Duplicate entries in DX UIM inventory for ICMP discovered devices
Article ID: 427085
Updated On:
Products
Issue/Introduction
We have observed many duplicate entries in our environment related to devices discovered via ICMP. The devices are appearing twice.
Why am I seeing the same device twice in the UIM inventory after using ICMP to discover it?
Using MCS ICMP profiles, and devices get duplicated. Why does this happen?
Environment
- DX UIM 23.4.*
- MCS 23.4.*
- ICMP probe any version
Cause
General Notes on Device Correlation and duplication:
The first and most common reason for a device with the same hostname/IP to appear more than one time in the DX UIM inventory is when the same device is discovered "Again", "from" a different hub, and therefore with a different "origin".
When this happen the "new" device discovered with a different origin, which is different from the original one, will be added to the inventory as a separate entity, even though it will have the same IP and Origin.
Other de-correlation attributes that are not ORIGIN may contribute to create duplication. To read more about how correlation works in DX UIM read the following documents:
KB Article: How Does Discovery Correlation Work?
Documentation: Device Correlation Configuration
Notes on what causes ORIGIN based duplicate in this specific use case:
As documented in: icmp MCS Profile Type Configuration Using OC, icmp device monitoring using MCS, can start with discovering servers via discovery_agent/Discovery Wizard via OC.
This first step adds the devices into the UIM DB and visible in the inventory. The "origin" for these new devices will be the one originating from the hub hosting the discovery_agent used for finding the devices over the network.
The next step is to deploy a ICMP Setup (Enhanced) profile to designated server(s). This profile needs to be deployed to robot(s) that will have the ICMP probe installed and that are the designated "polling" servers that will monitor and collect the ICMP metrics remotely to the target devices.
The target devices can grouped by creating OC Groups on which we will later on deploy the ICMP Remote Monitoring (Enhanced) profile. When doing this, we will be asked to "select the HOST That monitors Remote Target Devices"
When the Host is selected the members of the Group to which we are deploying this profiles will be added as ICMP discovered devices ON that host's ICMP probe.
IF that selected host is sitting in a different HUB from the discovery_agent it was first discovered with, the target devices will be discovered again (as expected) BUT won't be merged into the existing ones because it will have a new ORIGIN, and duplicates will be created.
Resolution
If duplicates exist because of what described in the cause section of this article, to fix this issue:
1. delete the duplicate device in the Inventory (just do not prevent rediscovery, do not deep clean, do not delete measures and alarms).
2. Ensure that existing ICMP profiles and the when creating new ICMP Remote Monitoring (Enhanced) profiles, the host selected when defining the "select the HOST That monitors Remote Target Devices" is hosted in the same hub or that the selected host has the same ORIGIN as the one originally discovered by the discovery_agent
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