Open Stack

Hi Jim

So the base F21 image (Fedora 21 (PVHVM)) has an extlinux.conf in
/boot/extlinux.conf

---
[root at cloud-server-01 boot]# cat extlinux.conf
TIMEOUT 1
ONTIMEOUT linux

LABEL linux
      KERNEL /boot/vmlinuz-3.18.3-201.fc21.x86_64
      APPEND initrd=/boot/initramfs-3.18.3-201.fc21.x86_64.img root=/dev/xvda1
---

The format of this causes a problem with "yum update kernel" as the
"grubby" command it runs mangles the file.  It copies the APPEND line
to the new kernel's config (giving it the wrong initrd) and doesn't
update the default (that's why it still boots ... but with the old
kernel)

So I tested this with a modified extlinux.conf that looks like

---
[root at cloud-server-01 boot]# cat extlinux.conf
TIMEOUT 1

default linux

LABEL linux
      KERNEL /boot/vmlinuz-3.18.3-201.fc21.x86_64
      APPEND root=/dev/xvda1
      initrd /boot/initramfs-3.18.3-201.fc21.x86_64.img

---

note differences are a "default" statement (which gets updated to the
new kernel) and the initrd is separate to appended options.

After "yum update" the file gets re-written correctly with the new
kernel as the default

---
TIMEOUT 1

default Fedora (3.18.7-200.fc21.x86_64) 21 (Twenty One)

LABEL Fedora (3.18.7-200.fc21.x86_64) 21 (Twenty One)
      KERNEL /boot/vmlinuz-3.18.7-200.fc21.x86_64
      APPEND root=/dev/xvda1 LANG=en_US.UTF-8
      initrd /boot/initramfs-3.18.7-200.fc21.x86_64.img
LABEL linux
      KERNEL /boot/vmlinuz-3.18.3-201.fc21.x86_64
      APPEND root=/dev/xvda1
      initrd /boot/initramfs-3.18.3-201.fc21.x86_64.img
---

and it seems to boot fine with the new kernel.

We're fairly certain that the kernel version is causing issues for
successful runs in upstream infra testing, so we're keen to get the
image updated.

-i