18.2.1 Prerequisites for setting up application failover

For application failover to work successfully, the NNMi management servers must meet the following requirements:

• Only a configuration in which NNMi is used alone is supported.

  A configurations in which NNMi is linked to another related program product, such as JP1, is not supported. In such a case, use an HA configuration using cluster software.

• It must be possible to resolve the host name and IP address of the active server and of the standby server at both NNMi management servers.

• On the network, all IPv4 addresses of both NNMi management servers must not overlap.

• Both NNMi management servers must be running the same operating system. For example, if the active server's operating system is Microsoft^(R) Windows Server^(R) 2012 R2 Datacenter, the standby server's operating system must also be Microsoft^(R) Windows Server^(R) 2012 R2 Datacenter.

• Both NNMi management servers must be running the same NNMi version. The NNMi patch levels must also be the same on both servers. For example, if NNMi 12-00 is running on the active server, the identical NNMi version, NNMi 12-00, must be on the standby server.

• The system password must be the same on both NNMi management servers.

• Do not completely disable HTTP access to NNMi before configuring application failover. For details, see 21.18 Configuring NNMi to require encryption for remote access. After successfully configuring the application failover cluster, you can disable HTTP and other unencrypted access.

• For an installation on Windows, NNMi must be installed in the same directory in both NNMi management servers and the %NnmDataDir% and %NnmInstallDir% system variables must be set to identical values on both servers.

• Both NNMi management servers must have identical licensing attributes (number of nodes managed, and whether NNMi or NNMi Advanced is used). For example, the node counts and licensed features must be identical.

  Important

  The standby server must also have the identical license.

• Do not enable application failover until NNMi is in an advanced stage of initial discovery. For details, see 6.4 Evaluating discovery.

• For application failover to function correctly, the active and standby servers must have unrestricted network access to each other. Any software that locks files or restricts network access can cause NNMi communication problems. Configure these applications to ignore the files and ports used by NNMi.

• The active server and the standby server must be able use all of the IPv4 addresses of the NIC used for cluster communication to communicate with the other NNMi management server for which application failover is configured. If there is any IPv4 address that cannot be used to communicate with the other management server, application failover configuration might fail, or the behavior of a configured application failover environment might become corrupted. For details on how to specify the NICs to be used for cluster communication, see 18.3.3 Setting application failover communications.

• We do not recommend that you set up a firewall between the active and standby servers. When setting up a firewall, configure the systems such that both servers can use all ports for communication.

• To run a firewall in an NNMi management server, permit communication between processes in the local server and communication with remote servers at all ports. Application failover performs communication dynamically using any available port.

  • If you are using a firewall that permits communication on a process-by-process basis (such as Windows Firewall), permit communication by the cluster manager (nnmcluster.exe).

  • If you are using a firewall that permits communication on a port-by-port basis, permit the following types of communication:

    IP addresses: All IP addresses assigned to the local server and remote servers

    Ports: All ports

• The same password must be set for the NNMi databases on both the active and standby servers.

  If you have changed the password for an NNMi database, set the same password on all servers before you start configuring application failover.

If all these conditions are satisfied, complete the steps shown in 18.3 Configuring NNMi for application failover. For details, see E. List of Ports Used by NNMi.

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