Update or create a DNS CNAME record

After you properly configure SPNs for your file system, you can cut over to Amazon FSx by replacing each DNS record that resolved to the original file system with a DNS record that resolves to the default DNS name of the Amazon FSx file system.

The dnsserver and activedirectory Windows modules are required to run the commands presented in this section.

To install the required PowerShell modules

1. Log on to a Windows instance joined to the same Active Directory that your Amazon FSx file system is joined to as a user that is a member of a group that has DNS administration permissions (AWS Delegated Domain Name System Administrators in AWS Managed Microsoft AD, and Domain Admins or another group to which you've delegated DNS administration permissions in your self-managed Active Directory).

   For more information, see Connecting to Your Windows Instance in the Amazon EC2 User Guide.

2. Open PowerShell as administrator.

3. The PowerShell DNS Server module is required to perform the instructions in this procedure. Install it using the following command.

   Install-WindowsFeature RSAT-DNS-Server

To update or create a custom DNS name to your Amazon FSx file system

1. Connect to your Amazon EC2 instance as a user that is a member of a group that has DNS administration permissions (AWS Delegated Domain Name System Administrators in AWS Managed Active Directory, and Domain Admins or another group to which you've delegated DNS administration permissions in your self-managed Active Directory).

   For more information, see Connecting to Your Windows Instance in the Amazon EC2 User Guide.

2. At the command prompt, run the following script. This script migrates any existing DNS CNAME records to your Amazon FSx file system. If none are found, it creates a new DNS CNAME record for the DNS alias alias_fqdn that resolves to the default DNS name for your Amazon FSx file system.

   To run the script:

   • Replace alias_fqdn with the DNS alias that you associated with the file system.

   • Replace file_system_DNS_name with the DNS name Amazon FSx has assigned to the file system.

   $Alias="alias_fqdn"
   $FSxDnsName="file_system_dns_name"
   $AliasHost=$Alias.Split('.')[0]
   $ZoneName=((Get-WmiObject Win32_ComputerSystem).Domain)
   $DnsServerComputerName = (Resolve-DnsName $ZoneName -Type NS | Where Type -eq 'A' | Select -ExpandProperty Name) | Select -First 1
   Add-DnsServerResourceRecordCName -Name $AliasHost -ComputerName $DnsServerComputerName -HostNameAlias $FSxDnsName -ZoneName $ZoneName
   

3. Repeat the previous step for each DNS alias that you associated with the file system in Step 1.

You've now added a DNS CNAME value for your Amazon FSx file system with the DNS alias. You can now use the DNS alias to access your data.

Note

When updating a DNS CNAME record to point to an Amazon FSx file system previously pointed to another file system, clients might not be able to connect with file system for a brief period of time. When the client DNS cache refreshes, they should be able to connect using the DNS alias. For more information, see Can't access the file system using a DNS alias.