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    Understanding How Junos Space Automatically Resynchronizes Managed Devices

    When configuration changes are made on a physical device that Junos Space Network Management Platform manages, Junos Space Network Management Platform reacts differently depending on whether the network itself is the system of record (NSOR) or Junos Space Network Management Platform is the system of record (SSOR).

    In the NSOR case, Junos Space Network Management Platform receives a system log message and automatically resynchronizes with the device. This ensures that the device inventory information in the Junos Space Network Management Platform database matches the current configuration information on the device.

    In the SSOR case, the Junos Space Network Management Platform receives a system log message from device after the device change is committed. Managed status for that device changes to out-of-sync, but no resynchronization occurs. The Junos Space Network Management Platform administrator has the option of resetting the network device’s configuration to the Junos Space Network Management Platform database values or not doing so.

    This topic covers:

    Network as System of Record

    After Junos Space Network Management Platform discovers and imports a device, if the network is the system of record, Junos Space Network Management Platform enables the auto-resynchronization feature on the physical device by initiating a commit operation.

    After auto-resynchronization is enabled, any configuration changes made on the physical device, including out-of-band CLI commits and change-request updates, automatically trigger resynchronization on the device. Figure 1 shows how a commit operation on the device triggers resynchronization.

    Figure 1: Resynchronization Process

    Resynchronization Process

    When a commit operation is performed on a managed device under NSOR, Junos Space Network Management Platform, by default, schedules a resynchronization job to run 20 seconds after the commit operation is received. However, if Junos Space Network Management Platform receives another commit notification within 20 seconds of the previous commit notification, no additional resynchronization jobs are scheduled because Junos Space Network Management Platform resynchronizes both commit operations in one job. This damping feature of automatic resynchronization provides a window of time during which multiple commit operations can be executed on the device, but only one or a few resynchronization jobs are required to resynchronize the Junos Space Network Management Platform database after multiple configuration changes are executed on the device.

    You can change the default value of 20 seconds to any other duration by specifying the value in seconds in the Administration > Applications > Network Management Platform > Modify Application Settings > Device > Max auto resync waiting time secs field. For example, if you set the value of this field to 120 seconds, then Junos Space Network Management Platform automatically schedules a resynchronization job to run 120 seconds after the first commit operation is received. If Junos Space Network Management Platform receives any other commit notification within these 120 seconds, it resynchronizes both commit operations in one job.

    When Junos Space Network Management Platform receives the device commit notification, the device status is “Out of Sync”. When the resynchronization job begins on the device, the Managed Status for the device displays “Synchronizing” and then “In Sync” after the resynchronization job has completed, unless a pending device commit operation causes the device to display “Out of Sync” while it was synchronizing.

    When a resynchronization job is scheduled to run but another resynchronization job on the same device is in progress, Junos Space Network Management Platform delays the scheduled resynchronization job. The time delay is determined by the damper interval that you can set from the application workspace. By default, the time delay is 20 seconds. The scheduled job is delayed as long as the other resynchronization job to the same device is in progress. When the currently running job finishes, the scheduled resynchronization job starts.

    You can disable the auto-resynchronization feature in the Application workspace. When auto-resynchronization is turned off, the server continues to receive notifications and will go into the out-of-sync state; however, the auto-resynchronization does not run on the device. To resynchronize a device when the auto-resynchronization feature is disabled, you can use the resynchronization feature to manually resynchronize the device.

    For information about setting the damper interval to change the resynchronization time delay and information about disabling the auto-resynchronization feature, see Modifying Junos Space Application Settings.

    Junos Space as System of Record

    If Junos Space Network Management Platform is the system of record, the automatic resynchronization described above does not occur. When Junos Space Network Management Platform receive the device commit notification, device status becomes Out of Sync and remains so unless you push the system-of-record configuration from the Junos Space Network Management Platform database down to the device.

    Published: 2014-08-19