Since OpenVZ cannot be upgraded from inside of the VM's client (which I only rent). Is it possible to upgrade to 18.04 LTS from 16.04.5 LTS?
The problem lies on libc/locales
This version of libc requires kernel version 3.2 or later. Plase upgrade your kernel before installing glibc
tried to apt-mark hold libc6 and locales, the do-release-upgrade refuses to continue.