Understanding Resynchronization of Device Configuration
In a network managed by Network 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 Network Director, Junos Space stores a record of
the configuration on that device.
Network 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 Network 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 Network 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, Network 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 Network 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.
Note: You cannot use the Junos Space configuration editor to configure wireless LAN controllers.
- 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 Network Director enables you to resynchronize the device configuration state. It covers:
The Resynchronize Device Configuration Task
Network 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 Network 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 Network Director. Thus when you perform a resynchronization, the Junos Space configuration record and the Network 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:
- Junos Space detects that a configuration change has occurred on the device and informs Network Director about the change.
- Both Junos Space and Network Director set the device configuration state to Out of Sync.
- 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.
- If the configuration change does not affect configuration
that you can perform in Build mode (for example, routing configuration),
Network 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, Network 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.
- To resolve the Out of Sync state in Network Director, use the Resynchronize Device Configuration task in Deploy mode. Network Director updates the Build mode configuration to match the out-of-band changes.
- Network 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:
|
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:
- Junos Space detects that a configuration change has occurred on the device and informs Network Director about the change.
- Junos Space sets the device configuration state as Device
Changed, and Network Director sets the device configuration state
to Out of Sync.
Network 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 Network Director.
- In Network 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 Network 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 Network Director Build mode configuration remains unchanged.
- Both Junos Space and Network 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:
- 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. Network Director shows the device configuration state as In Sync.
Note: Because the device configuration state is In Sync in Network Director, you can deploy configuration on the device from Network Director at this point. If you do so, the Network Director changes are deployed on the device, but the Junos Space changes are not. The device state in Junos Space remains Space Changed.
- When the changes are deployed to the device from Junos Space, Junos Space changes the device state to In Sync, while Network Director changes the device state to Out of Sync.
- In Network 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 Network Director, the Build mode configuration is updated to reflect the configuration changes.
- Network Director sets the device configuration state to In Sync.
If you use Junos Space instead of Network 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 Network 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 Network 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 Network 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 Network Director to modify the cluster configuration on these devices. |
How Network Director Resynchronizes the Build Mode Configuration
When you use the Resynchronize Device Configuration task to resynchronize the Build mode configuration to the device configuration, Network Director launches a resynchronization job. This job deletes all profile assignments configured for the device. The profiles themselves are not deleted—just the assignments of the profiles to the device are deleted. It then reimports the device configuration, as if the device were a newly discovered device. It reassigns existing profiles and creates new profiles as necessary. Profiles that were originally assigned to the device will be reassigned to the device if the profiles were unaffected by the out-of-band changes. All profiles assigned to the device are in a deployed state at the end of the process. Any profile that is not reassigned to the device and is not assigned to any other device will be in a unassigned state.
