systemd-sysv-generator - Unit generator for SysV init scripts
/usr/lib/systemd/system-generators/systemd-sysv-generator
Note: this component is deprecated and scheduled for removal. Please replace remaining SysV init scripts with native unit files.
systemd-sysv-generator is a generator that creates wrapper .service units for System V init[1] scripts in /etc/init.d/* at boot and when configuration of the system manager is reloaded. This allows systemd(1) to support them similarly to native units.
LSB headers[2] in SysV init scripts are interpreted, and the ordering specified in the header is turned into dependencies between the generated unit and other units. The LSB facilities "$remote_fs", "$network", "$named", "$portmap", "$time" are supported and will be turned into dependencies on specific native systemd targets. See systemd.special(7) for more details.
Note that compatibility is quite comprehensive but not 100%, for more details see Incompatibilities with SysV[3].
SysV runlevels have corresponding systemd targets
(runlevelX
.target). The wrapper unit that is generated will be
wanted by those targets which correspond to runlevels for which the
script is enabled.
systemd does not support SysV scripts as part of early boot, so all wrapper units are ordered after basic.target.
systemd-sysv-generator implements systemd.generator(7).
systemd(1), systemd.service(5), systemd.target(5)
System V init
LSB headers
http://refspecs.linuxbase.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
Incompatibilities with SysV
https://www.freedesktop.org/wiki/Software/systemd/Incompatibilities