Discovery Poll

Description

A discovery poll is a sequence of actions that Netreo takes to discover basic information about a managed device and then apply various Netreo settings to that device to ensure that the device is being monitored properly and that the appropriate data is being collected from it.

Typically, a discovery poll is required anytime something significant about the device is changed, either within Netreo or on the device itself.

A discovery poll may be executed at any time on a single device or on a group of devices, as necessary.

How Discovery Polls Work

What Happens

When Netreo executes a discovery poll on a managed device it retrieves the following basic information:

• What type of device it is.
• The name of the device.
• Parent/child relationship with connected devices.
• The list of interfaces and instances on the device.
• The list of available metrics that can be collected (SNMP devices only).
• The list of connected subnets (router/switch only).
• Dynamic device attributes.

Some of this information is used to populate the Device Dashboard of the device and some of it is used during the execution of auto-configuration rules.

The actual sequence of actions that take place during a discovery poll for a device is as follows:

1. The information above is retrieved from the device.
2. The device is run through the auto-configuration rules and any applicable changes made.
3. Any device templates for which the device qualifies have their settings applied to the device.
4. The device is queried for SNMP performance metrics and other miscellaneous information (which may change as a result of the auto-configuration and device template application process).
5. The device is run through the auto-configuration rules a second time and any applicable changes made (due to potential changes from device templates).
6. Any device templates for which the device qualifies have their settings applied to the device.
7. If any device settings have changed due to auto-configuration, the whole discovery poll process is run again.

The Poll Device setting on the Main tab of the administrative view of the Device Dashboard must be set to Active for changes to a managed device to trigger a discovery poll.

When Is It Required

Many changes made to a managed device within Netreo will automatically trigger a discovery poll, while other changes require a discovery poll to be initiated manually by a user (typically an administrator who made the change).

For example, changing pretty much any of the settings on the Main tab of the administrative view of a device's Device Dashboard will require a discovery poll. In this case, most changes made there will automatically trigger a discovery poll for that single device when the Apply Changes button is selected.

Changes made to individual device templates applied to a device, or changing, adding, or removing device templates from a device, also require a discovery poll for the changes to take effect. However, in this case, the discovery poll must be manually initiated by the user, and must include all of the devices affected.

There are several events that automatically trigger a discovery poll:

• When a device is first discovered by Netreo.
• The regularly scheduled auto-discovery process.
• When changing configuration settings in the administrative view of the Device Dashboard for a device.
• A device reboot (if uptime is less than 5-minutes).
• When making a call to Netreo's New Device API for a device that already exists as a managed device in Netreo.
• Occasionally, during a software upgrade.

A discovery poll may also be manually executed the following ways:

• Through a manual repoll of a single device (Debugging Tools > Run Discovery Poll from the Main tab of the administrative view of the device's Device Dashboard).
• Through a manual discovery poll for single or multiple devices on the Repoll Devices page (Administration > Change Devices > Rediscover Devices in the main menu, or Rediscover devices and apply templates button from the Device Templates Administration page).

In either case, when a discovery poll is scheduled for a device or devices, Netreo will post a message near the top of the page. If you don't see this message, no discovery poll has been scheduled. So, if you've made a change to a managed device, and a discovery poll did not automatically get scheduled, you may wish to manually initiate one.