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mabarkdoll
January 11th, 2018, 06:37 PM
Hello, I have an Ubuntu 14.04 run Xen and the VM that I'm having issues with it an Ubuntu 16.04 LTS server that wouldn't boot when I upgraded it to the newest kernel with:


sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

The following is the xen log upon reboot:

$ tailf /var/log/xen/servername.log
Domain 24 needs to be cleaned up: destroying the domain
Done. Rebooting now
libxl: error: libxl_bootloader.c:628:bootloader_finished: bootloader failed - consult logfile /var/log/xen/bootloader.27.log
libxl: error: libxl_exec.c:118:libxl_report_child_exitstatus: bootloader [-1] exited with error status 1
libxl: error: libxl_create.c:1024:domcreate_rebuild_done: cannot (re-)build domain: -3


cat /var/log/xen/bootloader.27.log


Using <class 'grub.GrubConf.Grub2ConfigFile'> to parse /grub/grub.cfg pyGRUB version 0.6
┌───────────────────────────────────────────────── ───────────────────────┐
│ Ubuntu │
│ Ubuntu, with Linux 4.4.0-109-generic │
│ Ubuntu, with Linux 4.4.0-109-generic (recovery mode) │
│ Ubuntu, with Linux 4.4.0-108-generic │
│ Ubuntu, with Linux 4.4.0-108-generic (recovery mode) │
│ Ubuntu, with Linux 4.4.0-104-generic │
│ Ubuntu, with Linux 4.4.0-104-generic (recovery mode) │
│ Ubuntu, with Linux 4.4.0-15-generic │
└───────────────────────────────────────────────── ───────────────────────┘
Use the ^ and ┴ keys to select which entry is highlighted.
Press enter to boot the selected OS, 'e' to edit the
commands before booting, 'a' to modify the kernel arguments
before booting, or 'c' for a command line.














Traceback (most recent call last):
File "/usr/lib/xen-4.4/bin/pygrub", line 905, in <module>
os.write(fd, ostring)
OSError: [Errno 28] No space left on device

I was able to get the vm to boot only by rapidly attempt to access the menu options and boot the old kernel (4.4.0-15-generic). Disk space and inodes seems fine on the host Ubuntu 14.04LTS and Ubuntu 16.04LTS Guest.

Ubuntu 14.04 Host:

root@host:/var/log/xen# df -hFilesystem Size Used Avail Use% Mounted on
udev 197M 12K 197M 1% /dev
tmpfs 42M 1.1M 41M 3% /run
/dev/dm-0 104G 49G 50G 50% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
none 5.0M 0 5.0M 0% /run/lock
none 208M 0 208M 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sda1 236M 40M 184M 18% /boot
root@host:/var/log/xen# df -hi
Filesystem Inodes IUsed IFree IUse% Mounted on
udev 50K 721 49K 2% /dev
tmpfs 52K 849 52K 2% /run
/dev/dm-0 6.6M 86K 6.5M 2% /
none 52K 2 52K 1% /sys/fs/cgroup
none 52K 5 52K 1% /run/lock
none 52K 1 52K 1% /run/shm
none 52K 2 52K 1% /run/user
/dev/sda1 61K 298 61K 1% /boot
root@host:/var/log/xen#


Ubuntu 16.04 PV Guest:

root@guest:~# df -hFilesystem Size Used Avail Use% Mounted on
udev 950M 0 950M 0% /dev
tmpfs 200M 3.1M 197M 2% /run
/dev/mapper/guest--vg-root 47G 4.3G 40G 10% /
tmpfs 997M 0 997M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 997M 0 997M 0% /sys/fs/cgroup
/dev/xvda1 472M 192M 256M 43% /boot
tmpfs 200M 0 200M 0% /run/user/1000
root@www2:~# df -hi
Filesystem Inodes IUsed IFree IUse% Mounted on
udev 238K 406 237K 1% /dev
tmpfs 250K 491 249K 1% /run
/dev/mapper/guest--vg-root 3.0M 177K 2.8M 6% /
tmpfs 250K 1 250K 1% /dev/shm
tmpfs 250K 7 250K 1% /run/lock
tmpfs 250K 16 250K 1% /sys/fs/cgroup
/dev/xvda1 122K 315 122K 1% /boot
tmpfs 250K 4 250K 1% /run/user/1000
root@guest:~#


Here is the guest OS kernels:

root@guest:~# dpkg -l | grep linux-image-
ii linux-image-4.4.0-104-generic 4.4.0-104.127 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii linux-image-4.4.0-108-generic 4.4.0-108.131 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii linux-image-4.4.0-109-generic 4.4.0-109.132 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii linux-image-4.4.0-15-generic 4.4.0-15.31 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii linux-image-extra-4.4.0-104-generic 4.4.0-104.127 amd64 Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP
ii linux-image-extra-4.4.0-108-generic 4.4.0-108.131 amd64 Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP
ii linux-image-extra-4.4.0-109-generic 4.4.0-109.132 amd64 Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP
ii linux-image-extra-4.4.0-15-generic 4.4.0-15.31 amd64 Linux kernel extra modules for version 4.4.0 on 64 bit x86 SMP
ii linux-image-generic 4.4.0.109.114 amd64 Generic Linux kernel image
root@guest:~#

I'm currently able to boot to 4.4.0-15.31

Here is my xen config file that I use to start the vm:

# cat /etc/xen/guest.cfg
# /var/lib/xen/images/ubuntu-netboot/xenial16LTS


name = "guest"


#kernel = "/var/lib/xen/images/ubuntu-netboot/xenial16LTS/vmlinuz"
#ramdisk = "/var/lib/xen/images/ubuntu-netboot/xenial16LTS/initrd.gz"
bootloader = "/usr/lib/xen-4.4/bin/pygrub"


memory = 2048
vcpus = 1




disk = [ '/dev/host-disk2-vg/guest-disk,raw,xvda,rw' ]




#
# Networking
#
vif = [ 'ip=xxx.xxx.xxx.xxx ,mac=AA:BB:CC:DD:EE:FF' ]


#
# Behaviour
#
on_poweroff = 'destroy'
on_reboot = 'restart'
on_crash = 'restart'


I also tried launching the vm with strace output is here: https://pastebin.com/8ctS3TQh

I'm a bit lost as to the cause of this... I was hoping to just upgrade the kernel for meltdown and spetre, but this issue I've never faced before. I think it might be related to pygrub and the new kernel? I don't know for sure though anything I can check to figure this out better? Thanks.

DuckHook
January 11th, 2018, 07:07 PM
I would highly suspect the new kernel as the culprit. Meltdown and Spectre have forced the kernel devs into playing a high stakes game of whack-a-mole for now. I expect a flurry of kernel upgrades over the next few weeks. I'm afraid you will have decide whether covering off Meltdown is worth the loss of your Xen functionality. If not, then sit tight for a kernel fix. In either case, please help the devs by reporting the breakage as a bug on launchpad. Include your trace data in your report.

mabarkdoll
January 11th, 2018, 08:18 PM
I tried to report it but it failed to report...

# ubuntu-bug linux


*** Collecting problem information


The collected information can be sent to the developers to improve the
application. This might take a few minutes.
...............


*** Problem in linux-image-4.4.0-15-generic


The problem cannot be reported:


This is not an official Ubuntu package. Please remove any third party package and try again.


Press any key to continue...


No pending crash reports. Try --help for more information.