How do you setup load balancing on Windows Server 2008?
In order to setup Network Load Balancing (NLB) for a website on Windows Server 2008, one needs to ensure the following:
Preparation:
1) If the site intended for NLB deployment still only resides on one of the two servers (hosts), prepare the secondary host by installing Microsoft Web Deployment Tool (32 or 64 bit depending on your OS) on that machine first. Do the same on the default (first) host as well if it’s not already there.
2) From the default/first host go to Start->All Programs->IIS 7.0 Extensions and launch Web Deployment Command Console. Synchronize the two machines by running the following statement from within this utility:
msdeploy -verb:sync -source:apphostconfig="<site name here>" -dest:apphostconfig="<site name here>",computername=<computer name here>
3) On the secondary host, open IIS7, right-click on the site which has just been synchronized and change the IP from the default host’s IP to the secondary host’s IP by selecting Edit Bindings.
4) While in the Site Bindings window, take this time to also add the IP designated for use by the NLB cluster (the one everybody will use to access the site once NLB is deployed). Be sure to add this same IP to the Site Bindings window of BOTH host machines and restart IIS services on each, but don’t add it to your NIC’s properties as the NLB Manager will do this upon deployment automatically.
5) Verify that both host machines are now serving-up the same site when browsed to individually, using their own distinct IPs (not the designated cluster IP).
6) For internal deployments, add a Host (A) Record in DNS mapping the designated cluster IP to the designated internal name for the site. For external/production deployments, update global DNS only after the following is completed:
Deployment:
1) On the default host machine, select Start-> Administrative Tools->Network Load Balancing Manager. (Install this from the Features list if not already in place).
2) From within the Network Load Balancing Manager, right-click Network Load Balancing Clusters and select New Cluster.
3) Enter the default host machine’s name in the Host: field and select Connect. Select the IP/NIC of the machine that will be handling all external site requests; this is the NIC the Virtual Cluster IP will bind to. Select Next.
4) Set the priority of this host, as you wish for it to rank amongst all hosts yet to be added. Do not add any additional IPs under Dedicated IP addresses. Leave the Initial host state section as default (Started and unchecked). Click Next.
5) Add the designated Cluster IP address and subnet mask to the Cluster IP Address list and select Next.
6) Under Cluster IP configuration, enter the corresponding name for this site in the Full Internet name field. For Cluster operation mode, choose Multicast for virtual environments. Choose Unicast or Multicast mode for dedicated, physical server deployments. Select Next.
7) Leave the Defined port rules at their default setting and click Finish. This will create the initial cluster configuration. Once it’s done and you see, on the left side of the screen, the cluster with its single host listed underneath, green and with no hour glass, the initial configuration is complete.
8) Right click on the new cluster, not the host, and select Add Host To Cluster. Repeat steps 3 to 7, replacing the default host machine’s name/IP with the secondary host’s information instead. The designated cluster IP is of course the same as before. If you have connectivity issues connecting to the secondary host, be sure to enable the built-in "COM+ Network Access (DCOM-In)" inbound Windows Firewall rule, on both machines, as well.
9) Test the designated cluster’s virtual address either locally or from (preferably) another location. Use a temporary lmhosts file for testing purposes with a production switchover/rollout.
Network Load Balancing (NLB) is deployed!
