Description

When loading the SPC3 card, if you configure unified-services ( Next Gen Services /  USF mode) on the primary Routing Engine (RE) and do not configure the same on the backup RE, a ksycnd coredump occurs along with a kernel live coredump during commit of the graceful Routing Engine switchover (GRES)/nonstop active routing (NSR) configuration.

This article explains how to avoid this problem.

Symptoms

Coredump similar to the following will be seen: 

{BACKUP}
user@router-re1> show system core-dumps 
Jul 28 09:11:45
-rw-rw-rw-  1 root  wheel  2123272192 Jul 28 08:53 /var/crash/vmcore.live.0
-rw-r--r--  1 root  wheel   13193216 Jul 28 09:05 /var/tmp/ksyncd_10881.core.1627443307.0
-rw-r--r--  1 root  wheel   13336576 Jul 28 08:53 /var/tmp/ksyncd_22562.core.1627442588.0
/var/tmp/pics/*core*: No such file or directory
/var/crash/kernel.*: No such file or directory
/var/jails/rest-api/tmp/*core*: No such file or directory
/tftpboot/corefiles/*core*: No such file or directory
total files: 3

{BACKUP}
user@router-re1>
{MASTER}
user@router-re0> show system core-dumps 
Jul 28 09:02:20
-rw-rw-rw-  1 root  wheel  2152718336 Jul 28 08:53 /var/crash/vmcore.live.0
/var/tmp/*core*: No such file or directory
/var/tmp/pics/*core*: No such file or directory
/var/crash/kernel.*: No such file or directory
/var/jails/rest-api/tmp/*core*: No such file or directory
/tftpboot/corefiles/*core*: No such file or directory
total files: 1

{MASTER}
user@router-re0>

Solution

It is not supported to have one RE with unified-services and the other without it. The two need to be in sync for successful operations.  

To ensure that both REs have unified-services enabled and to enable GRES and USF mode on dual REs, perform the following steps:  

Performing GRES in Unified-Services Enabled Image

  1. ​Load  the image in non-USF mode on both REs.

  2. If GRES and commit-synchronize are enabled, disable the same.

  3. Enable USF on RE1 and reboot RE1.

  4. After RE1 is up, enable USF in RE0 and reboot RE0.

  5. Enable commit-synchronize.

  6. Enable GRES.

  7. Check the redundancy-state in the backup RE. 

  8. Perform GRES.

For more information, see Enabling and Disabling Next Gen Services .