Using the vzsplit command, you can create configurations for containers that would take a specific fraction of the hardware node resources. For example, to create a configuration myconf for up to 20 containers:
# vzsplit -n 20 -f myconf
Config /etc/vz/conf/ve-myconf.conf-sample was created
The configuration is calculated based on the hardware node resources. You can now use the --config myconf option of the prlctl create command to create containers based on this configuration.