Configure Discovery

To set up Discovery and configure it to update the CMDB accurately, perform the following tasks in the order in which they appear.

Before you begin

Role required: Admin

Procedure

  1. Meet prerequisites.
    1. Grant Discovery role: Verify that users who are expected to configure and execute Discovery in your network have the discovery_admin role.
      This role grants access to the tables in the Discovery application.
    2. Select a MID Server host: Designate a computer to host the MID Server.
    3. Gather credentials: Gather the login credentials that the MID server must use to access the devices it is expected to discover.
    4. Select IP Address Ranges: Determine the IP addresses that Discovery must scan.
      In a very complex network, it is good practice to group IP ranges into a Range Set, which is reusable for different schedules. Discovery will not scan anything outside of these ranges.
  2. Enable the Discovery plugin.
    For information about purchasing a subscription, see Activate Discovery.
  3. Deploy MID Servers.

    Install one or more MID Servers on physical or virtual servers that meet the minimum requirements and configure them to communicate with the appropriate ServiceNow instance.

    A best practice is to install at least two MID Servers at first and assign them to different schedules and IP ranges to help complete discoveries quicker. Dedicating MID Servers to a particular task with Discovery Behaviors can also improve performance.

  4. Ensure MID Server connectivity. Open the instance and navigate to Discovery > MID Servers.

    If the new MID Servers are configured properly, they will appear in the list of MID Servers.

    If a MID Server does not appear as a choice in the instance, perform the following checks in the MID Server:
    • Ensure that the URL in the Configuration Parameters related list provided is correct.
    • If the MID Server is installed on Windows, make sure the ServiceNow MID Server service is configured properly with the correct logon credentials and is running.
    • Check the MID Server log for errors.
      • UI: Navigate to Discovery > MID Servers > [MID Server] > Logs.
      • MID Server Host: Navigate to the agent\logs\agent0.log0 directory.
    • If Basic Authentication is enabled, a username and password must be provided.
    • The MID Server might not have outbound access on port 443 (SSL) or a proxy server might be preventing TCP communication to the instance.
    • Make sure that no firewalls are blocking communication between the MID Server and the instance.
  5. Add credentials. Set the Discovery Credentials on the instance for all the devices in the network - Windows and UNIX computers, printers, and network gear.
    Credentials for Windows devices (using the WMI protocol) are provided by the logon configured for the MID Server service on the Windows server host. Credentials for UNIX, vCenter, and SNMP must be configured on the instance. Discovery will automatically figure out which credentials work for a particular computer or device.
  6. Define and run Discovery schedules.

    The Discovery Schedule is the control point for running discoveries. The schedule controls when Discovery runs, defines the MID Server to use, the type of Discovery that should run, and the IP addresses to query. Create as many schedules as necessary, using different types of discoveries, and configure them to run at any time. Let Discovery run on its configured schedule or manually execute Discovery at any time. These schedules can be set up in a variety of ways, including a single schedule for the entire network or separate schedules for each location or VLAN.

    If you do not know the IP address to scan in your network, run a Network Discovery first to discover the IP networks. Once discovered, you can convert these networks into IP address range sets that you use in a Discovery Schedule.

    Note: For advanced discoveries, such as those requiring load balancing or scanning across multiple domains, use Discovery Behaviors.
  7. Validate results.

    Initial discoveries often reveal unexpected results, such as previously unknown devices and processes or failed authentication. Results should also accurately identify known devices and update the CMDB appropriately. Become familiar with the network that is being discovered and the types of data returned for the different types of discoveries. Use the Discovery Log and the ECC Queue to monitor the Discovery process as data is returned from the probes.

    1. To view the actual payload of a probe, click the XML icon in a record in the ECC Queue.
      ECC Queue
    2. Use the Discovery Log form for a quick look at how the probes are doing. To display the Discovery Log, navigate to Discovery > Discovery Log.
      Discovery Log

      The Discovery Log provides the following information:

      Column Information
      Created Displays the timestamp for the probe launched. Click this link to view the record for the probe launched in this list.
      Level Displays the type of data returned by this probe. The possible levels are:
      • Debug
      • Error
      • Information
      • Warning
      ECC queue input Displays the ECC queue name associated with the log message.
      Message Message describing the action taken on the information returned by the probe.
      CI The CI discovered. Click this link to display the record from the CMDB for this CI.
      Source Displays the probe name that generated the log message.
      Device Displays the IP address explored by the probe. Click this link to examine all the log entries for the action taken on this IP address by this Discovery.