Service Manager management servers in NLB

June 13, 2011 at 2:31 pm in Service Manager by kurtvh


The following procedure will guide you through the installation and configuration of the Network Load Balancing functionality with multiple Service Manager management servers.

Network load balancing in Windows Server 2008 lets you to configure a pool of computers so that they take turns responding to requests. In Service Manager, the initial Service Manager management server you deploy is the server that processes workflows. You can deploy additional management servers to provide fail-over for a failed initial management server and to provide load balancing for handling Service Manager console.

As a minimum, you have to deploy an initial Service Manager management server, the management server that hosts the workflow processes, and at least one additional Service Manager management server. You can always install more management servers in your environment, for example to have a dedicated workflow mgmt server, and exclude them from the NLB cluster.


Installation information of the SCSM environment can be found here:

Installation of the NLB feature in server 2008 (R2):

  • Click Start, click Administrative Tools, and then click Server Manager. In the Features Summary area of the Server Manager main window, click Add Features.
  • In the Add Features Wizard, select the Network Load Balancing check box and confirm the installation.
  • Click Install.


To create a new NLB cluster

  • To open Network Load Balancing Manager, click Start, click Administrative Tools, and then click Network Load Balancing Manager.
  • Right-click Network Load Balancing Clusters, and then click New Cluster.
  • To connect to the host that is to be a part of the new cluster, in the Host text box, type the name of the host, and then click Connect.
  • Select the interface that you want to use with the cluster, and then click Next. (The interface hosts the virtual IP address and receives the client traffic to load balance.)


  • In Host Parameters, select a value in Priority (Unique host identifier). This parameter specifies a unique ID for each host. The host with the lowest numerical priority among the current members of the cluster handles all of the cluster’s network traffic that is not covered by a port rule. (You can override these priorities or provide load balancing for specific ranges of ports by specifying rules on the Port rules tab of the Network Load Balancing Properties dialog box. )


  • Click Next to continue.
  • In Cluster IP Addresses, click Add and type the cluster IP address that is shared by every host in the cluster. NLB adds this IP address to the TCP/IP stack on the selected interface of all hosts that are chosen to be part of the cluster.


  • Click Next to continue.
  • In Cluster Parameters, select values in IP Address and Subnet mask. Type the full Internet name that users will use to access this NLB cluster.
  • In Cluster operation mode, click Unicast to specify that a unicast media access control (MAC) address should be used for cluster operations. In unicast mode, the MAC address of the cluster is assigned to the network adapter of the computer, and the built-in MAC address of the network adapter is not used. It is recommended that you accept the unicast default settings.


  • Click Next to continue.
  • In Port Rules, click Edit to modify the default port rules. SCSM console make connection to port 5724. In this example only this network traffic is load balanced.


  • Wait until the NLB configuration is set on the first NLB member
    • Review log entries below the NLB mgmt console.
    • Status of the first NLB cluster member should be “Converged”.
  • To add more hosts to the cluster, right-click the new cluster, and then click Add Host to Cluster. Configure the host parameters (including host priority, dedicated IP addresses, and load weight) for the additional hosts by following the same instructions that you used to configure the initial host. Because you are adding hosts to an already configured cluster, all the cluster-wide parameters remain the same.


  • Same procedure, wait until the NLB configuration is set on the first NLB member
    • Review log entries below the NLB mgmt console.
    • Status of the first NLB cluster member should be “Converged”.

Job done, in normal cases you should be able to connect the mgmt console to the virtual NLB name.


Some attention points that can help debugging failure of connection.

  • Security rights, of course you need to have the needed rights in SCSM to connect. No special configuration on this topic. If you can connect to the physical name you should also be able to connect to the virtual name.
  • Network issues can block the connection to the management servers. Work together with the network team to solve firewall,switch,… issues.
  • You need to manually configure the DNS A record for resolving the virtual name.
  • SPN registration: additional Kerberos SPN registration for the virtual NLB cluster name to the SDK account is required to make Kerberos working in the clustered environment. (MSOMSdkSvc/Netbios name & FQDN – Otherwise NTLM authentication is used)

Have fun,

Kurt Van Hoecke

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