Public bug reported:
The update-grub-legacy-ec2 script (which ships with grub-legacy-ec2,
which is presumably included under cloud-init umbrella) includes a check
to determine whether a kernel is Xen-capable or not. It uses this check
in a feature designed to ignore non-Xen kernels on Xen guests,
presumably as a safety mechanism. The way in which the check is executed
is flawed - it matches against the kernel name. This means that if you
are loading a kernel that has an 'unexpected' name, update-grub-legacy-
ec2 will ignore the new kernel, regardless of whether or not it is
actually Xen-capable. Output looks like this:
Searching for GRUB installation directory ... found: /boot/grub
Searching for default file ... found: /boot/grub/default
Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst
Searching for splash image ... none found, skipping ...
Ignoring non-Xen Kernel on Xen domU host: vmlinuz-3.13.0-36-custom
Found kernel: /boot/vmlinuz-3.13.0-36-generic
Updating /boot/grub/menu.lst ... done
This has been fixed on grub-legacy. Instead of matching the kernel name,
it checks the config for CONFIG_XEN=y. In addition, Linux kernels come
with CONFIG_XEN=y by default for some time now, and it is perfectly safe
to run a Xen-capable kernel on non-Xen hosts.
Steps to reproduce:
1. Compile and generate debs for custom kernel with version string not
including '-generic' or '-virtual'
2. Install debs on ec2 system (ami-a94e0c99)
3. Reboot
Expected results:
System comes up with new kernel
Actual results:
System comes up with old kernel, and new kernel is not present in
/boot/grub/menu.lst
Impact:
Running ami-a94e0c99, and likely many others, a user can not install a custom
kernel without manually editing files. Furthermore, those writes will likely be
overwritten by administrative operations in the future.
Recommendation:
Update detection logic to search for CONFIG_XEN=y in the kernel config, and
remove version string detection.
Please let me know how I can help this along. I can submit a proposed
fix, but am not sure where to send it.
** Affects: cloud-init (Ubuntu)
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to cloud-init in Ubuntu.
https://bugs.launchpad.net/bugs/1379080
Title:
update-grub-legacy-ec2 fails to detect xen kernel
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1379080/+subscriptions
--
Ubuntu-server-bugs mailing list
Ubuntu-server-bugs@lists.ubuntu.com
Modify settings or unsubscribe at:
https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
