Wednesday, August 19, 2015

Powershell: Automating AWS Route 53 Record Sets

Speaking of Cloud Environment where auto - scaling, self-healing servers have replaced the more conservative way of scaling – We can’t have classic manual way of DNS management.  I.e. Each new instance launched by auto scaling group should assign itself a human-readable hostname. In these cases Instance itself should be equipped enough to add its corresponding entry under Route 53. We can make use of Route53 and PowerShell to impalement this automation from Windows machine.

What Is Route 53?

Route 53 is a complete DNS solution provided by Amazon that lets you control every aspect of the name resolution process for your domain. You choose a registrar to reserve your domain, as common practice they often be managing all the DNSs for your domain. But if you are looking for more granular control over this Route 53 is one of the services you should be interested in. A details description of Route 53 is beyond the scope of this article, but you can check at AWS Route 53

Automation Script

I have wrapped the whole script into a function.We have used PowerShell V3 , consider that as prerequisite.Having Amazon cmdlets loaded should be done before expecting it to work.Pointers related to it's functioning :
  • Execution of this script will only materialize given working pair of Secret Key & Access Key
  • It validates the Record type with values mentioned under ValidateSet
  • If wait is specified, the function will wait until AWS confirms that the change is in sync. To be more specific it verifies whether entry has been propagated under specified Zone. By default i have kept it as false
  • If you have mentioned wait as true, waitinterval specifies the interval in milliseconds between each polling
  • Every parameter can be overridden why calling this function
Function Create-AwsRoute53Record
{
    [CmdletBinding(SupportsShouldProcess=$true)]
    Param (
                [String]$AccessKeyID="****************",
        [String]$SecretAccessKeyID="*****************",
                [String]$Region="us-east-1",
                [Parameter(Mandatory=$true)] $Zone,
               [ValidateSet("A", "SOA", "PTR", "MX", "CNAME","TXT","SRV","SPF","AAAA","NS")]
                [String]$RecordType,
               [Parameter(Mandatory=$true)]
                [String]$Name,
              [Parameter(Mandatory=$true)]$Value,
               $TTL,
               $wait = $false,
              [int]$waitinterval = 1000

        )
   
    Process
    {
     Set-AWSCredentials -AccessKey $InfoObject.AccessKey  -SecretKey $InfoObject.SecretKey
    Set-DefaultAWSRegion -Region $region
    $zoneEntry = (Get-R53HostedZones) | ? {$_.Name -eq "$($Zone)."}
 
$hostedZone = $zoneEntry.Id
        if (@($zoneEntry).count -eq 1) {
                $Record = new-object Amazon.Route53.Model.ResourceRecord
                $record.Value = $Value
                 #add the trailing dot
        if (!($Name.EndsWith(".")) -and $Name)
            {$Name += "."}

        $ResourceRecordSet = New-Object Amazon.Route53.Model.ResourceRecordSet
        $ResourceRecordSet.Type = $RecordType
        $ResourceRecordSet.ResourceRecords = $Record
        $ResourceRecordSet.Name = $Name
        $ResourceRecordSet.TTL = $TTL


        $change = New-Object Amazon.Route53.Model.Change
        $change.Action = "Create"
        $change.ResourceRecordSet = $ResourceRecordSet
     
        $Changes = (New-Object -TypeName System.Collections.ArrayList($null))
        $Changes.Add($Change)

        Try
        {
            $result = Edit-R53ResourceRecordSet -ChangeBatch_Changes $Changes -HostedZoneId $hostedZone
         
        }
        Catch [system.Exception]
        {
            Write-error $error[0]
        }
     
        if ($result)
        {
            if ($wait)
            {
            #Keep polling the result until it is no longer pending
            Do
                {
                    #get change status
                    if ($SecondPoll)
                        {Start-Sleep -Milliseconds $waitinterval}
                   $status=Get-R53Change -Id $result.Id
                    $SecondPoll = $true
                    Write-verbose "Waiting for changes to sync. Current status is $($status.Status.Value)"
                }
            Until ($status.Status.Value -eq "INSYNC")

     
            }
     
            $Status
        }
     }
  }
}

Script Execution

Below we have a sample execution which captures the Public IP of AWS instance ,  and subsequently add it to specified Zone as A Name record Type.

# Change the values as per your specification i.e Zone , Name , RecordType and TTL. Wait is enabled to provide added control.
$LocalIP = Invoke-RestMethod -Uri http://169.254.169.254/latest/meta-data/local-ipv4 -Method Get
$LocalIP=$LocalIP.Trim()
Create-AwsRoute53Record -Zone xyz.com -RecordType A -Name testing.xyz.com  -Value $LocalIP -TTL 500  -wait $true

3 comments:

  1. Thanks for providing this informative information you may also refer
    http://www.s4techno.com/blog/2016/07/11/awk-scripting/

    ReplyDelete
  2. Thanks for providing this informative information you may also refer.
    http://www.s4techno.com/blog/2016/02/04/increase-the-maximum-number-of-simultaneous-users-to-log-in-to-linux-server-using-ssh/

    ReplyDelete
  3. thanks for providing such a simple information with program AWS Online Training Bangalore

    ReplyDelete