enter into VE NNN failed
Unable to open pty: No such file or directory

[...]
Running Transaction
  Installing: udev                         ######################### [1/2] 
  Removing  : vzdev                        ######################### [2/2]

Installed: udev.x86_64 0:095-14.9.el5
Complete!

# rpm -q --provides vzdev
dev  
udev = 084-13
vzdev = 3.3.13-1.4.swsoft

#!/bin/bash
#
# This script creates all missing devices on the VPS (openVZ),
# that are removed do updates on udev
# @author       Claudio Thomas, 2009
# @filename     /etc/rc.d/make_vzdev
#
# At first check if recreation is needed
if [ -c /dev/ptyp0 ]; then
        # All seems to be ok, so we are already finished
        exit 0;
fi
# VPS seems to forgot all vzdevices
# force recreation

# ptmx and pty's are needed to enter the VPS with vzctl enter <VPS> and other, so this are the first we will need!
MAKEDEV /dev/ptmx
MAKEDEV /dev/pty
# .../dev/pzyzf

# weitere
MAKEDEV /dev/core
# MAKEDEV /dev/fd would create a lot more than we need, so only make a symlink
ln -sf /proc/self/fd /dev/fd
MAKEDEV /dev/full
MAKEDEV /dev/kmem
MAKEDEV /dev/mem
MAKEDEV /dev/port
MAKEDEV /dev/ptmx
MAKEDEV /dev/ram
#... and also many other /dev/ram...
MAKEDEV /dev/random
MAKEDEV /dev/shm
# is needed for example ssh-connections!
MAKEDEV /dev/urandom
MAKEDEV /dev/zero