If you manage several OpenVZ containers, here is a simple bash script to keep the OpenVZ containers upto date.
#!/bin/bash
# vzyum_updates.sh
# updates VEs
VE_LIST=$(/usr/sbin/vzlist -H -o veid | grep -v Warning)
for VE in ${VE_LIST}
do
/usr/bin/vzyum $VE update
done
exit 0