systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
list-units [PATTERN...] List loaded units
This container won't start after exhausting its memory. There are no relevant or helpful messages in dmesg or vzctl.log as well. Standard troubleshooting such as disabling PPP etc has not helped.
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Locked by: pid 166029, cmdline vzctl start 888171
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container already locked
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container was stopped