<s>
runit	B-Device
is	O
an	O
init	B-Operating_System
and	O
service	O
management	O
scheme	O
for	O
Unix-like	O
operating	O
systems	O
that	O
initializes	O
,	O
supervises	B-General_Concept
,	O
and	O
ends	O
processes	O
throughout	O
the	O
operating	O
system	O
.	O
</s>
<s>
Runit	B-Device
is	O
a	O
reimplementation	O
of	O
the	O
daemontools	B-Device
process	B-General_Concept
supervision	I-General_Concept
toolkit	O
that	O
runs	O
on	O
many	O
Linux-based	O
operating	O
systems	O
,	O
as	O
well	O
as	O
BSD	O
,	O
and	O
Solaris	B-Application
operating	I-Application
systems	I-Application
.	O
</s>
<s>
Runit	B-Device
features	O
parallelization	O
of	O
the	O
start	O
up	O
of	O
system	O
services	O
,	O
which	O
can	O
speed	O
up	O
the	O
boot	B-Operating_System
time	I-Operating_System
of	O
the	O
operating	O
system	O
.	O
</s>
<s>
When	O
running	O
as	O
an	O
init	B-Operating_System
daemon	B-Operating_System
,	O
Runit	B-Device
is	O
the	O
direct	O
or	O
indirect	O
ancestor	B-Operating_System
of	O
all	O
other	O
processes	O
.	O
</s>
<s>
It	O
is	O
the	O
first	O
process	B-Operating_System
started	O
during	O
booting	B-Operating_System
,	O
and	O
continues	O
running	O
until	O
the	O
system	O
is	O
shut	O
down	O
.	O
</s>
<s>
It	O
is	O
often	O
used	O
with	O
other	O
init	B-Operating_System
systems	O
as	O
a	O
separate	O
service	O
manager	O
.	O
</s>
<s>
In	O
the	O
service	O
manager	O
role	O
,	O
it	O
can	O
be	O
used	O
by	O
unprivileged	O
users	O
to	O
orchestrate	O
personal	O
services	O
,	O
as	O
well	O
as	O
by	O
root	O
to	O
manage	O
services	O
not	O
otherwise	O
managed	O
by	O
the	O
init	B-Operating_System
system	O
currently	O
in	O
use	O
.	O
</s>
<s>
Runit	B-Device
focuses	O
on	O
being	O
a	O
small	O
,	O
modular	O
,	O
and	O
portable	B-Application
codebase	O
.	O
</s>
<s>
In	O
the	O
init	B-Operating_System
role	O
,	O
Runit	B-Device
is	O
split	O
into	O
three	O
stages	O
:	O
one	O
time	O
initialization	O
,	O
process	B-General_Concept
supervision	I-General_Concept
,	O
and	O
halting	O
or	O
rebooting	O
.	O
</s>
<s>
While	O
the	O
first	O
and	O
third	O
stages	O
must	O
be	O
adapted	O
to	O
the	O
specific	O
operating	O
system	O
they	O
are	O
running	O
on	O
,	O
the	O
second	O
stage	O
is	O
portable	B-Application
across	O
all	O
POSIX	O
compliant	O
operating	O
systems	O
.	O
</s>
<s>
The	O
3	O
stages	O
can	O
be	O
configured	O
through	O
3	O
executable	O
files	O
(	O
they	O
are	O
usually	O
shell	B-Device
scripts	O
)	O
named	O
,	O
respectively	O
,	O
1	O
,	O
2	O
,	O
and	O
3	O
.	O
</s>
<s>
Stage	O
2	O
usually	O
invokes	O
a	O
binary	O
named	O
runsvdir	O
,	O
which	O
is	O
the	O
process	B-Operating_System
responsible	O
for	O
global	O
daemon	B-Operating_System
management	O
:	O
for	O
every	O
daemon	B-Operating_System
it	O
finds	O
in	O
a	O
folder	O
passed	O
to	O
it	O
by	O
argument	O
,	O
it	O
then	O
spawns	O
an	O
individual	O
watchdog	O
,	O
each	O
of	O
those	O
starts	O
a	O
daemon	B-Operating_System
(	O
and	O
a	O
logger	O
service	O
eventually	O
associated	O
to	O
it	O
)	O
and	O
restarts	O
it	O
if	O
it	O
dies	O
.	O
</s>
<s>
In	O
case	O
a	O
daemon	B-Operating_System
is	O
added	O
or	O
removed	O
,	O
it	O
kills	O
the	O
watchdog	O
or	O
starts	O
a	O
new	O
one	O
.	O
</s>
<s>
Executable	O
files	O
with	O
specific	O
names	O
are	O
used	O
to	O
describe	O
the	O
various	O
phases	O
of	O
the	O
daemon	B-Operating_System
's	O
life	O
(	O
run	O
,	O
check	O
,	O
finish	O
,	O
...	O
)	O
,	O
it	O
can	O
intercept	O
signals	O
sent	O
and	O
run	O
by	O
specific	O
scripts	O
if	O
they	O
exist	O
,	O
and	O
named	O
pipes	O
are	O
created	O
to	O
expose	O
interfaces	O
to	O
control	O
the	O
daemon	B-Operating_System
.	O
</s>
<s>
Runit	B-Device
can	O
be	O
used	O
either	O
as	O
a	O
drop-in	O
replacement	O
for	O
sysvinit	O
,	O
or	O
as	O
a	O
service	O
supervisor	O
(	O
with	O
sysvinit	O
as	O
the	O
parent	O
PID	B-Operating_System
1	O
process	B-Operating_System
which	O
runs	O
processes	O
specified	O
by	O
the	O
inittab	O
file	O
,	O
or	O
some	O
other	O
init	B-Operating_System
system	O
)	O
.	O
</s>
<s>
The	O
RubyWorks	O
stack	O
of	O
software	O
able	O
to	O
run	O
Ruby	B-Application
on	I-Application
Rails	I-Application
incorporated	O
Runit	B-Device
into	O
its	O
suite	O
.	O
</s>
<s>
Runit	B-Device
is	O
the	O
default	O
init	B-Operating_System
system	O
of	O
:	O
</s>
<s>
Runit	B-Device
is	O
an	O
"	O
officially	O
"	O
available	O
init	B-Operating_System
system	O
for	O
:	O
</s>
