Symptom

One-shot ISSU software between NPE IOS-XE images will fail on Catalyst 9500 series switches during stage 1 showing the following errors. Issue will also occur while doing a 3-step ISSU upgrade during the activation phase. Switch# install add file flash:cat9k_iosxe_npe.16.12.04.SPA.bin active issu commit STAGE 1: Installing software on Standby =================================================== --- Starting install_remote --- --- Starting ISSU compatibility verification --- FAILED: ISSU compatibility check failed [2] Finished install_remote on switch 2 install_remote: Passed on []. Failed on [2] Finished install_remote FAILED: Stage 1 - remote installation failed FAILED: install_add_activate_commit exit(1) Wed Feb 24 03:54:03 MSK 2021 Switch# Feb 24 03:54:06.191 MSK: %INSTALL-3-OPERATION_ERROR_MESSAGE: Switch 1 R0/0: install_engine: Failed to install_add_activate_commit package sxe_npe.16.12.04.SPA.bin, Error: FAILED: ISSU compatibility check failed Feb 24 03:54:06.208 MSK: %INSTALL-3-OPERATION_ERROR_MESSAGE: Switch 1 R0/0: install_engine: Failed to install_add_activate_commit package sxe_npe.16.12.04.SPA.bin, Error: [2]: FAILED: install_remote failed in switch 2 Feb 24 03:54:06.223 MSK: %INSTALL-5-INSTALL_COMPLETED_INFO: Switch 1 R0/0: install_engine: Completed install one-shot ISSU sxe_npe.16.12.04.SPA.bin

Conditions

- Perform ISSU software upgrade between any NPE images from IOS-XE 16.12.1 to IOS-XE 16.12.5 on Catalyst 9000 series switches supporting the StackWise-Virtual feature. The issue is not seen if the ISSU software upgrade is performed between regular non-NPE images. Issue is specific to 16.12 releases. - Note: ISSU between LDPE and NPE software images is not supported. Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst_standalones/b-in-service-software-upgrade-issu.html

Workaround

This will be fixed in IOS-XE 16.12.6. Once that release become available, the ISSU software upgrade between NPE images from 16.12.6 to any other later release on that train should work properly.

Further Problem Description