This comprehensive guide explores Distributed Network Names (DNNs), an essential concept for managing AlwaysOn Availability Groups on Azure SQL Server VMs. It delineates the differences between DNNs and Virtual Network Names (VNNs), outlines the advantages of using DNNs, and provides a detailed walkthrough for setting them up using PowerShell.<\/p>\n
A DNN, or Distributed Network Name, is a specialized listener designed for AlwaysOn Availability Groups deployed on SQL Server VMs in Azure. It serves as a unified entry point for client applications, facilitating connection to the availability group regardless of the primary replica. This feature simplifies client configurations by obviating the need to manage individual IP addresses or DNS entries for each replica.<\/p>\n
While both DNNs and Virtual Network Names (VNNs) facilitate connections to AlwaysOn Availability Groups, their methodologies differ:<\/p>\n
Open a text editor, such as Notepad.<\/p>\n<\/li>\n
Copy and paste the following script:<\/p>\n<\/li>\n<\/ol>\n
param<\/span> ( [Parameter(Mandatory=$true<\/span>)][string]$Ag<\/span>, [Parameter(Mandatory=$true<\/span>)][string]$Dns<\/span>, [Parameter(Mandatory=$true<\/span>)][string]$Port<\/span> ) Write-Host<\/span> “Add a DNN listener for availability group $Ag<\/span> with DNS name $Dns<\/span> and port $Port<\/span>“<\/span> $ErrorActionPreference<\/span> = “Stop”<\/span><\/p>\n # create the DNN resource with the port as the resource name<\/span> Add-ClusterResource<\/span> -Name<\/span> $Port<\/span> -ResourceType<\/span> “Distributed Network Name”<\/span> -Group<\/span> $Ag<\/span><\/p>\n # set the DNS name of the DNN resource<\/span> Get-ClusterResource<\/span> -Name<\/span> $Port<\/span> | Set-ClusterParameter<\/span> -Name<\/span> DnsName -Value<\/span> $Dns<\/span><\/p>\n # start the DNN resource<\/span> Start-ClusterResource<\/span> -Name<\/span> $Port<\/span> $Dep<\/span> = Get-ClusterResourceDependency<\/span> -Resource<\/span> $Ag<\/span> if<\/span> ( $Dep<\/span>.DependencyExpression -match<\/span> ‘\\s*\\((.*)\\)\\s*’<\/span> ) { $DepStr<\/span> = “$($Matches<\/span>.1) or [$Port<\/span>]”<\/span> } else<\/span> { $DepStr<\/span> = “[$Port<\/span>]”<\/span> } Write-Host<\/span> “$DepStr<\/span>“<\/span><\/p>\n # add the Dependency from availability group resource to the DNN resource<\/span> Set-ClusterResourceDependency<\/span> -Resource<\/span> $Ag<\/span> -Dependency<\/span> “$DepStr<\/span>“<\/span> #bounce the AG resource<\/span> Stop-ClusterResource<\/span> -Name<\/span> $Ag<\/span> Start-ClusterResource<\/span> -Name<\/span> $Ag<\/span><\/p>\n Save the script as a\u00a0 Check the creation of your DNN listener with which should return details about the listener including its name and port number.<\/p>\n Distributed Network Names offer a robust solution for managing AlwaysOn Availability Groups in Azure SQL Server VMs. By leveraging DNNs, DBAs can optimize their setups for better scalability, simplified network management, and enhanced overall availability, making them a pivotal tool in modern cloud environments.<\/p>\n\n\n Further Reading: <\/p>\n","protected":false},"excerpt":{"rendered":" This guide explores Distributed Network Names (DNNs) for managing AlwaysOn Availability Groups on Azure SQL Server VMs. It explains how DNNs differ from Virtual Network Names (VNNs), highlights the benefits of DNNs (simplified configuration, enhanced flexibility, improved availability), and provides a step-by-step walkthrough for setting up a DNN listener using PowerShell.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[36,101,116,21],"tags":[38,122],"class_list":["post-105","post","type-post","status-publish","format-standard","hentry","category-availability-groups","category-azure","category-connectivity","category-tutorial","tag-availability-groups","tag-distributed-network-names"],"yoast_head":"\n\n
.ps1<\/code>\u00a0file, such as\u00a0add_dnn_listener.ps1<\/code>.<\/p>\n<\/li>\nVerifying DNN Creation:<\/h4>\n
select * from sys.availability_group_listeners<\/a><\/code><\/pre>\nConclusion<\/h2>\n
Configure DNN listener for availability group – SQL Server on Azure VMs | Microsoft Learn<\/a>
The Art of Resolving HADR_SYNC_COMMIT Waits in SQL Server – SQL Table Talk<\/a><\/p>\n\n\n\n