This article explains how to upgrade an EX8200 device without ​nonstop software upgrade ( NSSU), and with minimal traffic loss.
In general, upgrading an EX8200 virtual chassis (VC) through standard procedures requires downtime for the entire virtual chassis. This procedure describes how to reboot XRE and EX8200 routing engines (REs) separately, thereby achieving minimal traffic disruption on the network.

After installing the package on the device, the entire VC is not rebooted; instead all the back-up routing engines will be rebooted first. The traffic will flow through primary REs. Once all backup REs have been upgraded, we will perform a switchover. When the switchover is complete, then we reboot the previous primary REs to complete the upgrade process.

1. Back up your configuration before upgrade. Use the following command to back up the configuration file on a PC or server:

   show configuration |display set |save /var/tmp/Config.txt 

2. ​Deactivate or delete GRES and NSR. Enter configuration mode and disable nonstop active routing.​

   user@switch# deactivate routing-options nonstop-routing

   Deactivate graceful Routing Engine switchover and commit the configuration:

   user@switch# deactivate chassis redundancy graceful-switchover
   user@switch# commit synchronize

3. Enable no split-detection for a two member EX8200VC:

   user@switch# set virtual-chassis no-split-detection

4. Download the software package for EX-XRE200. The software package can be identified on the software download site by confirming that xre200 is listed in the filename as the package name. This package contains the Junos OS image for the external Routing Engines as well as the software packages for the EX8200 switches. Console access to all the routing engines and USB stick is copied with the upgrade code.

5. FTP into the Primary stack and copy the jinstall package to the /var/tmp/ directory. Add the software package on the primary XRE by using the following command:
   
   user@switch# request system software add /var/tmp/ <package-name> ​​
   
   You can check the RE roles by executing the command:  show chassis routing-engin

   Note:  Don’t reboot any of the members now. Follow the steps below.

6. Step by Step procedure:

   1. Upgrading Member1-re1: Take console access to RE0 on member1

      >request system reboot member 1 other-routing-engine

   2. Upgrading Member0-re1: Take console access to RE0 on member0

      >request system reboot member 0 other-routing-engine

   3. Upgrading Backup XRE (Member-9)

      >request system reboot member 9

   4. Do a XRE-Master switchover and make Member-9 as Master:
      
      >request chassis routing-engine master switch

   5. Switch over the primary role for the EX8200’s member-0 re0 to member-0 re1. From shell mode:

      Root% rlogin –Ji member0
      Root% cli
      Root>request chassis routing-engine master switch 

   6. Switch over the primary role for the EX8200’s member-1 re0 to member-1 re1. From shell mode:

      Root% rlogin –Ji member1
      Root% cli             
      Root>request chassis routing-engine master switch

   7. Upgrading Member1-re0: Take console access to RE1 on member1

      > request system reboot member 1 other-routing-engine

   8. Upgrading Member0-re0: Take console access to RE1 on member0

      > request system reboot member 0 other-routing-engine

   9. Upgrading Backup XRE (Member-8):

      request system reboot member 8

   10. Do a XRE-Master switchover and make Member-8 the Master again:

       request chassis routing-engine master switch

       Note: Do a manual switchover to REs on mem0 and mem1

       Root%rlogin –Ji member0
       Root0%cli
       Root>request chassis routing-engine master switch

       Root00%rlogin –Ji member1
       Root0%cli
       Root>request chassis routing-engine master switch

7. After upgrading the devices, activate NSR and GRES.

   user@switch# activate chassis redundancy graceful-switchover
   user@switch# activate routing-options nonstop-routing
   user@switch# commit synchronize 

8. Verify that the members are running the same version of the software:

   user@switch# show version invoke all-members

   
    

2021-03-25: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives.