This documentation supports the 21.05 (12.2) version of BMC Discovery.

To view an earlier version of the product, select the version from the Product version menu.

Troubleshooting duplication of hosts due to changed identity

If BMC Discovery determines that the characteristics of a host node have changed significantly, it creates a new host node. The UI displays a message, The endpoint used to discover this host now corresponds to a different hostThe old host eventually ages out according to the aging parameters set in the system. However, until the old host node ages out, the old and new host nodes coexist in the system, causing a duplication. Use the following troubleshooting sections to find such hosts whose identity has changed, and learn how to delete the old host nodes in BMC Discovery and CMDB.

For information about creating host nodes, see Host node, and for information about setting the aging parameters, see Configuring model maintenance settings.

Issue symptoms

When the old and new host nodes coexist in the system, certain reports display multiple records for the same Configuration Item (CI). This is misleading because each CI must be represented by a single record.

Scope

This issue impacts all the versions of BMC Discovery.

Resolution

You can resolve this issue in two stages. You must first identify the old hosts in the system from the Reports UI and then delete such hosts. Perform the steps listed in the following sections.

Stage 1: Identify the old hosts

  1. Log in to the BMC Discovery UI and go to Explore > Reports.
  2. Select the report titled, Devices with Endpoint Identity Change.
    The report displays a list of IP addresses for which the most recently discovered device is different from the device previously discovered on the same IP address. This difference may be due to several reasons, such as the previous device had a new IP address, it was decommissioned, or its properties changed so much that it appears to be a different device.

Stage 2: Delete the old hosts

Important

If you attempt to delete a large number of hosts at a time, such as more than 500 hosts, BMC Discovery handles your request in batches of 100 hosts at a time. For some hosts, each deletion may trigger changes in their related nodes. If these changes are occurring alongside scanning, it may adversely impact the performance of  BMC Discovery and the deletion may take longer to complete.

Perform one of the following steps to delete the identified old hosts:

  • If continuous sync is enabled for CMDB, select all the items listed in the report, and from the Actions list, select Destroy.
    A delete record notification is sent to CMDB, and the old host CI is marked as deleted in CMDB. 
  • If continuous sync is not enabled for CMDB, perform the following steps:

    • Save the list of hosts and then run the following query:

      Search FLAGS(include_destroyed, exclude_current) Host show name,friendlyTime(destructionTime(#)
    • Select the hosts from the saved list, and from the Actions list, select Sync with CMDB.  


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