container doesn't start after upgrade

[Frakir]

I have lxc-containers with Ubuntu 14.04.
After do-release-upgrade to Ubuntu 16.04 they refused to start.
I tryed it on
pve-manager/5.2-6/bcd5f008 (running kernel: 4.15.18-1-pve
and on
pve-manager/5.2-6/bcd5f008 (running kernel: 4.15.18-1-pve)
I tryed reboot proxmox but it didn't help.

root@p4:~# pct start 450
Job for pve-container@450.service failed because the control process exited with error code.
See "systemctl status pve-container@450.service" and "journalctl -xe" for details.
command 'systemctl start pve-container@450' failed: exit code 1

In the logs just
aug 15 11:53:23 p4 lxc-start[13834]: lxc-start: 450: lxccontainer.c: wait_on_daemonized_start: 824 Received container state "ABORTING" instead of "RUNNING"
aug 15 11:53:23 p4 lxc-start[13834]: The container failed to start.

When I try lxc-start -n 450 -F I see the error:
862 Failed to create cgroup "/sys/fs/cgroup/freezer//lxc/450"
lxc-start: 450: cgroups/cgfsng.c: create_path_for_hierarchy: 1752 Path "/sys/fs/cgroup/memory//lxc/450-1" already existed.
lxc-start: 450: cgroups/cgfsng.c: cgfsng_create: 1862 Failed to create cgroup "/sys/fs/cgroup/memory//lxc/450-1"
lxc-start: 450: cgroups/cgfsng.c: create_path_for_hierarchy: 1752 Path "/sys/fs/cgroup/memory//lxc/450-2" already existed.
lxc-start: 450: cgroups/cgfsng.c: cgfsng_create: 1862 Failed to create cgroup "/sys/fs/cgroup/memory//lxc/450-2"
lxc-start: 450: cgroups/cgfsng.c: create_path_for_hierarchy: 1752 Path "/sys/fs/cgroup/memory//lxc/450-3" already existed.
lxc-start: 450: cgroups/cgfsng.c: cgfsng_create: 1862 Failed to create cgroup "/sys/fs/cgroup/memory//lxc/450-3"
lxc-start: 450: cgroups/cgfsng.c: create_path_for_hierarchy: 1752 Path "/sys/fs/cgroup/memory//lxc/450-4" already existed.
lxc-start: 450: cgroups/cgfsng.c: cgfsng_create: 1862 Failed to create cgroup "/sys/fs/cgroup/memory//lxc/450-4"
lxc-start: 450: sync.c: __sync_wait: 57 An error occurred in another process (expected sequence number 7)
lxc-start: 450: start.c: __lxc_start: 1883 Failed to spawn container "450"
The container failed to start.

What's wrong and how to get the container start?

 

[Frakir]

I removed the bad container and created a new one, with Ubuntu 16.04-template.
When I start it, pct list refuses to work:
root@p4:/zfs2/subvol-450-disk-1/root# pct list
can't open '/sys/fs/cgroup/memory/lxc/450/ns/memory.stat' - No such file or directory
And there are no containers in the web-interface.
lxc-ls works.
Recreating containers is not the solution, I have to upgrade a lot of ther containers. But it show that there are some troubles with cgroups after upgrade.

What's wrong with the upgrade? How to fix it?

 

[theendcomplete]

I've got the same error
Does anyone have a solution?..