What to do if the virtual machine does not start in Xen Server 6.2?

Question

Xen

I am planning to migrate from old versions of Xen Server 6.2 to 6.5 (I know that 7.0 has already been released)
I take a snapshot, export it to a backup file, copy it to another server, 6.5 everything goes well, but the machine does not start. Loader error. And for the life of me, the motives are incomprehensible.

"Failed","Starting VM '******-SN-2016-06-02'
Internal error: xenopsd internal error: VM = 1e1732a1-48ec-0a66-8091-3a2a4824db31; domid = 6; Bootloader.Bad_error Using <class 'grub.GrubConf.Grub2ConfigFile'> to parse /grub/grub.cfg
WARNING:root:Unknown directive load_video
WARNING:root:Unknown directive terminal_output
WARNING:root:Unknown image directive load_video
WARNING:root:Unknown image directive load_video
WARNING:root:Unknown directive source
Traceback (most recent call last):
  File "/usr/bin/pygrub", line 966, in ?
    output_directory, not_really)
  File "/usr/bin/pygrub", line 781, in copy_from_image
    dir=output_directory)
  File "/usr/lib/python2.4/tempfile.py", line 302, in mkstemp
    return _mkstemp_inner(dir, prefix, suffix, flags)
  File "/usr/lib/python2.4/tempfile.py", line 236, in _mkstemp_inner
    fd = _os.open(file, flags, 0600)
OSError: [Errno 2] No such file or directory: '/var/run/xend/boot/boot_kernel.q93Gza'

Time: 00:00:03","***","Jun 2, 2016 10:49 PM"

At first, I thought maybe the hornbeam broke during the update and I didn’t notice, strange, but still I reinstalled and regenerated all the configs, booting from the live sd and performing the operations of mounting and reinstalling the kernel. But still got the same error. I started digging deeper and trying to load the minimum configuration, the hornbeam got rid of all the warnings in the log above, but everything fell into the python script at the hypervisor level. - and then I realized that Xen is most likely to blame.
Just in case, here is the grab config,

# DO NOT EDIT THIS FILE

# Здесь указана часть конфига, полная доступна по ссылке: http://pastebin.com/xt1vRgNq

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-amd64' --class debian --class gnu-linux --class gnu --class os {
  load_video
  insmod gzio
  insmod part_msdos
  insmod ext2
  set root='(hd0,msdos1)'
  search --no-floppy --fs-uuid --set=root 6495c800-bf38-4b63-b873-d46676f6d5c8
  echo	'Loading Linux 3.2.0-4-amd64 ...'
  linux	/vmlinuz-3.2.0-4-amd64 root=/dev/mapper/nr-root ro console=hvc0 quiet
  echo	'Loading initial ramdisk ...'
  initrd	/initrd.img-3.2.0-4-amd64
}
menuentry 'Debian GNU/Linux, with Linux 3.2.0-4-amd64 (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
  load_video
  insmod gzio
  insmod part_msdos
  insmod ext2
  set root='(hd0,msdos1)'
  search --no-floppy --fs-uuid --set=root 6495c800-bf38-4b63-b873-d46676f6d5c8
  echo	'Loading Linux 3.2.0-4-amd64 ...'
  linux	/vmlinuz-3.2.0-4-amd64 root=/dev/mapper/nr-root ro single console=hvc0
  echo	'Loading initial ramdisk ...'
  initrd	/initrd.img-3.2.0-4-amd64
}
### END /etc/grub.d/10_linux ###

There are ideas how it is possible to launch all this good. In fact, if the virtual machine turns off, it will not be able to start, which is fraught with problems. All experiments can be carried out on the same iron machine with a snapshot that does not start =(

Answer 1

If you suddenly see a similar error, this command helps: mkdir -p /var/run/xend/boot/
Only now the question is why it disappeared if no actions were taken on the server.