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    Rolling Back a Software Upgrade

    Use this procedure to roll back a software upgrade to the release from which you upgraded. This procedure covers rolling back the software upgrade on the CMMs and on all of the traffic modules. Both the software and the configuration are rolled back.

    Caution: This procedure is service affecting.

    Note: You can only roll back software if you have made no hardware changes and made no hardware replacements in the system. Once you make a hardware change, you cannot roll back software.

    Prerequisites:

    • In releases lower than release 4.3, you must have superuser privileges to roll back a software upgrade. In releases 4.3 and higher, you can roll back a software upgrade with the provisioning privilege.
    1. Log in to the CLI using the shared management IP address.
    2. In order to roll back the upgrade, the upgrade itself must have been successful.

      Use the show system upgrade command to verify that the upgrade was successful.

      For example (partial output only):

      bti7800# show system upgrade
      Current Status      : commit-success  
      Software Rollback : Rollback eligibility has not been evaluated 

      If the Current Status is commit-success, then you can attempt to roll back the upgrade.

      The show system upgrade output contains a message describing the Software Rollback status. Whether a rollback can be performed successfully or not depends on a number of internal conditions. The message Software Rollback : Rollback eligibility has not been evaluated means that those conditions have not been checked yet. Those conditions are only checked after you initiate the rollback command. Once you initiate the rollback command, this message will change to reflect the rollback progress or display an error message if the rollback attempt has failed.

    3. Perform the software rollback.

      Use the system upgrade rollback command to perform the rollback. For example:

      bti7800# system upgrade rollback
      CAUTION: Software rollback may affect traffic and configuration, 
      Would you like to proceed? [no,yes] yes bti7800# 

      In response to the rollback command, the system performs cursory sanity checks to see if the rollback request is permitted to proceed. If any of these checks fails, the system returns an error message immediately, and the command fails. If the rollback request is permitted to proceed, then the CLI prompt is returned.

      Note: The request can still fail at a later stage. If this occurs, the reason for failure will be provided in the output of the show system upgrade command.

    4. Check on the status of the rollback.

      You can check on the status of the rollback by issuing the show system upgrade command periodically.

      For example (partial output only):

      bti7800# show system upgrade
      Current Status      : Rollback in progress 

      Note: During rollback, you will lose management connectivity. Wait several minutes before connecting to the shared management IP address again. Once you log back in, continue to check on the status of the rollback.

      bti7800# show system upgrade
      Current Status      : Rollback succeeded -- previous application and configuration restored 

      Proceed to the next step only after the rollback has succeeded.

    5. Roll back the CMM firmware if needed.

      If you upgraded to new CMM firmware after you upgraded to the new software, you will need to roll back the firmware to the previous version. To do this, use the same procedure as you used to upgrade the CMM firmware. See Upgrading the CMM Firmware.

    6. Roll back firmware on the traffic modules if needed.

      The system automatically rolls back traffic module firmware if the firmware was upgraded. In some older releases, this rollback is not automatic, and you will need to explicitly roll back the traffic module firmware to the previous version. Use the system upgrade firmware ipmc command to roll back the traffic module firmware if the firmware does not roll back automatically. You will see the Firmware Upgrade Required (firmUpgrdReqd) alarm in this case.

    7. Cold reboot all modules in the system.

      If you are rolling back to release 2.0 or higher, the system automatically performs a cold reload of all modules as part of 3, and you can skip to the next step. Otherwise, cold reboot all modules as follows:

      • If you are rolling back to a release that supports the system reload all cold command, then issue that command to perform a cold reload of all modules.
      • If you are rolling back to a release that does not support the system reload all cold command, then use the system reload cold command on each module individually.
    8. After all modules have rebooted successfully, check over the system.
      1. Use the show system version command to verify that all modules have rolled back to the previous version of software.
      2. Use the show equipment command to verify that all modules are up and running.
      3. Use the show alarms command to verify that no unexpected alarms have been raised due to the rollback.

    Release History Table

    Release
    Description
    In releases 4.3 and higher, you can roll back a software upgrade with the provisioning privilege.

    Modified: 2017-10-30