Devuan aka Debian8 on SysVInit

No, Proxmox VE uses modern systemd. sysvinit is outdatet and cannot be used in a system like Proxmox VE - as a lot of needed packages just provide systemd init scripts
 
SystemD is bad,but SysVinit is deprecated(at least for me).They should have gone with either OpenRC(In Gentoo it works flawlessly for thousands of our servers), or runit(simple and speedy). Instead,they are left in the past. Devuan is really great project but it needs to move forward.