Symptom

After Disruptive or Non-Disruptive upgrade or disruptive downgrade - the upgrade or downgrade may fail, or the configuration will be corrupted and not complete. Part of configuration can be missing or incorrect. Example VLAN missing, VLAN names garbled, SVI missing and so on. Reload of the device will not recover from this issue nor downgrade to the earlier release. The only ways to recover are ASCII RELOAD or write erase and configure device again. In some cases upgrade will just fail and exit without upgrading.

Conditions

Disruptive or Non-Disruptive Upgrade or Downgrade from 10.4(6)M, and above releases 10.5(1)F, 10.5(2)F, 10.5(3)F Issue could happen on all Nexus 9000 and Nexus 3000 platforms, TOR and modular chassis. New installs are not affected if system boots directly to 10.5(1)F, 10.5(2)F or 10.5(3)F Upgrade from any earlier releases in the 10.4 train (below 10.4(6)) are NOT affected. 10.4(1,2,3,4 or 5) 10.5(x) will work.

Workaround

Recommended solution is to upgrade from 10.4(6)M, 10.4(7)M and beyond in the 10.4 train to 10.5(4)M release or later and skip 10.5(1), 10.5(2), 10.5(3). Possible workarounds: 1. Performing ascii reload resolves the issue and restoration of missing configuration Command: reload ascii \!\\!\\!WARNING\! This command will erase binary configuration in this VDC and reboot the system with ascii configuration. Do you wish to proceed anyway? (y/n) [n] y Configuration need to be verified and restored after reload ascii as part of config might be missing. Please refer to https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/nx-os-software/224704-understand-the-reload-ascii-command.html for more details on using this command. 2. After upgrade/downgrade on affected paths write erase device and recover configuration from the backup !!! below approach can be taken only if upgrade has not been yet done and issue not hit yet !!! If absolutely necessary to have upgrade from 10.4(6) to 10.5(3) below upgrade path can be taken: (this is valid only for disruptive upgrade) 10.4(6) -> 10.5(4) -> 10.5(3)

Further Problem Description