Product Documentation

Understanding the Discovery Process

May 27, 2015

Command Center initiates the discovery process when you add the devices to the map. Command Center discovers devices based on the user credentials and/or the host names and IP addresses that you provide when adding a map or device.

After you initiate the discovery process, the device goes through a series of steps. Each step and its status in the discovery process are visible in Command Center. To view the discovery status, see Viewing the Discovery Status of Devices.

The Command Center discovery process involves the following steps:

  1. SNMP ping: The Command Center server sends a Simple Network Management Protocol (SNMP) GET request to a Citrix system-specific object identifier (OID) (for example, 1.3.6.1.4.1.5951.1.1). If the server successfully pings the device, it sets the status of step 2 to SUCCESS and proceeds to step 3. If the GET request fails, the device is not a Citrix device, or it is a Citrix device but SNMP is disabled on it. In either fail case, the Command Center server proceeds to step 2.
  2. Find Citrix device: The Command Center server attempts to open an SSH session to the device based on the user credentials configured when adding a map. If the SSH session fails, the device is discarded as a non-Citrix device. If the SSH session succeeds, the server issues a CLI command to check whether the device is a Citrix device. A positive result moves the device to the next step. Otherwise, Command Center discards the device as a non-Citrix device. To check the cause of failure of this step, on the Citrix Network tab, click the device, and click Status. You can also view the cause of failure on the Device Status page.
  3. Enable SNMP: On the discovered Citrix device, Command Center executes a command to configure an SNMP community based on the details entered when configuring the map or when adding a device. This step may fail for various reasons, such as network issues or if another SNMP manager is already configured on the device.
  4. Add trap destination: Devices communicate with Command Center by sending trap notifications. The Command Center server adds its IP address to the list of trap destinations on the discovered device. This allows Command Center to receive all events/traps generated on the Citrix device. However, this step may fail if the number of trap destinations exceeds the maximum limit of trap destinations on the Citrix device. The limit on Citrix NetScaler devices is 10. If an error occurs you must take corrective measures before you initiate rediscovery of this device.
    Note: If Command Center is behind a Network Address Translation (NAT) device, the trap destination configured on the server is its internal IP, and the events and traps generated by the Citrix device do not reach the Command Center server. To set the trap destination in this case, you must configure it from the Administration tab. For more information, see “Setting Up an SNMP Trap Destination” in the Citrix Command Center Administrator’s Guide.
  5. Collect inventory: The Command Center server collects the basic system information for the discovered devices using SNMP. You can view this information on the Device Properties page. For more information, see “Viewing Device Properties” in the Citrix Command Center Online Help. This step may fail if the SNMP manager configured on the Citrix device is not that of the server. It may also fail because of network issues or because the SNMP ports are not configured properly on the firewall. If an error occurs you must take corrective measures, and then initiate rediscovery of the device.
  6. Download files: The Command Center server initiates a Secure File Transfer Protocol (SFTP) session based on the user credentials defined while configuring the map. Then, it downloads the configuration and license files of the device. For CloudBridge devices, it downloads only the configuration files. The Command Center server stores these files in the database. This step may fail because of the following reasons:
    • Incorrectly specified user credentials
    • Incorrectly configured SFTP ports in the firewall
    • Network issues
    To check the cause of failure, on the Citrix Network tab, click the device, and click Status. You can also view the cause of failure on the Device Status page. If an error occurs, you must take corrective measures, and then initiate rediscovery of this device.
Note: If the discovery process fails, the failed step is marked as FAILED. Any subsequent steps are marked as N/A.

Upon successful discovery, the devices appear on the corresponding maps as icons with their IP addresses or device names. If the server is unable to successfully discover the devices, it marks the devices as inaccessible, generates an event, and groups the devices under the Inaccessible Systems node.