Upstart process management daemon
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.
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.
See upstart-events(7) for a summary of well-known events.
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 are passed to init(8) by placing them on the kernel command-line.
Read job configuration files from a directory other than the default (/etc/init for process ID 1).
When running as process ID 1, the last directory specified will be used.
In user session mode, multiple directories will be honoured and job configuration files loaded from the directories in the order specified.
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.
Do not connect to a D-Bus bus.
Stop jobs from inheriting the initial environment. Only meaningful when running in user mode.
Write job output log files to a directory other than /var/log/upstart (system mode) or $XDG_CACHE_HOME/upstart (user session mode).
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.
Disable chroot sessions.
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.
Connect to the D-Bus session bus. This should only be used for testing.
Specify a different initial startup event from the standard startup(7).
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.
Reduces output messages to errors only.
Outputs verbose messages about job state changes and event emissions to the system console or log, useful for debugging boot.
Outputs version information and exits.
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.
When run as a user process, the following variables may be used to find job configuration files:
See User Session Mode in init(5) for further details.
Written by Scott James Remnant <[email protected]>
Report bugs at <https://launchpad.net/upstart/+bugs>
Copyright © 2009-2012 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.