Symptom
ISSU upgrade from 17.6.5 to 17.9.5 will fail if command line exit-address-family is present in the configuration. It will show the following errors:
%IOSXEBOOT-4-MCL_ERR: (rp/0): Aborting ISSU Operation due to MCL Errors. Please wait for the abort operation to complete before initiating the config change or ISSU operation
Finished wait for Standby to reach terminal redundancy state
ERROR: MCL-Terminating the current ISSU Operation. ISSU Abort operation is initiated
ERROR: Once ISSU abort is done please check full list of mismatched commands via:
ERROR: show redundancy config-sync failures historic mcl
The given command will show:
Mismatched Command List
-----------------------
! "router"
- exit-address-family
! "router"
Conditions
This is a platform-independent, day-1 issue.
ISSU Upgrade when "scope" mode is configured for VRF, followed by ipv4/ipv6 configurations in global router bgp mode. Example config:
router bgp 10
bgp log-neighbor-changes
!
scope vrf test
neighbor 1.1.1.1 remote-as 1
!
!
address-family ipv4
exit-address-family
Workaround
Option 1: Configure "scope global" under router bgp mode.
Option 2: Perform a regular upgrade instead of ISSU
Option 3: Avoid scope mode for VRF configurations
Option 4: Remove the whole address-family statement outside of scope mode
Further Problem Description
This also applies to address-family ipv6
