECLARE @create_sqlserver_certificate_command NVARCHAR(MAX) = N'CREATE CERTIFICATE [' + @sqlserver_certificate_name + '] ' + char (13) +
'    WITH SUBJECT = ''' + @sqlserver_certificate_subject + ''',' + char (13) +
'    EXPIRY_DATE = '''+ @cert_expiry_date + ''''+ char (13)
IF NOT EXISTS (SELECT name from sys.certificates WHERE name = @sqlserver_certificate_name)
BEGIN
    PRINT (@create_sqlserver_certificate_command)
    -- Execute the query to create SQL Server certificate for the instance link
    EXEC sp_executesql @stmt = @create_sqlserver_certificate_command
END
ELSE
    PRINT 'Certificate ' + @sqlserver_certificate_name + ' already exists.'
GO

Then, use the following T-SQL query on SQL Server to verify the certificate has been created:

-- Run on SQL Server
USE MASTER
GO
SELECT * FROM sys.certificates WHERE pvt_key_encryption_type = 'MK'

In the query results, you'll see that the certificate has been encrypted with the master key.

Now, you can get the public key of the generated certificate on SQL Server:

-- Run on SQL Server
-- Show the name and the public key of generated SQL Server certificate
USE MASTER
GO
DECLARE @sqlserver_certificate_name NVARCHAR(MAX) = N'Cert_' + @@servername  + N'_endpoint'
DECLARE @PUBLICKEYENC VARBINARY(MAX) = CERTENCODED(CERT_ID(@sqlserver_certificate_name));
SELECT @sqlserver_certificate_name as 'SQLServerCertName'
SELECT @PUBLICKEYENC AS SQLServerPublicKey;

Save values of SQLServerCertName and SQLServerPublicKey from the output, because you'll need it for the next step when you import the certificate.

First, ensure that you're logged in to Azure and that you've selected the subscription where your managed instance is hosted. Selecting the proper subscription is especially important if you have more than one Azure subscription on your account.

Replace <SubscriptionID> with your Azure subscription ID.

# Run in Azure Cloud Shell (select PowerShell console)

# Enter your Azure subscription ID
$SubscriptionID = "<SubscriptionID>"

# Login to Azure and select subscription ID
if ((Get-AzContext ) -eq $null)
{
    echo "Logging to Azure subscription"
    Login-AzAccount
}
Select-AzSubscription -SubscriptionName $SubscriptionID

Then use either the New-AzSqlInstanceServerTrustCertificate PowerShell or az sql mi partner-cert create Azure CLI command to upload the public key of the authentication certificate from SQL Server to Azure, such as the following PowerShell sample.

Fill out necessary user information, copy it, paste it, and then run the script. Replace:

  • <SQLServerPublicKey> with the public portion of the SQL Server certificate in binary format, which you've recorded in the previous step. It's a long string value that starts with 0x.
  • <SQLServerCertName> with the SQL Server certificate name you've recorded in the previous step.
  • <ManagedInstanceName> with the short name of your managed instance.
# Run in Azure Cloud Shell (select PowerShell console)
# ===============================================================================
# POWERSHELL SCRIPT TO IMPORT SQL SERVER PUBLIC CERTIFICATE TO SQL MANAGED INSTANCE
# ===== Enter user variables here ====

# Enter the name for the server SQLServerCertName certificate – for example, "Cert_sqlserver1_endpoint"
$CertificateName = "<SQLServerCertName>"

# Insert the certificate public key blob that you got from SQL Server – for example, "0x1234567..."
$PublicKeyEncoded = "<SQLServerPublicKey>"

# Enter your managed instance short name – for example, "sqlmi"
$ManagedInstanceName = "<ManagedInstanceName>"

# ==== Do not customize the below cmdlets====

# Find out the resource group name
$ResourceGroup = (Get-AzSqlInstance -InstanceName $ManagedInstanceName).ResourceGroupName

# Upload the public key of the authentication certificate from SQL Server to Azure.
New-AzSqlInstanceServerTrustCertificate -ResourceGroupName $ResourceGroup -InstanceName $ManagedInstanceName -Name $CertificateName -PublicKey $PublicKeyEncoded

The result of this operation is a summary of the uploaded SQL Server certificate to Azure.

If you need to see all SQL Server certificates uploaded to a managed instance, use the Get-AzSqlInstanceServerTrustCertificate PowerShell or az sql mi partner-cert list Azure CLI command in Azure Cloud Shell. To remove SQL Server certificate uploaded to a SQL managed instance, use the Remove-AzSqlInstanceServerTrustCertificate PowerShell or az sql mi partner-cert delete Azure CLI command in Azure Cloud Shell.

Get the certificate public key from SQL Managed Instance and import it to SQL Server

The certificate to secure the link endpoint is automatically generated on Azure SQL Managed Instance. Get the certificate public key from SQL Managed Instance, and import it to SQL Server by using the Get-AzSqlInstanceEndpointCertificate PowerShell or az sql mi endpoint-cert show Azure CLI command, such as the following PowerShell sample.

Caution

When using the Azure CLI, you'll need to manually add 0x to the front of the PublicKey output when you use it in subsequent steps. For example, the PublicKey will look like "0x3082033E30...".

Run the following script. Replace:

  • <SubscriptionID> with your Azure subscription ID.
  • <ManagedInstanceName> with the short name of your managed instance.
# Run in Azure Cloud Shell (select PowerShell console)
# ===============================================================================
# POWERSHELL SCRIPT TO EXPORT MANAGED INSTANCE PUBLIC CERTIFICATE
# ===== Enter user variables here ====

# Enter your managed instance short name – for example, "sqlmi"
$ManagedInstanceName = "<ManagedInstanceName>"

# ==== Do not customize the following cmdlet ====

# Find out the resource group name
$ResourceGroup = (Get-AzSqlInstance -InstanceName $ManagedInstanceName).ResourceGroupName

# Fetch the public key of the authentication certificate from Managed Instance. Outputs a binary key in the property PublicKey.
Get-AzSqlInstanceEndpointCertificate -ResourceGroupName $ResourceGroup -InstanceName $ManagedInstanceName -EndpointType "DATABASE_MIRRORING" | out-string

Copy the entire PublicKey output (starts with 0x) as you'll require it in the next step.

Alternatively, if you encounter issues in copy-pasting the PublicKey, you could also run the T-SQL command EXEC sp_get_endpoint_certificate 4 on the managed instance to obtain its public key for the link endpoint.

Next, import the obtained public key of the managed instance security certificate to SQL Server. Run the following query on SQL Server to create the MI endpoint certificate. Replace:

  • <ManagedInstanceFQDN> with the fully qualified domain name of managed instance.
  • <PublicKey> with the PublicKey value obtained in the previous step (from Azure Cloud Shell, starting with 0x). You don't need to use quotation marks.

Important

The name of the certificate must be the SQL Managed Instance FQDN and should not be modified. The link will not be operational if using a custom name.

-- Run on SQL Server
USE MASTER
CREATE CERTIFICATE [<ManagedInstanceFQDN>]
FROM BINARY = <PublicKey>

Import Azure-trusted root certificate authority keys to SQL Server

Importing public root certificate keys of Microsoft and DigiCert certificate authorities (CA) to SQL Server is required for your SQL Server to trust certificates issued by Azure for database.windows.net domains.

Caution

Ensure the PublicKey starts with an 0x. You might need to add it manually to the beginning of the PublicKey if it's not already there.

First, import the Microsoft PKI root-authority certificate on SQL Server:

-- Run on SQL Server
-- Import Microsoft PKI root-authority certificate (trusted by Azure), if not already present
IF NOT EXISTS (SELECT name FROM sys.certificates WHERE name = N'MicrosoftPKI')
BEGIN
    PRINT 'Creating MicrosoftPKI certificate.'
    CREATE CERTIFICATE [MicrosoftPKI] FROM BINARY = 0x308205A830820390A00302010202101ED397095FD8B4B347701EAABE7F45B3300D06092A864886F70D01010C05003065310B3009060355040613025553311E301C060355040A13154D6963726F736F667420436F72706F726174696F6E313630340603550403132D4D6963726F736F66742052534120526F6F7420436572746966696361746520417574686F726974792032303137301E170D3139313231383232353132325A170D3432303731383233303032335A3065310B3009060355040613025553311E301C060355040A13154D6963726F736F667420436F72706F726174696F6E313630340603550403132D4D6963726F736F66742052534120526F6F7420436572746966696361746520417574686F72697479203230313730820222300D06092A864886F70D01010105000382020F003082020A0282020100CA5BBE94338C299591160A95BD4762C189F39936DF4690C9A5ED786A6F479168F8276750331DA1A6FBE0E543A3840257015D9C4840825310BCBFC73B6890B6822DE5F465D0CC6D19CC95F97BAC4A94AD0EDE4B431D8707921390808364353904FCE5E96CB3B61F50943865505C1746B9B685B51CB517E8D6459DD8B226B0CAC4704AAE60A4DDB3D9ECFC3BD55772BC3FC8C9B2DE4B6BF8236C03C005BD95C7CD733B668064E31AAC2EF94705F206B69B73F578335BC7A1FB272AA1B49A918C91D33A823E7640B4CD52615170283FC5C55AF2C98C49BB145B4DC8FF674D4C1296ADF5FE78A89787D7FD5E2080DCA14B22FBD489ADBACE479747557B8F45C8672884951C6830EFEF49E0357B64E798B094DA4D853B3E55C428AF57F39E13DB46279F1EA25E4483A4A5CAD513B34B3FC4E3C2E68661A45230B97A204F6F0F3853CB330C132B8FD69ABD2AC82DB11C7D4B51CA47D14827725D87EBD545E648659DAF5290BA5BA2186557129F68B9D4156B94C4692298F433E0EDF9518E4150C9344F7690ACFC38C1D8E17BB9E3E394E14669CB0E0A506B13BAAC0F375AB712B590811E56AE572286D9C9D2D1D751E3AB3BC655FD1E0ED3740AD1DAAAEA69B897288F48C407F852433AF4CA55352CB0A66AC09CF9F281E1126AC045D967B3CEFF23A2890A54D414B92AA8D7ECF9ABCD255832798F905B9839C40806C1AC7F0E3D00A50203010001A3543052300E0603551D0F0101FF040403020186300F0603551D130101FF040530030101FF301D0603551D0E0416041409CB597F86B2708F1AC339E3C0D9E9BFBB4DB223301006092B06010401823715010403020100300D06092A864886F70D01010C05000382020100ACAF3E5DC21196898EA3E792D69715B813A2A6422E02CD16055927CA20E8BAB8E81AEC4DA89756AE6543B18F009B52CD55CD53396D624C8B0D5B7C2E44BF83108FF3538280C34F3AC76E113FE6E3169184FB6D847F3474AD89A7CEB9D7D79F846492BE95A1AD095333DDEE0AEA4A518E6F55ABBAB59446AE8C7FD8A2502565608046DB3304AE6CB598745425DC93E4F8E355153DB86DC30AA412C169856EDF64F15399E14A75209D950FE4D6DC03F15918E84789B2575A94B6A9D8172B1749E576CBC156993A37B1FF692C919193E1DF4CA337764DA19FF86D1E1DD3FAECFBF4451D136DCFF759E52227722B86F357BB30ED244DDC7D56BBA3B3F8347989C1E0F20261F7A6FC0FBB1C170BAE41D97CBD27A3FD2E3AD19394B1731D248BAF5B2089ADB7676679F53AC6A69633FE5392C846B11191C6997F8FC9D66631204110872D0CD6C1AF3498CA6483FB1357D1C1F03C7A8CA5C1FD9521A071C193677112EA8F880A691964992356FBAC2A2E70BE66C40C84EFE58BF39301F86A9093674BB268A3B5628FE93F8C7A3B5E0FE78CB8C67CEF37FD74E2C84F3372E194396DBD12AFBE0C4E707C1B6F8DB332937344166DE8F4F7E095808F965D38A4F4ABDE0A308793D84D00716245274B3A42845B7F65B76734522D9C166BAAA8D87BA3424C71C70CCA3E83E4A6EFB701305E51A379F57069A641440F86B02C91C63DEAAE0F84

    --Trust certificates issued by Microsoft PKI root authority for Azure database.windows.net domains
    DECLARE @CERTID int
    SELECT @CERTID = CERT_ID('MicrosoftPKI')
    EXEC sp_certificate_add_issuer @CERTID, N'*.database.windows.net'
END
ELSE
    PRINT 'Certificate MicrosoftPKI already exists.'
GO

Then, import DigiCert PKI root-authority certificate on SQL Server:

-- Run on SQL Server
-- Import DigiCert PKI root-authority certificate trusted by Azure to SQL Server, if not already present
IF NOT EXISTS (SELECT name FROM sys.certificates WHERE name = N'DigiCertPKI')
BEGIN
    PRINT 'Creating DigiCertPKI certificate.'
    CREATE CERTIFICATE [DigiCertPKI] FROM BINARY = 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

    --Trust certificates issued by DigiCert PKI root authority for Azure database.windows.net domains
    DECLARE @CERTID int
    SELECT @CERTID = CERT_ID('DigiCertPKI')
    EXEC sp_certificate_add_issuer @CERTID, N'*.database.windows.net'
END
ELSE
    PRINT 'Certificate DigiCertPKI already exists.'
GO

Finally, verify all created certificates by using the following dynamic management view (DMV):

-- Run on SQL Server
SELECT * FROM sys.certificates

Validate the certificate

After you've created the certificates, validate the MI endpoint certificate is configured correctly.

First, determine the certificate_id of the exported MI certificate by replacing the value of <ManagedInstanceFQDN> and then running the following query on SQL Server:

-- Run on SQL Server 
USE MASTER 
GO 

SELECT name, subject, certificate_id, start_date, expiry_date 
FROM sys.certificates 
WHERE issuer_name LIKE '%Microsoft Corporation%' AND name = '<ManagedInstanceFQDN>' 
GO

Next, validate the certificate by replacing the value of <certificate_id> from the result of the previous query and then running the following query on SQL Server:

-- Run on SQL Server 

USE MASTER 
GO 

EXEC sp_validate_certificate_ca_chain <certificate_id> 
GO

A response of Commands completed successfully. Completion time: … indicates the MI endpoint certificate has been successfully validated.

If you encounter an error, then drop the certificate and follow the steps in the Get the certificate public key from SQL Managed Instance and import it to SQL Server section to re-import the certificate.

To drop the certificate, run the following query on SQL Server:

-- Run on SQL Server 

USE MASTER 
GO 

DROP CERTIFICATE [<ManagedInstanceFQDN>] 
GO

Secure the database mirroring endpoint

If you don't have an existing availability group, or a database mirroring endpoint on SQL Server, the next step is to create a database mirroring endpoint on SQL Server and secure it with the previously generated SQL Server certificate. If you do have an existing availability group or mirroring endpoint, skip to the Alter an existing endpoint section.

Create and secure the database mirroring endpoint on SQL Server

To verify that you don't have an existing database mirroring endpoint created, use the following script:

-- Run on SQL Server
-- View database mirroring endpoints on SQL Server
SELECT * FROM sys.database_mirroring_endpoints WHERE type_desc = 'DATABASE_MIRRORING'

If the preceding query doesn't show an existing database mirroring endpoint, run the following script on SQL Server to obtain the name of the earlier generated SQL Server certificate.

-- Run on SQL Server
-- Show the name and the public key of generated SQL Server certificate
USE MASTER
GO
DECLARE @sqlserver_certificate_name NVARCHAR(MAX) = N'Cert_' + @@servername  + N'_endpoint'
SELECT @sqlserver_certificate_name as 'SQLServerCertName'

Save SQLServerCertName from the output as you'll need it in the next step.

Use the following script to create a new database mirroring endpoint on port 5022 and secure the endpoint with the SQL Server certificate. Replace:

  • <SQL_SERVER_CERTIFICATE> with the name of SQLServerCertName obtained in the previous step.
-- Run on SQL Server
-- Create a connection endpoint listener on SQL Server
USE MASTER
CREATE ENDPOINT database_mirroring_endpoint
    STATE=STARTED   
    AS TCP (LISTENER_PORT=5022, LISTENER_IP = ALL)
    FOR DATABASE_MIRRORING (
        ROLE=ALL,
        AUTHENTICATION = CERTIFICATE [<SQL_SERVER_CERTIFICATE>],
        ENCRYPTION = REQUIRED ALGORITHM AES
    )  
GO

Validate that the mirroring endpoint was created by running the following script on SQL Server:

-- Run on SQL Server
-- View database mirroring endpoints on SQL Server
SELECT
    name, type_desc, state_desc, role_desc,
    connection_auth_desc, is_encryption_enabled, encryption_algorithm_desc
FROM 
    sys.database_mirroring_endpoints

Successfully created endpoint state_desc column should state STARTED.

A new mirroring endpoint was created with certificate authentication and AES encryption enabled.

Alter an existing endpoint

Note

Skip this step if you've just created a new mirroring endpoint. Use this step only if you're using existing availability groups with an existing database mirroring endpoint.

If you're using existing availability groups for the link, or if there's an existing database mirroring endpoint, first validate that it satisfies the following mandatory conditions for the link:

  • Type must be DATABASE_MIRRORING.
  • Connection authentication must be CERTIFICATE.
  • Encryption must be enabled.
  • Encryption algorithm must be AES.

Run the following query on SQL Server to view details for an existing database mirroring endpoint:

-- Run on SQL Server
-- View database mirroring endpoints on SQL Server
SELECT
    name, type_desc, state_desc, role_desc, connection_auth_desc,
    is_encryption_enabled, encryption_algorithm_desc
FROM
    sys.database_mirroring_endpoints

If the output shows that the existing DATABASE_MIRRORING endpoint connection_auth_desc isn't CERTIFICATE, or encryption_algorthm_desc isn't AES, the endpoint needs to be altered to meet the requirements.

On SQL Server, the same database mirroring endpoint is used for both availability groups and distributed availability groups. If your connection_auth_desc endpoint is NTLM (Windows authentication) or KERBEROS, and you need Windows authentication for an existing availability group, it's possible to alter the endpoint to use multiple authentication methods by switching the authentication option to NEGOTIATE CERTIFICATE. This change allows the existing availability group to use Windows authentication, while using certificate authentication for SQL Managed Instance.

Similarly, if encryption doesn't include AES and you need RC4 encryption, it's possible to alter the endpoint to use both algorithms. For details about possible options for altering endpoints, see the documentation page for sys.database_mirroring_endpoints.

The following script is an example of how to alter your existing database mirroring endpoint on SQL Server. Replace:

  • <YourExistingEndpointName> with your existing endpoint name.
  • <SQLServerCertName> with the name of the generated SQL Server certificate (obtained in one of the earlier steps above).

Depending on your specific configuration, you might need to customize the script further. You can also use SELECT * FROM sys.certificates to get the name of the created certificate on SQL Server.

-- Run on SQL Server
-- Alter the existing database mirroring endpoint to use CERTIFICATE for authentication and AES for encryption
USE MASTER
ALTER ENDPOINT [<YourExistingEndpointName>]   
    STATE=STARTED   
    AS TCP (LISTENER_PORT=5022, LISTENER_IP = ALL)
    FOR DATABASE_MIRRORING (
        ROLE=ALL,
        AUTHENTICATION = WINDOWS NEGOTIATE CERTIFICATE [<SQLServerCertName>],
        ENCRYPTION = REQUIRED ALGORITHM AES
    )
GO

After you run the ALTER endpoint query and set the dual authentication mode to Windows and certificate, use this query again on SQL Server to show details for the database mirroring endpoint:

-- Run on SQL Server
-- View database mirroring endpoints on SQL Server
SELECT
    name, type_desc, state_desc, role_desc, connection_auth_desc,
    is_encryption_enabled, encryption_algorithm_desc
FROM
    sys.database_mirroring_endpoints

You've successfully modified your database mirroring endpoint for a SQL Managed Instance link.

Create an availability group on SQL Server

If you don't have an existing availability group, the next step is to create one on SQL Server, regardless of which will be the initial primary.

Note

Skip this section if you already have an existing availability group.

Commands to create the availability group are different if your SQL Managed Instance is the initial primary, which is only supported starting with SQL Server 2022 CU10.

While it's possible to establish multiple links for the same database, the link only supports replication of one database per link. If you want to create multiple links for the same database, use the same availability group for all the links, but then create a new distributed availability group for each database link between SQL Server and SQL Managed Instance.

If SQL Server is your initial primary, create an availability group with the following parameters for a link:

  • Initial primary server name
  • Database name
  • A failover mode of MANUAL
  • A seeding mode of AUTOMATIC

First, find out your SQL Server name by running the following T-SQL statement:

-- Run on the initial primary
SELECT @@SERVERNAME AS SQLServerName

Then, use the following script to create the availability group on SQL Server. Replace:

  • <AGNameOnSQLServer> with the name of your availability group on SQL Server. A Managed Instance link requires one database per availability group. For multiple databases, you'll need to create multiple availability groups. Consider naming each availability group so that its name reflects the corresponding database - for example, AG_<db_name>.
  • <DatabaseName> with the name of database that you want to replicate.
  • <SQLServerName> with the name of your SQL Server instance obtained in the previous step.
  • <SQLServerIP> with the SQL Server IP address. You can use a resolvable SQL Server host machine name as an alternative, but you need to make sure that the name is resolvable from the SQL Managed Instance virtual network.
-- Run on SQL Server
-- Create the primary availability group on SQL Server
USE MASTER
CREATE AVAILABILITY GROUP [<AGNameOnSQLServer>]
WITH (CLUSTER_TYPE = NONE) -- <- Delete this line for SQL Server 2016 only. Leave as-is for all higher versions.
    FOR database [<DatabaseName>]  
    REPLICA ON   
        N'<SQLServerName>' WITH   
            (  
            ENDPOINT_URL = 'TCP://<SQLServerIP>:5022',
            AVAILABILITY_MODE = SYNCHRONOUS_COMMIT,
            FAILOVER_MODE = MANUAL,
            SEEDING_MODE = AUTOMATIC
            );
GO

Important

For SQL Server 2016, delete WITH (CLUSTER_TYPE = NONE) from the above T-SQL statement. Leave as-is for all later SQL Server versions.

Next, create the distributed availability group on SQL Server. If you plan to create multiple links, then you need to create a distributed availability group for each link, even if you're establishing multiple links for the same database.

Replace the following values and then run the T-SQL script to create your distributed availability group.

  • <DAGName> with the name of your distributed availability group. Since you can configure multiple links for the same database by creating a distributed availability group for each link, consider naming each distributed availability group accordingly - for example, DAG1_<db_name>, DAG2_<db_name>.
  • <AGNameOnSQLServer> with the name of the availability group that you created in the previous step.
  • <AGNameOnSQLMI> with the name of your availability group on SQL Managed Instance. The name needs to be unique on SQL MI. Consider naming each availability group so that its name reflects the corresponding database - for example, AG_<db_name>_MI.
  • <SQLServerIP> with the IP address of SQL Server from the previous step. You can use a resolvable SQL Server host machine name as an alternative, but make sure the name is resolvable from the SQL Managed Instance virtual network (which requires configuring custom Azure DNS for the subnet of the managed instance).
  • <ManagedInstanceName> with the short name of your managed instance.
  • <ManagedInstanceFQDN> with the fully qualified domain name of your managed instance.
-- Run on SQL Server
-- Create a distributed availability group for the availability group and database
-- ManagedInstanceName example: 'sqlmi1'
-- ManagedInstanceFQDN example: 'sqlmi1.73d19f36a420a.database.windows.net'
USE MASTER
CREATE AVAILABILITY GROUP [<DAGName>]
WITH (DISTRIBUTED) 
    AVAILABILITY GROUP ON  
    N'<AGNameOnSQLServer>' WITH 
    (
      LISTENER_URL = 'TCP://<SQLServerIP>:5022',
      AVAILABILITY_MODE = ASYNCHRONOUS_COMMIT,
      FAILOVER_MODE = MANUAL,
      SEEDING_MODE = AUTOMATIC,
      SESSION_TIMEOUT = 20
    ),
    N'<AGNameOnSQLMI>' WITH
    (
      LISTENER_URL = 'tcp://<ManagedInstanceFQDN>:5022;Server=[<ManagedInstanceName>]',
      AVAILABILITY_MODE = ASYNCHRONOUS_COMMIT,
      FAILOVER_MODE = MANUAL,
      SEEDING_MODE = AUTOMATIC
    );
GO

Verify availability groups

Use the following script to list all availability groups and distributed availability groups on the SQL Server instance. At this point, the state of your availability group needs to be connected, and the state of your distributed availability groups needs to be disconnected. The state of the distributed availability group moves to connected only once it's joined with SQL Managed Instance.

-- Run on SQL Server
-- This will show that the availability group and distributed availability group have been created on SQL Server.
SELECT * FROM sys.availability_groups

Alternatively, you can use SSMS Object Explorer to find availability groups and distributed availability groups. Expand the Always On High Availability folder and then the Availability Groups folder.

Finally, you can create the link. The commands differ based on which instance is the initial primary. Use the New-AzSqlInstanceLink PowerShell or az sql mi link create Azure CLI command to create the link, such as the PowerShell example in this section. Creating the link from a SQL Managed Instance primary isn't currently supported with the Azure CLI.

If you need to see all links on a managed instance, use the Get-AzSqlInstanceLink PowerShell or az sql mi link show Azure CLI command in Azure Cloud Shell.

To simplify the process, sign in to the Azure portal and run the following script from the Azure Cloud Shell. Replace:

  • <ManagedInstanceName> with the short name of your managed instance.
  • <AGNameOnSQLServer> with the name of the availability group created on SQL Server.
  • <AGNameOnSQLMI> with the name of the availability group created on SQL Managed Instance.
  • <DAGName> with the name of the distributed availability group created on SQL Server.
  • <DatabaseName> with the database replicated in the availability group on SQL Server.
  • <SQLServerIP> with the IP address of your SQL Server. The provided IP address must be accessible by managed instance.

Note

If you want establish a link to an availability group that already exists, then provide the IP address of the listener when supplying the <SQLServerIP> parameter.

#  Run in Azure Cloud Shell (select PowerShell console)
# =============================================================================
# POWERSHELL SCRIPT TO CREATE MANAGED INSTANCE LINK
# Instructs Managed Instance to join distributed availability group on SQL Server
# ===== Enter user variables here ====

# Enter your managed instance name – for example, "sqlmi1"
$ManagedInstanceName = "<ManagedInstanceName>"

# Enter the availability group name that was created on SQL Server
$AGNameOnSQLServer = "<AGNameOnSQLServer>"

# Enter the availability group name that was created on SQL Managed Instance
$AGNameOnSQLMI = "<AGNameOnSQLMI>"

# Enter the distributed availability group name that was created on SQL Server
$DAGName = "<DAGName>"

# Enter the database name that was placed in the availability group for replication
$DatabaseName = "<DatabaseName>"

# Enter the SQL Server IP
$SQLServerIP = "<SQLServerIP>"

# ==== Do not customize the following cmdlet ====

# Find out the resource group name
$ResourceGroup = (Get-AzSqlInstance -InstanceName $ManagedInstanceName).ResourceGroupName

# Build properly formatted connection endpoint
$SourceIP = "TCP://" + $SQLServerIP + ":5022"

# Create link on managed instance. Join distributed availability group on SQL Server.
New-AzSqlInstanceLink -ResourceGroupName $ResourceGroup -InstanceName $ManagedInstanceName -Name $DAGName |
-PrimaryAvailabilityGroupName $AGNameOnSQLServer -SecondaryAvailabilityGroupName $AGNameOnSQLMI |
-TargetDatabase $DatabaseName -SourceEndpoint $SourceIP

The result of this operation is a time stamp of the successful execution of the create a link request.

To verify the connection between SQL Managed Instance and SQL Server, run the following query on SQL Server. The connection won't be instantaneous. It can take up to a minute for the DMV to start showing a successful connection. Keep refreshing the DMV until the connection appears as CONNECTED for the SQL Managed Instance replica.

-- Run on SQL Server
SELECT
    r.replica_server_name AS [Replica],
    r.endpoint_url AS [Endpoint],
    rs.connected_state_desc AS [Connected state],
    rs.last_connect_error_description AS [Last connection error],
    rs.last_connect_error_number AS [Last connection error No],
    rs.last_connect_error_timestamp AS [Last error timestamp]
FROM
    sys.dm_hadr_availability_replica_states rs
    JOIN sys.availability_replicas r
    ON rs.replica_id = r.replica_id

After the connection is established, Object Explorer in SSMS might initially show the replicated database on the secondary replica in a Restoring state as the initial seeding phase moves and restores the full backup of the database. After the database is restored, replication has to catch up to bring the two databases to a synchronized state. The database will no longer be in Restoring after initial seeding finishes. Seeding small databases might be fast enough that you won't see the initial Restoring state in SSMS.

Important

  • The link won't work unless network connectivity exists between SQL Server and SQL Managed Instance. To troubleshoot network connectivity, follow the steps in Test network connectivity.
  • Take regular backups of the log file on SQL Server. If the used log space reaches 100 percent, replication to SQL Managed Instance stops until space use is reduced. We highly recommend that you automate log backups by setting up a daily job. For details, see Back up log files on SQL Server.

Take first transaction log backup

If SQL Server is your initial primary, it's important to take the first transaction log backup on SQL Server after initial seeding completes, when the database is no longer in the Restoring... state on Azure SQL Managed Instance. Then take SQL Server transaction log backups regularly to minimize excessive log growth while SQL Server is in the primary role.

If SQL Managed Instance is your primary, you don't need to take any action as Azure SQL Managed Instance takes log backups automatically.

If you want to drop the link, either because it's no longer needed, or because it's in an irreparable state and needs to be recreated, you can do so with PowerShell and T-SQL.

First, use the Remove-AzSqlInstanceLink PowerShell command to drop the link, such as the following example:

Remove-AzSqlInstanceLink -ResourceGroupName $ResourceGroup -InstanceName $managedInstanceName -Name $DAGName -Force

Then, run the following T-SQL script on SQL Server to drop the distributed availability group. Replace <DAGName> with the name of the distributed availability group used to create the link:

USE MASTER 
GO 

DROP AVAILABILITY GROUP <DAGName>  
GO

Finally, optionally, you can remove the availability group if you no longer have a use for it. To do so, replace the <AGName> with the name of the availability group and then run it on the respective instance:

DROP AVAILABILITY GROUP <AGName>  
GO

Troubleshoot

If you encounter an error message when you create the link, review the error message in the query output window for more information.

Related content

To use the link:

To learn more about the link:

For other replication and migration scenarios, consider: