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[SRX] What is SRX Virtual Chassis and how does it impact device management?



Article ID: KB18228 KB Last Updated: 24 Nov 2020Version: 8.0

SRX Virtual Chassis is used when the standby SRX cluster member has no route to the management system. This was introduced for use by NSM2010.2 and later. Junos Space also supports this feature. In this article, you learn more about this feature.



When a device is located at the edge of a remote site, the standby SRX cluster member usually does not have an available route to reach the management system.

Therefore, it is preferable to configure a route for both cluster member Routing Engines to reach the management system whenever possible.

SRX Virtual Chassis (VC) allows for in-band management of an SRX cluster by using Netconf. This enables the management system to view the entire cluster as a single unit. Some commands will now return data for both cluster members instead of only the device that the command is run on.

In order to enable SRX Virtual Chassis on the device, the following command must be added to the configuration.

root@srx# set chassis cluster network-management cluster-master

This setting needs to be added to the device before adding the device to the management system. If the setting is added after, delete and re-add the device from the management system.

Note: This is a hidden command in many Junos OS versions. You must type it completely and not depend on auto-complete. This is supported for all SRX platforms from Junos OS Release 10.4 and later (SRX-branch from Junos OS Release 10.1R2).

Example Connection of Cluster to Management System (NSM)

For NSM: In order to add an SRX VC in unreachable mode, make sure to select the check box for "Virtual Chassis" in the window where you need to specify the device platform, OS name and other details. In reachable mode, NSM will detect the device as a VC and add it.

Note: In case you want to revert the configuration and manage it via fxp0 interface (as a normal cluster), refer to KB26414 - NSM/Junos Space fails to recognize SRX as a cluster/standalone device type unless Virtual Chassis flag is removed.


Modification History:

2020-07-22: Archived

2020-11-24: Article modified to apply to any management system, not only NSM


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