Article ID: 7039, created on Dec 21, 2009, last review on Oct 23, 2014

  • Applies to:
  • Virtuozzo
  • Virtuozzo containers
  • Virtuozzo hypervisor

Symptoms

In some rare cases online migration fails with the following error message in the system logs of the hardware node (/var/log/messages, /var/log/vzctl.log):

vzctl : Can not dump Container: Invalid argument
vzctl : Error: d_path is invisible /var/named/run-root/proc
vzctl : Checkpointing of Container failed
vzctl failed, exitcode=16
can not dump CT#101 : vzctl failed, exitcode=16
This CT can't be migrated online at the moment. Try offline migration.

Cause

This problem is happening because of the named service proc mounting issue. Even if you try to stop the named service, the mounts will not unmount:

~# vzctl exec2 101 /etc/init.d/named stop
Stopping named: .                        [  OK  ]

~# vzctl exec2 101 grep named /proc/mounts
proc /var/named/run-root/proc proc rw 0 0
vzfs /var/named/run-root/var/run/dbus vzfs rw 0 0
proc /var/named/run-root/proc proc rw 0 0
vzfs /var/named/run-root/var/run/dbus vzfs rw 0 0
proc /var/named/run-root/proc proc rw 0 0
vzfs /var/named/run-root/var/run/dbus vzfs rw 0 0

Resolution

In this case it is necessary to unmount these mounts:

~# vzctl enter 101
~# umount /var/named/run-root/proc
~# umount /var/named/run-root/proc
~# umount /var/named/run-root/proc
~# umount /var/named/run-root/var/run/dbus
~# umount /var/named/run-root/var/run/dbus
~# umount /var/named/run-root/var/run/dbus

After that please start named service inside the container again, so the mount points will be created properly:

~# vzctl exec2 101 /etc/init.d/named start
 Starting named: [  OK  ]

~# vzctl exec2 101 grep named /proc/mounts
proc /var/named/run-root/proc proc rw 0 0
vzfs /var/named/run-root/var/run/dbus vzfs rw 0 0

Then please try the on-line migration again.

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