Discovery troubleshooting - exploration

In the exploration phase, you have full access to your systems and are now going to populate data in the CMDB.

About this task

There isn’t much troubleshooting to do in this phase other than from issues involving probes and sensors or access to directories, file systems, and unique commands that might not execute because of missing permissions. These issues can all be found in the Discovery log.

Processing

All work is processed in and out of the ECC Queue and is identified on each Discovery status record.

Discovery troubleshooting ECC queue
Use the ECC Queue to identify the four phases of Discovery that are executed for each device: port scanning (Shazzam probe), classification, identification, and exploration. The ECC Queue has two important columns for tracking the processing of a Discovery:
Table 1. ECC queue columns
Column Values
State
  • Ready
  • Processing
  • Processed
  • Error
Queue
  • Output
  • Input

Output errors are rare and can result from major changes to the moving parts of your Discovery application. Input error records are not uncommon, especially when Discovery is using custom probes and sensors. Input errors usually mean that the system could not parse the XML data returned with the sensor script. In any error response, the details in the input record of the returned probe provide information about the source of the error.

To view error results:

Procedure

  1. Navigate to Discovery > Status.
  2. Open the record for the discovery that failed.
  3. Select the ECC Queue tab.
  4. Open the output or input record that shows a State of error.
  5. Click the icon in the Payload field to format the payload in XML.
  6. Search the payload for error messages.
    The same error message also appears in the Discovery Log.
    Note: Confirm the input processing information. Any work that needs to be done to resolve issues in this queue must be completed by ServiceNow Technical Support.

    Process Flow

    An overall Discovery process follows the same path each time for each probe as illustrated in this diagram.

    MID server probe simple diagram

    ECC Queue States

    Table 2. ECC queue states
    State/Queue Description
    output - ready A probe is created and queued up for the appropriate MID Server.
    output - processing The MID Server has collected the request from its queue and launched the probe.
    input - ready The probe has completed its task.
    output - processed The input - ready (sensor) record has been created.
    input - processing The probe has delivered its payload to the sensor.
    input - processed The data from the sensor has been entered into the CMDB.

    Action

    The best way to identify any bottlenecks and processing issues is to identify where the processing is taking place. The following are some common scenarios with possible solutions:
    • Schedule sits in a starting state:

      Is the System Scheduler backed up behind other system jobs? Is it running?

    • Schedule is active but the Shazzam probe is in the output - ready state for longer than 15 seconds:

      Check the state of the MID Server. It is most likely down or requires a restart.

    • Schedule has been running and is active, but there is no movement of Output probes, and the process seems stalled:

      Ensure that you are giving the probes adequate time for processing.

      Check the state of the MID Server. It could be down or require a restart.

    • Schedule has been running and is active, but there is no movement on the input probes, specifically the input – ready entries:

      Confirm that the scheduler is running and is not backed up behind other system jobs.

      To view scheduler statistics, navigate to System Diagnostics > Stats > Stats.

      Discovery troubleshooting scheduler