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Upgrading Junos OS in a Virtual Chassis by Performing a Unified ISSU

You can upgrade the member routers in a two-member Virtual Chassis to a later release by performing a unified in-service software upgrade (unified ISSU). Unified ISSU enables you to upgrade to a new Junos OS software release with minimal traffic disruption and no loss of subscriber sessions.

The unified ISSU procedure upgrades and changes the roles of all Routing Engines in the Virtual Chassis to the new Junos OS software release. In a two-member Virtual Chassis, this includes four Routing Engines: the primary and standby Routing Engines in the Virtual Chassis primary router, and the primary and standby Routing Engines in the Virtual Chassis backup router.

This procedure describes how to upgrade Junos OS in a Virtual Chassis by performing a unified ISSU. For information about upgrading Junos OS in a Virtual Chassis by rebooting the Routing Engines, see Example: Upgrading Junos OS in a Virtual Chassis Configuration for MX Series 5G Universal Routing Platforms by Rebooting the Routing Engines.

Before you begin a unified ISSU in a two-member Virtual Chassis, perform the following tasks:

To perform a unified ISSU in a two-member Virtual Chassis:

  1. Use FTP or a Web browser to download the Junos OS software package from the Juniper Networks Support Web site.

    See Downloading Software.

  2. Open four console windows to access the console ports on each of the four Routing Engines in the Virtual Chassis:

    • Primary Routing Engine in the Virtual Chassis primary router (VC-Pp)

    • Standby Routing Engine in the Virtual Chassis primary router (VC-Ps)

    • Primary Routing Engine in the Virtual Chassis backup router (VC-Bp)

    • Standby Routing Engine in the Virtual Chassis backup router (VC-Bs)

    Opening separate console windows enables you to monitor the progress of the unified ISSU on each of the Routing Engines.

  3. (Optional but recommended) Confirm that the member routers are ready for the unified ISSU process.

    Issue the following commands in each console window:

    Issuing these commands provides the following information:

    • The show virtual-chassis vc-port | match “Configured” command output confirms that all Virtual Chassis port interfaces are properly configured and operational.

    • The show system switchover local command output confirms that the configuration database and kernel database are ready for a unified ISSU.

    • The show system uptime local command output displays the date and time when this Routing Engine was last booted, and how long it has been running. It typically takes from 5 minutes to 15 minutes since the last switchover or system reboot for the Routing Engine to be ready for a unified ISSU.

  4. Verify that all four Routing Engines in the Virtual Chassis are running the same Junos OS software release.

    Issue the show version invoke-on all-routing-engines command with the all-members option to display the hostnames and version information about the software running on all Routing Engines in the Virtual Chassis.

  5. Initiate the unified ISSU process.

    In the console window on the VC-Pp, issue the request system software in-service-upgrade package-name command.

    Note:

    You do not need to specify the reboot option for the request system software in-service-upgrade command because a unified ISSU in a Virtual Chassis always reboots all Routing Engines in the member routers.

    For routers with RE-S-X6-64G Routing Engine, upgrade the guest Junos OS and the Linux VM host OS by issuing the request vmhost software in-service-upgrade package-name command.

  6. Check the console windows for each Routing Engine to monitor the unified ISSU progress and determine when the upgrade is complete.

    The unified ISSU can take between 30 minutes and 90 minutes to complete, depending on the size of your configuration. When the unified ISSU completes, the login prompt appears in the console windows.

For an example of the output for a unified ISSU operation in a Virtual Chassis, see request system software in-service-upgrade and request vmhost software in-service-upgrade.

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