I am taking the Linux Mint shell server, mint.eskimo.com, down for an upgrade from Serena 18.1 to Sonya 18.2. Serena has been particularly problematic with NIS always failing to bind because the ordering of applications starting is not right in systemd, in particular systemd does not wait for portmap to start before trying to start ypbind. Early versions of Ubuntu with systemd had similar issues, I am hoping 18.2 will resolve this.
Because Mint online upgrades generally do not work well, particularly when third party repositories are concerned, and because there has been a change of hardware architecture from an i7-2600 to an i7-6850k which supports some additional instructions, I am doing a fresh install which will require recompiling some third party apps. So it will likely be down most of this evening.
Please consider using debian or ubuntu as alternatives, like Mint they are debian or debian derived but generally work better. Hopefully Sonya will function better.