Exclude IP Address from Discovery in Reconciliation Rules

[Henrik Jutterst]

Background

We're setting up Discovery for a customer and looking through the Reconciliation Rules for Servers and the extending classes. For the moment before we can start running Discovery on a broad range of IPs we need to keep some fields before we move over 100% to Discovery.

I've set up Reconciliation Rules for IP Address field to only be updated by my custom source at the moment. Or at least that it should have the highest priority.

Issue

When are running Discovery now on an example host, we see that IP Address is overwritten by ServiceNow Discovery even though it should not do so.

At least to my mind, the Reconciliation Rules looks correct. but since it's not doing what I'm looking for, I think I need some guidance is this issue. If there's a new server found and the IP Address is blank, it's Ok for ServiceNow Discovery to write to the record, but if there's already a value by my desired source, Discovery should not modify it.

Please see screen shots:

For the Second (middle) rule:

But even though this I can see that record is being updated by Discovery.

Record History:

I don't want Discovery to update this field

Edit:

I've done some modifications to the first rule now so Order is 90,91,92 instead of 90,90,90.

In the Middle/second rule, I've added to update all fields except IP Address now. But still ServiceNow Discovery keeps updating IP Address on Discovery of CI.

[Henrik Jutterst · Accepted solution]

Ok so it turns out that IP Address is a bit different then standard fields on CMDB Server and the extending classes. There was no real issue with the Reconciliation Rules for that matter, but that IP Address have some OOB differences.

So a colleague of mine fond that there is a Discovery Property called "glide.discovery.exclude_ip_sync_classes" for this matter. So by adding cmdb_ci_server to the comma separated list in the property, IP Address field is not overwritten by Discovery.

ServiceNow Docs - Discovery properties 

Defines CI classes whose IP addresses should not be substituted if the address returned by Discovery does not match one of the devices' NICs. Use a comma separated list to define multiple classes. By default, the system uses the management IP of a load balancer returned by Discovery in the CI record, rather than substituting it for the IP address of one of the load balancer's NICs.

• Type: string
• Default value: cmdb_ci_lb

So adding the value like this, solved the issue for the field to not being overwritten.