duplicated CI's by vCenter and host discovery

User370547
Giga Contributor

‎09-07-2020 02:09 AM

Hello

When discover the vCenter, we get all the VM's, ESX hosts, Templates ..... into the CMDB.
When I discover the VM's separately (unix host discover), then we get duplicate entries into CMDB.

(same name, different class - Should it be this way ? )

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Sincerely Detlef Biedermann

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Ashutosh Munot1
Kilo Patron
Kilo Patron

‎09-07-2020 07:38 AM

Hi,

That is actually true and it is not duplicate. Each VM instance has a host attached to it.


So that VM is just a instance with minimum details and when you discover that VM using OS discovery it will link this two devices meaning VM instance and then Linux Server which you see to each other. Check the relation ship you will see that there.


Thanks,
Ashutosh

srikanthnelapud
ServiceNow Employee
ServiceNow Employee

‎09-08-2020 12:55 PM

Hello,

 

@Ashutosh Munot - Thanks for sharing the information.

 

@Detlef Biedermann - Its an expected behavior and it's not a duplicate. Let me help in you in understanding why 2 entries are seen for the CIs.

Whenever you do vCenter/VMware Discovery, it pulls VMs information as well along with other resources. The VMs information which is get is pure hardware detail like CPU information, kind of VM, etc. These VMs persisted in the table - cmdb_ci_vmware_instance (VMware Virtual Machine Instance).

Now, when you do the host discovery via it's IP, the discovery process logs into that specific VM with the credentials existing/added in the system (Credential less is also done but it's conditional). The way you log into your laptop... the hardware details of the laptop represent the CI in VMware Virtual Machine Instance table and once you login to your laptop, we find what OS it is, what are the process running, etc.

Upon host discovery, it creates an entry in the Linux Server table (cmdb_ci_linux_server - If the OS of the VM is Linux flavor) or Windows Server table (cmdb_ci_win_server - If the OS of the VM is Windows flavor) with all the OS related information.

So physically though you see 2 records representing 2 CIs, logically they both together (i.e, CI in Linux Server table and VMware Virtual Machine Instance table) represents the hardware and OS detail of one single VM existing in vCenter/VMware

We represent this connection in CMDB via "Instantiates::Instantiated by" relationship so if you open the record from the VMware Virtual Machine Instance table then you'll find the relationship with Linux Server CI and vice-versa if you open the record from the Linux Server table.

 

For more information, please refer to - Server CI and VM Instance CI Relationship Understanding and Known Issues

Sushil14
Tera Contributor
In response to srikanthnelapud

‎11-09-2022 08:48 PM

Hi srikanthnelapud 

Thanks for the details, I am facing the same scenario and understand that the relationship is set between two classes so it is two CI but isn't technically one and got duplicated because of two separate class. If this is the expected behavior then did any of your customer complaining about the duplicate CI issue while doing ITOM implementation (Event Management). How are they handling this situation? 

We also forwarding event into ServiceNow from Logic Monitor and events getting confused which CI the event relates to. Generally event attributes includes hostname not the Operating system or version, so we are unable to relate this based on two class into ServiceNow. 

 

Please advice. Thanks

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