Description

This article explains how to reinstall or recover a system with a USB Emergency Boot Device on VMHOST platforms.

Solution

Refer to the following link to prepare a bootable USB memory stick (how to create):

Installation images are available for each platform:

  • junos-vmhost-install-usb-mx-x86-64-18.4R1.8.img

  • junos-vmhost-install-usb-ptx-x86-64-18.4R1.8.img

  • junos-vmhost-install-usb-qfx-x86-64-18.4R1.8.img

  • junos-vmhost-install-usb-srx-x86-64-22.4R1.10.img

If you are unsure which image to use, refer to KB33703 - Supported Junos Images on VMhost (Nextgen Routing Engine, x86 CPU based hardware) [juniper.net].

Set the bootable USB device to the target device, and then restart the device. Unlike non-VMHOST Routing Engines, a VMHOST system cannot be restarted with the request system reboot command in Junos CLI. The Junos OS system runs over a host Linux system upon the VMHOST platform; therefore, it requires the entire system to restart so that the USB boot loader can start.

To restart the host system, you have the following options:

  1. Issue the request vmhost reboot usb command. This command was introduced in each platform, but the corresponding first version is different. Refer to the technical document on  request vmhost reboot. 

  2. Log in to the host Linux system and issue the reboot command.

Example for MX Series platform with RE-MX-X6(RE-S-2X00x6):

lab@mx240-NG-RE-re0> start shell user root 
Password:
root@mx240-NG-RE-re0:/var/home/lab # rsh -JU __juniper_private5__ 192.168.1.2
root@mx240-NG-RE-re0:/var/home/lab # reboot

                                             or

root@mx240-NG-RE-re0:/var/home/lab # shutdown -r now

  1. Power cycle manually.

During restart, some screens will look similar to the following. Select the appropriate line. (Some platforms may display a slightly different screen or description.)

  1. Select USB as the boot device:

  1. Select Install Juniper Linux:

Modification History

2023-03-24: Added SRX5k as applicable platform. SRX5k RE3 (SRX5K-RE3-128G) is a VMHOST platform.

2020-09-17: Corrected the option string in 'request vmhost reboot usb'.