Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Understanding Resynchronization of Device Configuration

 

In a network managed by Edge Services Director, three separate repositories about device configuration are maintained:

  • The configuration information on the devices themselves. Each switch and wireless LAN controller maintains its own configuration record.

  • The configuration information maintained by the Junos Space Network Management Platform. When a device is discovered, either by Junos Space or Edge Services Director, Junos Space stores a record of the configuration on that device.

    Edge Services Director uses the configuration record maintained by Junos Space to determine what configuration commands need to be sent to the device when you deploy configuration on the device in Deploy mode.

  • The configuration information maintained by Edge Services Director in Build mode. This information takes the form of the profiles assigned to the device, plus the additional configuration, such as LAG and access point configuration, that you can do under device management.

In Edge Services Director, the configuration state of a device is shown as In Sync when the configuration information in all three repositories match. If there is a conflict between the configuration information in one or more of the repositories, Edge Services Director shows the device configuration state as Out of Sync.

An Out of Sync state is usually the result of out-of-band configuration changes—that is, configuration changes made to a device using a management tool other than Edge Services Director. Examples of such changes include changes made by:

  • Using the device CLI.

  • Using the device Web-based management interface (the J-Web interface or Web View).

  • Using the Junos Space Network Management Platform configuration editor.

  • Using RingMaster software.

  • Restoring or replacing device configuration files.

You cannot deploy configuration on a device when the device configuration state is Out of Sync.

This topic describes how Edge Services Director enables you to resynchronize the device configuration state. It covers:

The Resynchronize Device Configuration Task

Edge Services Director provides a task in Deploy mode that enables you to resynchronize the repositories of configuration information. When an out-of-band configuration change is made, you can use this task to resynchronize both the Junos Space configuration record and the Build mode configuration with the configuration on the device.

How Edge Services Director performs resynchronization depends on the system of record (SOR) mode set for the Junos Space Network Management Platform. There are two possible modes:

  • Network as system of record (NSOR). This is the default mode.

  • Junos Space as system of record (SSOR).

You set the mode in Junos Space under Administration > Applications > Network Management Platform > Modify Application Settings.

How Resynchronization Works in NSOR Mode

In NSOR mode, the network device is considered the system of record for device configuration, which means the configuration maintained by the device takes precedence over the configuration maintained by Junos Space and Edge Services Director. Thus when you perform a resynchronization, the Junos Space configuration record and the Edge Services Director Build mode configuration are updated to match the device configuration.

When an out-of-band change is made on a managed device when Junos Space is in NSOR mode:

  1. Junos Space detects that a configuration change has occurred on the device and informs Edge Services Director about the change.
  2. Both Junos Space and Edge Services Director set the device configuration state to Out of Sync.
  3. Junos Space automatically resynchronizes its configuration record to match the device configuration and sets the device configuration state to In Sync when the synchronization completes.
  4. If the configuration change does not affect configuration that you can perform in Build mode (for example, routing configuration), Edge Services Director also sets the device configuration state to In Sync after the Junos Space resynchronization completes. All three configuration repositories are now in sync.

    If the configuration change affects configuration that you can perform in Build mode, Edge Services Director does not set the device configuration state to In Sync. Instead, it continues to show the device configuration state as Out of Sync because the Build mode configuration does not match the device configuration.

  5. To resolve the Out of Sync state in Edge Services Director, use the Resynchronize Device Configuration task in Deploy mode. Edge Services Director updates the Build mode configuration to match the out-of-band changes.
  6. Edge Services Director sets the device configuration state to In Sync.
Note

Automatic resynchronization, as described in Step 3 above, is a default setting for the Junos Space Network Management Platform. If automatic resynchronization is disabled, you must manually resynchronize the Junos Space configuration with the device configuration. You can do so in two ways:

  • Use the Resynchronize with Network action in Junos Space. The Junos Space configuration is synchronized with the device configuration. However, the Build mode configuration is not synchronized, so the device state in Edge Services Director remains Out of Sync. You must use the Resynchronize Device Configuration task in Deploy mode to resynchronize the Build mode configuration.

  • Use the Resynchronize Device Configuration task in Deploy mode. In this case, Edge Services Director resynchronizes both the Junos Space configuration and the Build mode configuration with the device configuration.

How Resynchronization Works in SSOR Mode

When Junos Space is in SSOR mode, Junos Space is considered the system of record for device configuration. In this mode, when an out-of-band configuration change occurs on a device, you can choose whether to accept the change or to overwrite the change with the configuration maintained by Junos Space.

When an out-of-band change is made on a managed device when Junos Space is in SSOR mode:

  1. Junos Space detects that a configuration change has occurred on the device and informs Edge Services Director about the change.
  2. Junos Space sets the device configuration state as Device Changed, and Edge Services Director sets the device configuration state to Out of Sync.

    Edge Services Director sets the device configuration state to Out of Sync even if the configuration change does not affect configuration you can perform in Build mode. This allows you to resolve the Device Changed configuration state for Junos Space from Edge Services Director.

  3. In Edge Services Director, use the Resynchronize Device Configuration task to accept or reject the out-of-band changes:
    • If you accept the out-of-band changes, both the Junos Space configuration record and the Edge Services Director Build mode configuration are resynchronized to reflect the out-of-band configuration changes.

    • If you reject the out-of-band changes, the configuration on the device is overwritten by the configuration record maintained by Junos Space. The Edge Services Director Build mode configuration remains unchanged.

  4. Both Junos Space and Edge Services Director set the device configuration state to In Sync.

The above process differs somewhat when out-of-band configuration changes are made through the Junos Space configuration editor. In this case:

  1. Junos Space sets the device configuration state as Space Changed after the configuration change is saved.

    At this point, the changes have been made only in the Junos Space configuration record and the changes have not yet been deployed to the device. Edge Services Director shows the device configuration state as In Sync.

    Note

    Because the device configuration state is In Sync in Edge Services Director, you can deploy configuration on the device from Edge Services Director at this point. If you do so, the Edge Services Director changes are deployed on the device, but the Junos Space changes are not. The device state in Junos Space remains Space Changed.

  2. When the changes are deployed to the device from Junos Space, Junos Space changes the device state to In Sync, while Edge Services Director changes the device state to Out of Sync.
  3. In Edge Services Director, use the Resynchronize Device Configuration task to resolve the Out of Sync state. In this case, because the Junos Space configuration record and the device configuration are in sync, you cannot reject the changes. When you resynchronize the device in Edge Services Director, the Build mode configuration is updated to reflect the configuration changes.
  4. Edge Services Director sets the device configuration state to In Sync.

If you use Junos Space instead of Edge Services Director to resolve out-of-band configuration changes in SSOR mode, note the following:

  • If you reject an out-of-band change, the device state becomes In Sync in both Edge Services Director and Junos Space.

  • If you accept an out-of-band change that does not affect the Build mode configuration, the device state becomes In Sync in both Edge Services Director and Junos Space.

  • If you accept an out-of-band change that affects the Build mode configuration, the device state becomes In Sync in Junos Space but remains Out Of Sync in Edge Services Director. You must use the Resynchronize Device Configuration task to resolve the Out of Sync state.

Note

When Junos Space is in SSOR mode, we recommend that you do not make out-of-band changes to the cluster configuration on the secondary seeds and member controllers of a mobility domain, such as disabling the cluster on these devices. Use Edge Services Director to modify the cluster configuration on these devices.

How Edge Services Director Resynchronizes the Build Mode Configuration

A network managed by Edge Services Director has three repositories of information about the configuration of a network device—the configuration stored on the device itself, the device configuration record maintained by Junos Space, and the Build mode configuration maintained by Edge Services Director.

When the configuration contained in all three repositories match, the device configuration state is shown as In Sync in Edge Services Director. When the repositories do not match, the configuration state is shown as Out of Sync. A common cause for this state is out-of-band configuration changes—that is, configuration changes made to a device outside of Edge Services Director.

  • When Junos Space is in network as system of record (NSOR) mode, the device is considered the system of record for configuration. When you resynchronize a device when Junos Space is in NSOR mode, both the Junos Space configuration record and the Edge Services Director Build mode configuration are updated to reflect the device configuration—in other words, the out-of-band configuration changes are incorporated into both the Junos Space and the Edge Services Director configuration repositories.

  • When Junos Space is in Junos Space as system of record (SSOR) mode, you can choose whether accept or reject the out-of-band changes reflected in the device configuration. If you accept the changes, both the Junos Space configuration record and the Edge Services Director Build mode configuration are updated to reflect the device configuration. If you reject the changes, the out-of-band changes are rolled back on the device so that the device configuration matches the Junos Space configuration record and the Edge Services Director Build mode configuration.

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.

For details about resynchronizing devices, see Resynchronizing Managed Devices with the Network.