How to identify the HOST-OS version running on QFX5100 ?

Procedure to verify the Host-OS version running on QFX5100 Device.

Host-OS version verification may be required at the time of QFX5100 deployment/installation and it may also be required while performing software upgrades. Additionally, Host-OS version verification is also required during troubleshooting sessions.

In QFX5100, Junos is no longer the main operating system on the hardware but is instead running as a guest virtual machine on the linux based host operating system. The QFX5100 natively boots into Host-OS and uses KVM as a hypervisor to create virtual machines. Junos, the network operating system, runs inside of a VM. As a result of which from time to time we may need to verify the Host-OS running on the QFX5100 device along with Junos OS.

Procedure 1 : To Verify the Host-OS Version on a QFX5100 Device use the “show version” command.

Procedure 2 : We can also verify the Host-OS version running on QFX5100 system by logging into to the Host-OS Shell using the “request app-engine host-shell” from Junos CLI

Note : Ensure that you are logged in to QFX5100 as a root user before running “request app-engine host-shell” command.

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James Palmer


  • After upgrading my 5100, the host software is still showing as the old version while the other ones show the updated version. Any reason why?

    • On QFX10000 and QFX5200 switches, when you perform a software upgrade, the Host OS is automatically upgraded. However, on QFX5100 and EX4600 switches, the Host OS is not upgraded automatically, so you must use the force-host option.

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