Probes vs Patterns

[pauladams]

Hello,

I am trying to understand the advantages and disadvantages of using Patterns vs Probes for Discovery.

Can you please shed some light on this?

Also, if patterns are a more preferred way to do Discovery, do we have patterns available as a substitute for all the probes?

Thanks

-Pa

[chuckm]

As JordanLind said, the CI Classification is the location where you set whether you want to used Probe-based discovery or Pattern-based discovery.

To give an example
To configure Probe-based discovery for switches, select the Standard Network Switch Classifier (Discovery Definition->CI Classification->SNMP). In the Triggers probes tab select the Edit button and select the following probes:

To configure Pattern-based discovery for switches, select the Standard Network Switch Classifier (Discovery Definition->CI Classification->SNMP).  In the Triggers probes tab select the Edit button and select the single probe:

[pauladams]

Thank you Jordan and Chuck.

I was looking at the OOB Windows 2016 classifier and under the Triggers Probes related list, I see it has 2 probes for Identification Phase - one a horizontal pattern and the other a Multiprobe.

Also, it has a dozen probes for the Exploration phase. I thought once we have a pattern for Identification it will also do the exploration, without an additional phase.

Can you please explain and help me understand the following?

1) Why are there two probes for the Identification phase?

2) Why are there multiple probes for the exploration phase? Why couldn't the same horizontal probe be used for both Identifcation & Exploration?

Thanks

-Pa

[chuckm]

Answer to Question #1
What you are seeing under the Triggers probes tab for the Windows 2016 Server Classifier is a mixture both Probe-based and Pattern-based Identification discovery probes. Either you have Probe-based discovery set to active or Pattern-based discovery set to active. Only one Identification Probe can be active at one time.  In the example you are showing, the Pattern-based Identification probe is set to true.

[Andrew Westerv4]

ServiceNow Docs explains the different activities kicked off from the classifier based on the version of Discovery you are using: patterns or probes. As I mentioned previously, not all functionality of Discovery has been converted and that is why you still require the ADM probe with the Horizontal Pattern.

The main thing to notice is that most of your probes are inactive and in this case you are using the latest version Pattern-based Discovery for your Win2016 servers.

Technically, the Horizontal probe replaces all of the functionality of the old probes and sensors for both Identification and Exploration to do it within a single script. With the movement to Patterns, the exploration phase seems to be heading towards the phase for custom Discovery enhancements that partners and customers can add on to the process.

https://docs.servicenow.com/bundle/madrid-it-operations-management/page/product/discovery/reference/...

[chuckm]

As Andrew mentioned, depending on the type of discovery (Probe-based or Pattern-based) requires setting the Active flag on the probe.  Instead of having a tab for Probe-based discovery and a tab for Pattern-based discovery, both are grouped together in the Triggers probes tab.

To clearly separate out the difference between the two types of discovery, the following is a Windows 2016 Server Classifier configuration for Pattern-based discovery.

And a Windows 2016 Server Classifier configuration for Probe-based discovery.

Note:  The probes grouped together in purple are functionality that didn’t get incorporated into the Windows OS – Servers pattern and the active attribute is set to true for both Probe-based and Pattern-based discovery.