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Setting up NLB

While infrastructure changes are required by the system, each environment is different and has its peculiarities which you must consider. Modifying the infrastructure could have unforeseen results if the changes are not appropriately understood or managed. Given the broad spectrum of underlying infrastructure utilized, it is recommended that a panel or committee with appropriate skill in each area concerned be assembled to outline the underlying infrastructure changes and gauge the impact of the required changes.

It is important to set up the Network Load Balancing (NLB) clusters before installing the product. It is also important to test that the cluster is performing correctly prior to installing the product as an incorrectly configured cluster can cause issues when using the product, and it adds a layer of complexity to troubleshooting.

For more information on the deployment of the product components in a Farm/NLB topology see the topic Farm / NLB Topologies.

The following sections describe how to configure software and hardware load balancing.

Windows Network Load Balancing Manager

Configuring Network Load Balancing (NLB) is an advanced task. Only an administrator who knows the topology of the network and the product should perform the configuration. Use these steps as a guide, as your system may require additional configuration due to different hardware and software compatibilities, and the configuration of your product services (such as the server, the SmartForms server, and APIs). You can use various software and hardware load-balancing solutions with the product. These steps are the Windows software solution, but the same principles apply to any solution.

When configuring a cluster, follow the below steps:

Open Network Load Balancing Manager (nlbmgr.exe) (Start > All Programs > Windows Administrative Tools > Network Load Balancing Manager, or Start > Run > nlbmgr.exe).
Add a New Cluster (right-click on Network Load Balancing Clusters and select New Cluster).
On the Connect page, connect to the first host in the cluster and select the appropriate connection as the interface. If the server has multiple network adapters, many interfaces may be displayed. Be sure to select the appropriate network adapter from the list and click Next.
On the Host Parameters page, select the host priority, add the host IP address and subnet mask, select the initial host state and click Next.
On the Cluster IP Addresses page, add in any additional IP addresses that the cluster can be accessed from, and click Next.
In the Cluster Parameters window, enter the appropriate IP address, subnet mask, full Internet name, and cluster operation mode, and click Next.
On the Port Rules page, edit the existing rule to use the appropriate affinity. See the notes below for recommendations based on the cluster type. Click Next to continue.
To add a second node to the cluster, right-click on the newly created cluster and select Add Host to Cluster.
Connect to the second host, and make sure to select the appropriate interface.

Considerations

This list of considerations applies to all load balancing solutions. Specific settings may be named differently in other solutions, but the principles are the same.

The product server is a stateless machine so on a product server cluster, no affinity is necessary per session.
For server clusters other than the product server, such as for system sites, use a Unicast operation mode and set the affinity to Single. Ensure that the web pages retain IP affinity to the web server during the session.
In some cases, the Network Load Balancing Manager console times out before the second node is configured. If that happens, right-click the cluster and select Refresh. You should see all the nodes in a Converged state. Make sure that your cluster is configured correctly before starting the installation.
When using the Unicast operation, you need at least two network adapters.
Set up the NLB configuration to allow traffic on the Workflow (default of 5252) and server (default of 5555) ports.
Cookie affinity cannot be used with the product.
Sometimes a newly created NLB cluster FQDN is not populated in DNS. You should manually add the cluster FQDN entry to the DNS for better network routing. For example, a NLB cluster named "Fubar.gotham.local" is created with IP 10.0.1.32, ensure this is added in the DNS forward lookup zone for that domain. Also add the NLB cluster name to the host file for each node in the cluster to prevent ambiguous network calls. For example, in the node’s hosts file, define the IP of "Fubar.gotham.local" as localhost.

Any client code that calls the product client API may require session error handling. The SmartForms server does this automatically, but if you have custom code that uses the product client API, you must plan for and handle session errors.
Given the broad spectrum of underlying infrastructure utilized, We recommend that you assemble a panel or committee with appropriate skill in each area concerned to outline the underlying infrastructure changes and gauge the impact of the flow of sessions and changes necessary to make sure the network traffic is handled correctly. Contact Nintex Services if you need additional help during this exercise.

For information on troubleshooting NLB and the product, see the NLB Troubleshooting topic.