Upgrading Software Using Nonstop Software Upgrade on EX Series Virtual Chassis and Mixed Virtual Chassis (CLI Procedure)

Before you begin software installation using NSSU:

• Ensure that the Virtual Chassis is configured correctly to support NSSU. Verify that:

  • The Virtual Chassis members are connected in a ring topology. A ring topology prevents the Virtual Chassis from splitting during an NSSU.

  • The Virtual Chassis primary and backup are adjacent to each other in the ring topology. Adjacency permits the primary and backup to always be in sync, even when the switches in linecard roles are rebooting.

  • The Virtual Chassis is preprovisioned so that the linecard role has been explicitly assigned to member switches acting in the linecard role. During an NSSU, the Virtual Chassis members must maintain their roles—the primary and backup must maintain their primary and backup roles (although primary role will change), and the other member switches must maintain their linecard roles.

    For information on configuring a preprovisioned Virtual Chassis, see Configuring an EX3300 Virtual Chassis (CLI Procedure), Configuring an EX4200, EX4500, or EX4550 Virtual Chassis (CLI Procedure), Configuring an EX2300, EX3400, or EX4300 Virtual Chassis, and Configuring an EX8200 Virtual Chassis (CLI Procedure).

  • A two-member Virtual Chassis has no-split-detection configured so that the Virtual Chassis does not split when an NSSU upgrades a member.

• Verify that the members are running the same version of the software:

  If the Virtual Chassis members are not running the same version of the software, use the request system software add command to upgrade the software on the inconsistent members.

• Ensure that nonstop active routing (NSR) and graceful Routing Engine switchover (GRES) are enabled. To verify that they are enabled, you need to check only the state of nonstop active routing—if nonstop active routing is enabled, then graceful Routing Engine switchover is enabled.

  To verify that nonstop active routing is enabled:

  If nonstop active routing is not enabled (Stateful Replication is Disabled), see Configuring Nonstop Active Routing on Switches for information on how to enable it.

• For the EX4300 Virtual Chassis, you should enable the vcp-no-hold-time statement at the [edit virtual-chassis] hierarchy level before performing a software upgrade using NSSU. If you do not enable the vcp-no-hold-time statement, the Virtual Chassis may split during the upgrade. A split Virtual Chassis can cause disruptions to your network, and you may have to manually reconfigure your Virtual Chassis after the NSSU if the split and merge feature was disabled. For more information about a split Virtual Chassis, see Understanding Split and Merge in a Virtual Chassis.

• (Optional) Enable nonstop bridging (NSB). Enabling NSB ensures that all NSB-supported Layer 2 protocols operate seamlessly during the Routing Engine switchover that is part of the NSSU.

• (Optional) Back up the system software—Junos OS, the active configuration, and log files—on each member to an external storage device with the request system snapshot command.

To upgrade all members using NSSU:

1. Download the software package. If you are upgrading the software running on a mixed Virtual Chassis, download the software packages for both switch types.

2. Copy the software package or packages to the Virtual Chassis. We recommend that you copy the file to the /var/tmp directory on the primary.

3. Log in to the Virtual Chassis using the console connection or the virtual management Ethernet (VME) interface. Using a console connection allows you to monitor the progress of the primary switch reboot.

4. Start the NSSU:

   • On an EX3300 Virtual Chassis, EX3400 Virtual Chassis, EX4200 Virtual Chassis, EX4300 Virtual Chassis, EX4500 Virtual Chassis, or EX4550 Virtual Chassis, enter:

     where package-name.tgz is, for example, jinstall-ex4200-12.1R2.5-domestic-signed.tgz.

   • On a mixed Virtual Chassis, enter:

     where [/var/tmp/package-name.tgz /var/tmp/package-name.tgz] specifies the EX4200 and EX4500 software packages.

   The switch displays status messages similar to the following messages as the upgrade executes:

5. Log in after the reboot of the original primary switch completes. To verify that the software on all Routing Engines in the Virtual Chassis members has been upgraded, enter the following command:

6. To ensure that the resilient dual-root partitions feature operates correctly, copy the new Junos OS image into the alternate root partitions of all members:

   Resilient dual-root partitions allow the switch to boot transparently from the alternate root partition if the system fails to boot from the primary root partition.