Can I use SNMP for Linux discovery

Ann B_
Tera Contributor

‎10-19-2018 07:48 AM

SNMP credentials have been configured for Linux servers. When I choose "test credential" it works and says successful. When I run discovery it fails and says "no valid SSH credentials". How can I force discovery to use SNMP credentials for some Linux servers?

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DaveHertel
Kilo Sage
Kilo Sage

‎10-19-2018 10:22 AM

In this case, I'd recommend setting up a Behavior to force a Disco job to only use SNMP for the desired Linux box(es). 

https://docs.servicenow.com/bundle/london-it-operations-management/page/product/discovery/concept/c_DiscoveryBehaviors.html

You could also consider changing the Classification Priorities used for Port Probes, but this affects ALL discoveries on the platform.  By default SSH is a higher priority (i.e. used first) vs. SNMP when hitting a Linux box.  Which is why you are seeing the results you described... Before going this route and changing the priority order, be sure you really want SNMP to be preferred vs. SSH for ALL Linux/Unix/Other in your environment.

 

Hope this helps...

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doug_schulze
ServiceNow Employee
ServiceNow Employee

‎10-19-2018 10:54 AM

We discover Linux systems exclusively with SSH (OOB) if you want to use SNMP you have to build an entire structure of classifiers, identifiers and exploration probes using SNMP.

DaveHertel
Kilo Sage
Kilo Sage
In response to doug_schulze

‎10-19-2018 11:20 AM

Exclusively eh?  Well, learn something new everyday.  Thanks Doug - I assumed (incorrectly it seems) that there were snmp probes for unix too.  Thx for tips!

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doug_schulze
ServiceNow Employee
ServiceNow Employee
In response to DaveHertel

‎10-19-2018 11:42 AM

Yeah, your remembering 'way back'.  We did at one time have compute devices in the SNMP classification till we learned that we couldn't get the good stuff to build relationships and such so they remained just a 'shell' of a CI. Was kinda of a catch all till our friends could get ssh credentials.  Caused so many headaches that I was finding myself just disabling the SNMP compute classifiers and focusing on getting the right SSH credentials.   Over time they were removed and now a part of discovery lore..