You can check the log file location in /etc/vz/vz.conf
# Logging parameters
LOGGING=yes
LOGFILE=/var/log/vzctl.log ---> this is the location
vzctl : CT 432 : Creating container private area (centos-6.4-x86_64)
# Logging parameters
LOGGING=yes
LOGFILE=/var/log/vzctl.log ---> this is the location
tail -f /var/log/vzctl.log
vzctl : CT 432 : Creating container private area (centos-6.4-x86_64)
vzctl : CT 432 : Performing postcreate actions
vzctl : CT 432 : CT configuration saved to /etc/vz/conf/432.conf
vzctl : CT 432 : Container private area was created
vzctl : CT 432 : CT configuration saved to /etc/vz/conf/432.conf