man 8 systemd-sysv-generator

SYSTEMD-SYSV-GENERATOR(8)   systemd-sysv-generator   SYSTEMD-SYSV-GENERATOR(8)

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

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

DESCRIPTION
       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).

SEE ALSO
       systemd(1), systemd.service(5), systemd.target(5)

NOTES
        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                                          SYSTEMD-SYSV-GENERATOR(8)