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Migration, Upgrade, and Downgrade Instructions


This section contains information about how to upgrade Junos OS for vSRX using the CLI. Upgrading or downgrading Junos OS can take several hours, depending on the size and configuration of the network.

You also can upgrade to Junos OS Release 20.2R1 for vSRX using J-Web (see J-Web) or the Junos Space Network Management Platform (see Junos Space).

Direct upgrade of vSRX from Junos OS 15.1X49 Releases to Junos OS Releases 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, or 19.2 is supported.

The following limitations apply:

  • Direct upgrade of vSRX from Junos OS 15.1X49 Releases to Junos OS Release 19.3 and higher is not supported. For upgrade between other combinations of Junos OS Releases in vSRX and vSRX 3.0, the general Junos upgrade policy applies.

  • The file system mounted on /var usage must be below 14% of capacity.

    Check this using the following command:

    show system storage | match " /var$" /dev/vtbd1s1f

    Using the request system storage cleanup command might help reach that percentage.

  • The Junos upgrade image must be placed in the directory /var/host-mnt/var/tmp/. Use the request system software add /var/host-mnt/var/tmp/<upgrade_image>

  • We recommended you deploy a new vSRX VM instead of performing a Junos upgrade. That also gives you the option to move from vSRX to the newer and more recommended vSRX 3.0.

  • Ensure to backup valuable items such as configurations, license-keys, certificates, and other files that you would like to keep.


For ESXi deployments, the firmware upgrade from Junos OS Release 15.1X49-Dxx to Junos OS releases 17.4, 18.x, or 19.x is not recommended if there are more than three network adapters on the 15.1X49-Dxx vSRX instance. If there are more than three network adapters and you want to upgrade, then we recommend that you either delete all the additional network adapters and add the network adapters after the upgrade or deploy a new vSRX instance on the targeted OS version.

Upgrading Software Packages

To upgrade the software using the CLI:

  1. Download the Junos OS Release 20.2R1 for vSRX .tgz file from the Juniper Networks website. Note the size of the software image.
  2. Verify that you have enough free disk space on the vSRX instance to upload the new software image.
  3. Optionally, free up more disk space if needed to upload the image.

    If this command does not free up enough disk space, see [SRX] Common and safe files to remove in order to increase available system storage for details on safe files you can manually remove from vSRX to free up disk space.

  4. Use FTP, SCP, or a similar utility to upload the Junos OS Release 20.2R1 for vSRX .tgz file to /var/crash/corefiles/ on the local file system of your vSRX VM. For example:
  5. From operational mode, install the software upgrade package.

    If no errors occur, Junos OS reboots automatically to complete the upgrade process. You have successfully upgraded to Junos OS Release 20.2R1 for vSRX.


    Starting in Junos OS Release 17.4R1, upon completion of the vSRX image upgrade, the original image is removed by default as part of the upgrade process.

  6. Log in and use the show version command to verify the upgrade.

Validating the OVA Image

If you have downloaded a vSRX .ova image and need to validate it, see Validating the vSRX .ova File for VMware.

Note that only .ova (VMware platform) vSRX images can be validated. The .qcow2 vSRX images for use with KVM cannot be validated the same way. File checksums for all software images are, however, available on the download page.