upstart(8)
NAME
init - Upstart process management daemon
SYNOPSIS
init [OPTION]...
DESCRIPTION
init is the parent of all processes on the system, it is executed by
the kernel and is responsible for starting all other processes; it is
the parent of all processes whose natural parents have died and it is
responsible for reaping those when they die.
Processes managed by init are known as jobs and are defined by files in
the /etc/init directory. See init(5) for more details on configuring
Upstart.
Events
init(8) is an event-based init daemon. This means that jobs will be
automatically started and stopped by changes that occur to the system
state, including as a result of jobs starting and stopping.
This is different to dependency-based init daemons which start a
specified set of goal jobs, and resolve the order in which they should
be started and other jobs required by iterating their dependencies.
For more information on starting and stopping jobs, as well as emitting
events that will automatically start and stop jobs, see the manual page
for the initctl(8) tool.
The primary event is the startup(7) event, emitted when the daemon has
finished loading its configuration. Other useful events are the
starting(7), started(7), stopping(7) and stopped(7) events emitted as
jobs change state.
Job States
Table 1: Job Goals and State Transitions.
Goal
Current State start stop
waiting starting n/a
starting pre-start stopping
pre-start spawned stopping
spawned post-start stopping
post-start running stopping
running stopping pre-stop / stopping (*)
pre-stop running stopping
stopping killed killed
killed post-stop post-stop
post-stop starting waiting
Key:
(*) If there is a script or exec section and this process is running,
state will be 'pre-stop', else it will be 'stopping'.
Job Lifecycle
Starting a Job
1 Initially the job is "at rest" with a goal of 'stop' and a state of
'waiting' (shown as 'stop/waiting' by the initctl(8) list and status
commands).
2 The goal is changed from 'stop' to 'start' indicating the job is
attempting to start.
3 The state is changed from 'waiting' to 'starting'.
4 The starting(7) event is emitted denoting the job is "about to
start".
5 Any jobs whose 'start on' (or 'stop on') condition would be
satisfied by this job starting are started (or stopped
respectively).
6 The starting(7) event completes.
7 The state is changed from 'starting' to 'pre-start'.
8 If the pre-start stanza exists, the pre-start process is spawned.
9 If the pre-start process fails, the goal is changed from 'start' to
'stop', and the stopping(7) and stopped(7) events are emitted with
appropriate variables set denoting the error.
10 Assuming the pre-start did not fail or did not call "stop", the main
process is spawned.
11 The state is changed from 'pre-start' to 'spawned'.
12 Upstart then ascertains the final PID for the job which may be a
descendent of the immediate child process if expect fork or expect
daemon has been specified.
13 The state is changed from 'spawned' to 'post-start'.
14 If the post-start stanza exists, the post-start process is spawned.
15 The state is changed from 'post-start' to 'running'.
16 The started(7) event is emitted.
For services, when this event completes the main process will now be
fully running. If the job refers to a task, it will now have
completed (successfully or otherwise).
17 Any jobs whose 'start on' (or 'stop on') condition would be
satisfied by this job being started are started (or stopped
respectively).
Stopping a Job
1 Assuming the job is fully running, it will have a goal of 'start'
and a state of 'running' (shown as 'start/running' by the initctl(8)
list and status commands).
2 The goal is changed from 'start' to 'stop' indicating the job is
attempting to stop.
3 The state is changed from 'running' to 'pre-stop'.
4 If the pre-stop stanza exists, the pre-stop process is spawned.
5 The state is changed from 'pre-stop' to 'stopping'.
6 The stopping(7) event is emitted.
7 Any jobs whose 'start on' (or 'stop on') condition would be
satisfied by this job stopping are started (or stopped
respectively).
8 The main process is stopped:
i The signal specified by the kill signal stanza is sent to the
process group of the main process (such that all processes
belonging to the jobs main process are killed). By default this
signal is SIGTERM.
See signal(7) and init(5).
ii Upstart waits for up to "kill timeout" seconds (default 5
seconds) for the process to end.
iii
If the process is still running after the timeout, a SIGKILL
signal is sent to the process which cannot be ignored and will
forcibly stop the processes in the process group.
9 The state is changed from 'killed' to 'post-stop'.
10 If the post-stop stanza exists, the post-stop process is spawned.
11 The state is changed from 'post-stop' to 'waiting'.
12 The stopped(7) event is emitted.
When this event completes, the job is fully stopped.
13 Any jobs whose 'start on' (or 'stop on') condition would be
satisfied by this job being stopped are started (or stopped
respectively).
System V compatibility
The Upstart init(8) daemon does not keep track of runlevels itself,
instead they are implemented entirely by its userspace tools. The
event emitted to signify a change of runlevel is the runlevel(7) event.
For more information see its manual page.
OPTIONS
Options are passed to init(8) by placing them on the kernel command-
line.
--append-confdir directory
Add the specified directory to the default directory or
directories that job configuration files will be read from. This
option may be specified multiple times which will result in job
configuration files being loaded from each directory specified
(which must exist). Directories will be searched for jobs in
the specified order after the default directories have been
searched.
Note that if this option is used in combination with --confdir,
or --prepend-confdir, regardless of the order of the options on
the command-line, the append directories will be added after the
other directories.
--confdir directory
Read job configuration files from a directory other than the
default (/etc/init for process ID 1). This option may be
specified multiple times which will result in job configuration
files being loaded from each directory specified (which must
exist). Directories will be searched for jobs in the specified
order.
In the case that multiple directories specify a job of the same
name, the first job encountered will be honoured.
See section User Session Mode in init(5) for the ordered list of
default configuration directories a Session Init will consider.
--default-console value
Default value for jobs that do not specify a 'console' stanza.
This could be used for example to set the default to 'none' but
still honour jobs that specify explicitly 'console log'. See
init(5) for all possible values of console.
--no-cgroups
Do not honour the cgroup stanza. If specified, this stanza will
be ignored for any job which specifies it: the job processes
will not be placed in the cgroup specified by the stanza and the
job itself will not wait until the cgroup manager has started
before starting itself. See init(5) for further details.
--no-dbus
Do not connect to a D-Bus bus.
--no-inherit-env
Stop jobs from inheriting the initial environment. Only
meaningful when running in user mode.
--logdir directory
Write job output log files to a directory other than
/var/log/upstart (system mode) or $XDG_CACHE_HOME/upstart (user
session mode).
--no-log
Disable logging of job output. Note that jobs specifying
'console log' will be treated as if they had specified 'console
none'. See init(5) for further details.
--no-sessions
Disable chroot sessions.
--no-startup-event
Suppress emission of the initial startup event. This option
should only be used for testing since it will stop the init(8)
daemon from starting any jobs automatically.
--prepend-confdir directory
Add the specified directory to the directory or directories that
job configuration files will be read from. This option may be
specified multiple times which will result in job configuration
files being loaded from each directory specified (which must
exist). Directories will be searched for jobs in the specified
order before the default directories have been searched.
Note that if this option is used in combination with --confdir,
or --append-confdir, regardless of the order of the options on
the command-line, the prepend directories will be added before
the other directories.
--session
Connect to the D-Bus session bus. This should only be used for
testing.
--startup-event event
Specify a different initial startup event from the standard
startup(7).
--user Starts in user mode, as used for user sessions. Upstart will be
run as an unprivileged user, reading configuration files from
configuration locations as per roughly XDG Base Directory
Specification. See init(5) for further details.
-q, --quiet
Reduces output messages to errors only.
-v, --verbose
Outputs verbose messages about job state changes and event
emissions to the system console or log, useful for debugging
boot.
--version
Outputs version information and exits.
NOTES
init is not normally executed by a user process, and expects to have a
process id of 1. If this is not the case, it will actually execute
telinit(8) and pass all arguments to that. See that manual page for
further details. However, if the --user option is specified, it will
run as a Session Init and read alternative configuration files and
manage the individual user session in a similar fashion.
Sending a Session Init a SIGTERM signal is taken as a request to
shutdown due to an impending system shutdown. In this scenario, the
Session Init will emit the session-end event and request all running
jobs stop. It will attempt to honour jobs kill timeout values (see
init(5) for further details). Note however that system policy will
prevail: if jobs request timeout values longer than the system policy
allows for complete system shutdown, it will not be possible to honour
them before the Session Init is killed by the system.
ENVIRONMENT VARIABLES
When run as a user process, the following variables may be used to find
job configuration files:
* $XDG_CONFIG_HOME
* $XDG_CONFIG_DIRS
See User Session Mode in init(5) for further details.
FILES
/etc/init.conf
/etc/init/
$HOME/.init/
$XDG_CONFIG_DIRS/upstart/
$XDG_CONFIG_HOME/upstart/
AUTHOR
Written by Scott James Remnant <scott@netsplit.com>
REPORTING BUGS
Report bugs at <https://launchpad.net/upstart/+bugs>
COPYRIGHT
Copyright 2009-2013 Canonical Ltd.
This is free software; see the source for copying conditions. There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.
SEE ALSO
all-swaps(7), control-alt-delete(7), dbus-daemon(1), dbus-event(7),
dconf-event(7), file-event(7), filesystem(7), init(5), init(8),
initctl(8), keyboard-request(7), local-filesystems(7), mountall(8),
mounted(7), mounting(7), power-status-changed(7),
remote-filesystems(7), runlevel(7), shutdown(8), socket-event(7),
started(7), starting(7), startup(7), stopped(7), stopping(7),
telinit(8), upstart-dbus-bridge(8), upstart-dconf-bridge(8),
upstart-event-bridge(8), upstart-events(7), upstart-file-bridge(8),
upstart-local-bridge(8), upstart-socket-bridge(8),
upstart-udev-bridge(8), virtual-filesystems(7).
Free and Open Source Software