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Upgrade Junos OS Evolved Using a PXE Boot Server

Learn how to upgrade Junos OS Evolved using a Preboot Execution Environment (PXE) boot server. This topic covers how to configure the TFTP server and initiate a network-based boot from the command-line prompt to complete the software installation.

Overview

This topic explains how to upgrade Junos OS Evolved by using a Preboot Execution Environment (PXE) boot server.

A PXE boot prepares a client/server environment to boot devices by using a network interface that is independent of available data storage devices or installed operating systems. The image of the operating system is stored on a Trivial File Transfer Protocol (TFTP) server. You can have a separate PXE boot server for each image.

Before You Begin

Ensure that the following prerequisites are met before you attempt a PXE boot:

  • A Linux-based TFTP server is configured and accessible on the network.
  • The TFTP server root directory is /var/lib/tftpboot/.
  • The appropriate Junos OS Evolved installation image, srxsme2-arm is downloaded.
  • Functional network connectivity exists between the device and the TFTP server.
  • The 7z (p7zip) utility is installed on the TFTP server.
  • Console access to the device is available.

Initiate PXE Boot from the Command-Line Prompt

Use this method when you need full control over the PXE boot configuration through the command line. This method extends the basic TFTP server configuration with a PXE boot menu and additional boot file entries, enabling network-based booting from a standard operating system prompt.

Configure the TFTP Server

Perform the following steps on the TFTP server:

  1. Copy the Junos OS Evolved installation image to the TFTP boot directory and extract the ISO image.
  2. Copy the Extensible Firmware Interface (EFI) boot binary to the TFTP root directory.
  3. Create a symbolic link to the EFI boot binary.
  4. Create the secure boot directory under the TFTP root.
  5. Copy the secure boot files to the secure boot directory.
  6. Copy the GRUB startup configuration file to the TFTP root directory.
  7. Create the PXE boot configuration directory under the TFTP root.

  8. Create the default PXE boot menu configuration file under the pxelinux.cfg directory.

    The default file defines the boot label and timeout for the PXE boot process. Create the file with the following contents:

  9. Create a symbolic link for the boot file under the TFTP root directory.

Initiate PXE Boot from the Command-Line Prompt

After you configure the TFTP server, reboot the device. The device automatically detects the PXE boot server on the network and begins the installation process using the configured boot menu.

  • Reboot the device from the command-line prompt.
  • The device broadcasts a DHCP/BOOTP request on the network. The PXE boot server responds and the device downloads the boot file via TFTP.
  • The device loads the Junos OS Evolved installation image and performs the upgrade automatically. After installation completes, the device reboots into the newly installed Junos OS Evolved release.

After the installation is complete, verify the software version by entering the show version command from the Junos OS Evolved operational mode CLI. Juniper Networks does not support using the request system software rollback command to revert to the previously installed software version after a PXE boot installation.

Platform-Specific PXE Boot Behavior

Use Feature Explorer to confirm platform and release support for specific features.

Use the following table to review platform-specific behaviors for your platform:

Platform

Difference

SRX Series

  • SRX400, SRX440, and SRX440-2AC support PXE Boot on Junos OS Evolved.