Symptoms
Upgrade core log show message:
Installation of kernel-default-4.12.14-122.159.1.x86_64 failed:
Error: Subprocess failed. Error: RPM failed: Installing package kernel-default-4.12.14-122.159.1.x86_64 needs 6MB on the /boot filesystem.
Cause
The /boot need at lease 80 MB free to install the kernel. If you have less than 80 MB, it fails.
Resolution
1. Login to all SRM servers before the upgrade.
2. Run command: df -h.
3. Verify if /boot has more than 80 MB free.
4. If you have less than 80 MB please open case with support to assist this issue.