DOKK / manpages / debian 12 / systemd / systemd-sysv-generator.8.en
SYSTEMD-SYSV-GENERATOR(8) systemd-sysv-generator SYSTEMD-SYSV-GENERATOR(8)

systemd-sysv-generator - Unit generator for SysV init scripts

/lib/systemd/system-generators/systemd-sysv-generator

systemd-sysv-generator is a generator that creates wrapper .service units for SysV 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)

1.
SysV init
https://savannah.nongnu.org/projects/sysvinit
2.
LSB headers
http://refspecs.linuxbase.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
3.
Incompatibilities with SysV
https://www.freedesktop.org/wiki/Software/systemd/Incompatibilities
systemd 252