Supervision - init-system and service-manager
Full fledged service-manager and init-system capable of replacing a SystemV or BSD like rc init-system like OpenRC. Yet, it's still simple and efficient as ever!
Note: busybox has an integrated runit suite which has
the same command line options as runsvdir,sv,runsv,...; so support for this is
almost guaranted to function as expected. Just install busybox symlinks, and voila!
Full-featured and yet simple and efficient init-system and service-manager with service dependencies, standard service commands and extra service commands, virtual service and service instances and read-only rootfs support to name a few.
BOOT AND SHUTDOWN STATS:
A comlete system, Linux in this test bed,--with rootfs on LVM(2) on top of dm-crypt LUKS, ZFS on top of dm-crypt LUKS, /(var/)tmp on ZRAM backed devices, a few union filesystem (OverlayFS+SquashFS),--with 52 system services for short, can boot or shut down in 11 seconds thanks to supervision parallel service management! Now if udev is used, add 5 seconds to boot up... or it could be even worse depending on the number of devices. dependencies.
./configure --build=x86_64-pc-linux-gnu --libdir=/lib64
- add `--enable-sysvinit` to get an additional sysvinit compatibility service;
- add `--enable-runit` to get Runit init-stage-[123]; and likewise
- add `--enable-s6` for S6 init-stage-[123]; and then
- (other standard options are available, see `--help`);
- WARNING: this package should be istalled in a non prefixed installation, so,
avoid using `--libdir=/usr/lib64` or similar to have system utilities in rootfs;
make -j2 to build; and finaly
make DESTDIR=/tmp installl to install.
And do not forget to run ${LIBDIR}/sv/sbin/sv-config --config ARG afterwards!
Or, if updating an old installation do not forget to run
${LIBDIR}/sv/sbin/sv-config --update afterwards!
If runit was enabled, copy /usr/share/supervision/runit to /etc;
If s6 was enabled, copy /usr/share/supervision/s6 to /etc.
The recommanded way to use this package for service management is to use
${LIBDIR}/sv/sh/sv-rc.sh --(sysinit|default|shutdown) to start particular init
stage or runlevel when using a supported supervisor. Or else, sv-rc(8) like
any SystemV or BSD like system rc(8).
And then use
sv-run [OPTIONS] SERVICE COMMAND [ARGUMENTS] to manage particular services;
or rather use ${LIBDIR}/sv/sbin/service [OPTIONS] SERVICE COMMAND for
SystemV compatibility.
NOTE: That symlink can be copied or moved to ${EXEC_PREFIX}/sbin if
necessary to ease administration and if there is no other SystemV binary
installed in the system.
Or else, use the magic svscan mode to supervise /service/ and then
set SV_SYSTEM="supervision" in /etc/sv.conf configuration file and finaly use
sv-rc default to supervise daemons.
Support for containrization solutions or subsystems is available via keywords
usage (see KEYWORDS subsection in supervision(5) and /etc/sv.conf for more
information) for docker, LXC, jail, systemd-nspawn, UREFIX installation,
supervision, UML, VServer and XEN.
Either the subsystem will be auto detected or use /etc/sv.conf to set a particular
subsystem with SV_SYSTEM="${SUBSYSTEM}" configuration variable...
SV_SYSTEM="supervision" for daemon supervision only;
SV_SYSTEM="prefix" for an isolated chrooted environment;
SV_SYSTEM="docker" for docker containers et al.
Services that have the subsystem keyword will not be started in that particular
subsystem environment.
To have the supervisor ({damontools[-encore],runit,s6}) executed as PID 1...
Just setup the container or subsystem; once done, use something like
the following for docker: docker run [OPTIONS] --env container=docker --tmpfs /run IMAGE /lib64/sv/sh/sv-init.sh --default or; and voila! the supervisor will be executed
as PID 1 and another process will handle service management to setup the container.
And then... a bit more, new supervision services can be easily added by
running ${LIBDIR}/sv/sbin/sv-config [--log] ${SERVICE} new (--log argument
would add a log directory for the service); and then edit
/etc/sv/${SERVICE}/OPTIONS before launching the service.
See supervision(5), sv-rc(8), sv-shutdown(8) and or sv-run(8) man page
for more information.
Supervision requires standard coreutils, grep, procps,
sed and a (POSIX) shell.
POSIX shell compliance is not enforced because it should not be especially when
using OpenBSD version of ksh,
see builtins(8) manual page for more information. Otherwise, everything was
tested with bash and
zsh and work as expected.
Optional SysVinit for compatibilty with SysVinit's utilities is supported.
Else, sv-shutdown(8) has a BSD like shutdown(8), reboot(8), halt(8) and
poweroff(8) behaviour than the SysVinit utilities.
Thanks to:
Avery Payne (original supervision-scripts); And others.
Distributed under the 2-clause/new/simplifed BSD License