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[EX] How to upgrade the software version for an EX-Series Switch Virtual Chassis environment



Article ID: KB10840 KB Last Updated: 17 Mar 2021Version: 8.0

The EX-Series Switch Virtual Chassis (VC) software can be upgraded for the entire VC or you can upgrade one individual member of the VC.

This article explains how this is done.



EX-Series Switches in a virtual chassis environment can be upgraded individually or all members can be upgraded at once from the Primary EX (Routing Engine (RE)). This procedure defines how to use either method.

  • To upgrade all members, use the command request system software add <file> reboot on the primary chassis (RE). This command will upload the software file to all Virtual Chassis (VC) members and reboot them when the upload is complete.

  • To upgrade one member of a VC, use the command request system software  add <file> member <member_number> on the primary chassis (RE). This will upload the file to the requested member chassis only.

To find the member ID, use the command:

user@switch> show virtual-chassis status
Virtual Chassis ID: 001f.1230.478                                        Mastership              Neighbor     List
Member ID       Status    Serial No        Model            priority       Role      ID     Interface
0 (FPC 0)       Prsnt     BN0000000001     ex4200-24p         255          Master*     1      vcp-0     2       vcp-1
1 (FPC 1)       Prsnt     BQ0000000002     ex4200-48p         254          Backup      2      vcp-0     0       vcp-1
2 (FPC 2)       Prsnt     BM0000000003     ex4200-24t         128          Linecard    0      vcp-0     1       vcp-1 

Verify that the new software version is installed properly:

user> show version
Hostname: switch
Model: ex4200-24t
Junos: 15.1R7.9
JUNOS EX  Software Suite [15.1R7.9]
JUNOS FIPS mode utilities [15.1R7.9]
JUNOS Online Documentation [15.1R7.9]
JUNOS EX 4200 Software Suite [15.1R7.9]
JUNOS Web Management Platform Package [15.1R7.9]

​Outage Impact

  • For complete VC upgrade, the outage is bigger because all the VC linecards will reboot, including the primary RE and the backup RE so that new code will be in effect.

  • For a single FPC upgrade, the outage is minimal because the impact will be to traffic only on that specific FPC.  

*** System shutdown message from root@ ***
System going down in 30 seconds
*** FINAL System shutdown message from root@lab1 ***

System going down IMMEDIATELY

Waiting (max 60 seconds) for system process `vnlru' to stop...done
Waiting (max 60 seconds) for system process `vnlru_mem' to stop...done
Waiting (max 60 seconds) for system process `bufdaemon' to stop...done
Waiting (max 60 seconds) for system process `syncer' to stop...
Syncing disks, vnodes remaining...2 2 2 2 1 1 1 1 0 1 1 1 1 0 0 0 0 done

syncing disks... All buffers synced.
Uptime: 4m16s
recorded reboot as normal shutdown

​For a single FPC to recover it may take approximately 2 minutes (keeping in mind that it is not just reboot but upgrade as well).

For the complete VC to recover with upgrade, it will take longer depending on the number of FPCs in the VC.

All these activities must be performed during a planned maintenance window.


Modification History:

2021-03-17: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives
​2020-08-25: Outputs updated
2019-03-14: added Outage impact information

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