As you can see on the Virtual PC Guy’s WebLog it’s not so easy to configure NLB within virtual machines, that run in Virtual PC. I needed a small test environment, to check some SharePoint deployment issues. When you just need such small environments for test purposes, I think this will work fine using DNS round robin. In my test environment I have 3 virtual machines:
1. Domain controller and SQL Server (testlab-dom-sql.testlab.local)
2. IIS and SharePoint Services as node 1 (wss1.testlab.local)
3. IIS and SharePoint Sercices as node 2 (wss2.testlab.local)
Within my DNS in the test environment I added two A-records for a host called intranet, pointing to the IP addresses of my two WSS-hosts.
To have a "real" load balancing in this environment, you need to set the TTL of the a-records to 0. You can do that by switching to "Advanced View" in your DNS-console.
Now, you can edit the TTL-value, when you show the properties-dialog of your a-records:
Set the values in the TTL-field to "0:0:0:0", that is 0 seconds.
When you now run an IPCONFIG /FLUSHDNS, and after that, more then one PING to your a-record, you will see, what the IP address is rotating.
With these settings, you can simulate network load balancing in your test environment in Virtual PC 2007.