Support Support Downloads Knowledge Base Juniper Support Portal Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[EX] Junos OS upgrade on EX9200 with SF2/RE2 does not go through



Article ID: KB34886 KB Last Updated: 23 Aug 2019Version: 1.0

On EX9200 platforms, when using Switch Fabric 2 (SF2) and Routing Engine 2 (RE2) during an upgrade, customers may notice that the upgrade does not go through and the switch comes back up with the old version.

This article explains that the upgrade process on this platform requires the VMHost software to also be upgraded for it to be successful.


If a regular upgrade is performed on this platform, the switch will come back up after a reboot with the old version (the upgrade will not go through).


On the EX9200 platform, the new RE2s must not only be used along with SF2s but also follow an upgrade process that is slightly different. In this case, the upgrade will require a VMHost upgrade because the architecture is different.

For more information about hardware details for REs and SFs, refer to Host Subsystem in an EX9200 Switch and for the differences in RE and RE2, refer to Routing Engine Module in an EX9200 Switch.


To perform the upgrade on this platform, use the following procedure:

  1. Download the VMHost image by navigating to Downloads and searching for EX92xx (make sure that you use the one listed as VMHost).
  2. Copy the image to /var/tmp/ on the switch.

  3. Run the VMHost upgrade command as follows:
> request vmhost software add /var/tmp/junos-vmhost-install-ex92xx-x86-64-17.1R1.8.tgz
  1. Reboot the device.
> request vmhost reboot

Verify that the upgrade was successful by using the show version command.

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search