Run File-based Discovery

Run File-based Discovery to find all of your installed software whether it is registered or not. You can enable and configure File-based Discovery at any time using the Discovery Configuration Console.

Avant de commencer

Role required: admin

Procédure

1. Set up the PowerShell script.
   By default, the filebaseddiscovery.ps1 script has a ServiceNow signature. Its certificate chain resolves up to the VeriSign Universal Root Certification Authority which is trusted by Windows by default. Since PowerShell scripts are signed by ServiceNow publisher, add ServiceNow publisher to your trusted publisher repository.

   

   If your Execution Policy requires you to use your own certificate or if you need to make any changes to the script, re-sign the script.

   1. Navigate to the probe “Windows - File discovery.”
   2. Open the filebaseddiscovey.ps1 probe parameter.
   3. Copy the contents of the value field into a file.
   4. Make the necessary changes to the file and then remove the (old) signature block at the end of the file.
   5. Re-sign the script: https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-authenticodesignature?view=powershell-6.

      After re-signing, the file should have a new signature block at the end of it.

   6. Copy the entire file contents and replace the old value in the filebaseddiscovery.ps1 probe parameter from step b.

      Windows File-based Discovery should now run using the updated signed script.

   If you are using anti-virus software, make sure to include all of the ServiceNow Windows PowerShell scripts so the anti-virus software does not see it as a threat.

2. Activate the File-based Discovery plugin.
3. Enable and configure File-based Discovery.
   Using the Discovery Configuration Console, you can enable File-based Discovery as well as configure several components to find and manage all of your installed software.

   To avoid impacting performance for existing customers, File-based Discovery is disabled by default.

4. Configure File-based Discovery scans.
   After Discovery runs and returns file information for a CI, it will not execute File-based Discovery again on that target until the interval has expired. Since there is a performance cost when File-based Discovery performs scans, it is important to determine how frequently to scan. However, choosing a more frequent interval than Monthly is not recommended due to performance considerations.
   1. Using the Discovery Configuration Console, expand Common and then enter the maximum number of files that you want to discover.
      Remarque :

      Increasing this value can impact performance.
   2. Select the Frequency that File-based Discovery runs on the CI.
      The default is set to Monthly.
   Remarque :

   File-based Discovery does not trigger until initial Content Data Service (CDS) synchronization occurs. CDS synchronization could take approximately 24 hours for the initial set of data to be synchronized from CDS. For more information see, File Signature Normalization.

Résultats

Your File-based Discovery should run based on the configurations set.

File-based Discovery issue resolution

If you have any issues while setting up or running File-based Discovery, follow the actions listed here to help resolve them.

Issue	Cause/Action
Error message: File Discovery data not yet synced...	Allow CDS time to sync the samp_file_* tables. Check cds_client_schedule table and see if timestamp has been updated for “samp_file_*” tables.
File-based Discovery is not triggered during Discovery.	Feature has not been enabled. Check the Discovery Definition Configuration Console and ensure that File-based Discovery is enabled. Interval between scans is too long. Check the interval setting on the Discovery Definition Configuration Console.
File-based Discovery is not triggered during Discovery.	Check the Internal properties managed by the Discovery [discovery_private_properties] table for the following items. To view this table, enter discovery_private_properties.list in the navigation filter and press Enter. File_discovery.file_extensions_windows should contain a list of Windows file extensions to be scanned. File_discovery.unix_filename_timestamp should be something other than 1970 timestamp. File_discovery_windows_filename.timestamp should be something other than 1970 timestamp.
Errors in MID Server log from FileDiscoveryFilter or MID Server issue created.	Look to see if the File-based discovery inclusion list exists. The inclusion list is in the MID Server installation folder in /agent/work. If it does not exist, the sync did not succeed. Look at the MID Server record on the instance to see if a MID Server issue was created. MID Server uses the GetMIDInfo scripted soap service to synchronize the inclusion list. See if errors are generated from this script. Click the File discovery filter refresh Related Link in the MID Server record to synchronize the file names to this MID Server.
PowerShell errors	Include the script in your anti-virus software. Add ServiceNow publisher to your trusted publisher repository.