Provided by:
upstart_1.5-0ubuntu5_i386 
NAME
init - Upstart init daemon job configuration
SYNOPSIS
/etc/init/
Default location of system job configuration files.
$HOME/.init/
Default location of user job configuration files.
DESCRIPTION
On startup, the Upstart init(8) daemon reads its job configuration from
files in the /etc/init/ directory, and watches for future changes to
these files using inotify(7).
If D-Bus has been configured to allow non-privileged users to invoke
all Upstart D-Bus methods, Upstart is also able to manage User Jobs.
See User Jobs for further details.
To be considered by Upstart, files in this directory must have a
recognized suffix and may also be present in sub-directories. There
are two recognized suffixes:
o Files ending in .conf are called configuration files, or simply
"conf files" for short. These are the primary vehicle for
specifying a job.
o Files ending in .override are called override files. If an
override file is present, the stanzas it contains take precedence
over those equivalently named stanzas in the corresponding
configuration file contents for a particular job. The main use for
override files is to modify how a job will run without having to
modify its configuration file directly. See the section Override
File Handling below for further details.
A job can thus be defined by either:
o A single configuration file.
o A single configuration file and a single override file.
Unless explicitly stated otherwise, any reference to a jobs
configuration can refer both to a configuration file or an override
file.
Each configuration file defines the template for a single service
(long-running process or daemon) or task (short-lived process).
Note that a configuration file is not itself a job: it is a description
of an environmenta job could be run in. A job is the runtime
embodiment of a configuration file.
The configuration file name as displayed by Upstart and associated
tooling is taken from its relative path within the directory without
the extension. For example a configuration file /etc/init/rc-
sysinit.conf is named rc-sysinit, while a configuration file
/etc/init/net/apache.conf is named net/apache. Since override files
only modify the way a configuration file is interpreted, they are not
named.
Configuration files are plain text and should not be executable.
User Jobs
A User Job is a job configuration file created by a non-privileged user
in their $HOME/.init/ directory. Job configuration files in this
directory have the same syntax as system job configuration files.
Files in this directory will be read and an inotify(7) watch created
the first time a user runs initctl(8).
Any user can create user jobs, but that user can control only jobs they
create.
Users are able to manage their jobs using the standard initctl(8)
facility.
Note that stanzas which manipulate resources limits may cause a job to
fail to start should the value provided to such a stanza attempt to
exceed the maximum value the users privilege level allows.
Note that a user job configuration file cannot have the same name as a
system job configuration file.
Chroot Support
Upstart is able to manage jobs within a chroot(2). To control jobs
within the chroot environment, use the standard initctl(8) facility.
Note that it is not necessary to install D-Bus within the chroot (in
fact it is not recommended).
Note that User Jobs can be created within a chroot environment.
Configuration File Format
Each line begins with a configuration stanza and continues until either
the end of the line or a line containing a closing stanza. Line breaks
within a stanza are permitted within single or double quotes, or if
preceeded by a blackslash.
If a stanza is duplicated, the last occurence will be used.
Unrecognized stanzas will generate parse errors, which will stop a job
from running.
Stanzas and their arguments are delimited by whitespace, which consists
of one or more space or tab characters which are otherwise ignored
unless placed within single or double quotes.
Comments begin with a `#' and continue until the end of the line.
Blank lines and lines consisting only of whitespace or comments are
ignored.
Process definition
The primary use of jobs is to define services or tasks to be run by the
init(8) daemon. Each job may have one or more different processes run
as part of its lifecycle, with the most common known as the main
process.
The main process is defined using either the exec or script stanzas,
only one of which is permitted. These specify the executable or shell
script that will be run when the job is considered to be running. Once
this process terminates, the job stops.
All processes are run with the full job environment available as
environment variables in their process.
exec COMMAND [ ARG ]...
This stanza defines the process to be run as the name of an
executable on the filesystem, and zero or more arguments to be
passed to it. Any special characters, e.g. quotes or `$'
specified will result in the entire command being passed to a
shell for expansion.
exec /usr/sbin/acpid -c $EVENTSDIR -s $SOCKET
script ... end script
This stanza defines the process to be run as a shell script that
will be executed using sh(1). The -e shell option is always
used, so any command that fails will terminate the script.
The script stanza appears on its own on a line, the script is
everything up until the first end script stanza appearing on its
own on a line.
script
dd bs=1 if=/proc/kmsg of=$KMSGSINK
exec /sbin/klogd -P $KMSGSINK
end script
There are an additional four processes that may be run as part of the
job's lifecycle. These are specified as the process name, followed by
an exec or script stanza.
pre-start exec|script...
This process will be run after the job's starting(7) event has
finished, but before the main process is run. It is typically
used to prepare the environment, such as making necessary
directories.
post-start exec|script...
This process will be run before the job's started(7) event is
emitted, but after the main process has been spawned. It is
typically used to send necessary commands to the main process,
or to delay the started(7) event until the main process is ready
to receive clients.
pre-stop exec|script...
This process is run if the job is stopped by an event listed in
its stop on stanza or by the stop(8) command. It will be run
before the job's stopping(7) event is emitted and before the
main process is killed. It is typically used to send any
necessary shutdown commands to the main process, and it may also
call the start(8) command without arguments to cancel the stop.
post-stop exec|script...
This process is run after the main process has been killed and
before the job's stopped(7) event is emitted. It is typically
used to clean up the environment, such as removing temporary
directories.
All of these processes, including the main process, are optional.
Services without a main process will appear to be running until they
are stopped: this is commonly used to define states such as runlevels.
It is permissable to have no main process, but to have pre-start and
post-stop processes for the state.
pre-start exec ifup -a
post-stop exec ifdown -a
Event definition
Jobs can be manually started and stopped at any time by a system
adminstrator using the start(8) and stop(8) tools, however it is far
more useful for jobs to be started and stopped automatically by the
init(8) daemon when necessary.
This is done by specifying which events should cause your job to be
started, and which cause your process to be stopped again.
The set of possible events is limitless, however there are a number of
standard events defined by the init(8) daemon and telinit(8) tools that
you will want to use.
When first started, the init(8) daemon will emit the startup(7) event.
This will activate jobs that implement System V compatibility and the
runlevel(7) event. As jobs are started and stopped, the init(8) daemon
will emit the starting(7), started(7), stopping(7) and stopped(7)
events on their behalf.
start on EVENT [[KEY=]VALUE]... [and|or...]
The start on stanza defines the set of events that will cause
the job to be automatically started. Each EVENT is given by its
name. Multiple events are permitted using the and & or
operators, and complex expressions may be performed with
parentheses (within which line breaks are permitted).
You may also match on the environment variables contained within
the event by specifying the KEY and expected VALUE. If you know
the order in which the variables are given to the event you may
omit the KEY.
VALUE may contain wildcard matches and globs as permitted by
fnmatch(3) and may expand the value of any variable defined with
the env stanza.
Negation is permitted by using != between the KEY and VALUE.
start on started gdm or started kdm
start on device-added SUBSYSTEM=tty DEVPATH=ttyS*
start on net-device-added INTERFACE!=lo
stop on EVENT [[KEY=]VALUE]... [and|or...]
The stop on stanza defines the set of events that will cause the
job to be automatically stopped. It has the same syntax as
start on.
VALUE may additionally expand the value of any variable that
came from the job's start environment (either the event or the
command that started it).
stop on stopping gdm or stopping kdm
stop on device-removed DEVPATH=$DEVPATH
manual This stanza will disregard any previously seen start on
definition. By adding this stanza on any line below the start
on definition, it provides the ability to stop a job from being
automatically started. When specified, the only way to start
such a job is via start (8).
Job environment
Each job is run with the environment from the events or commands that
started it. In addition, you may define defaults in the job which may
be overridden later and specify which environment variables are
exported into the events generated for the job.
The special UPSTART_EVENTS environment variable contains the list of
events that started the job, it will not be present if the job was
started manually.
In addition, the pre-stop and post-stop scripts are run with the
environment of the events or commands that stopped the job. The
UPSTART_STOP_EVENTS environment variable contains the list of events
that stopped the job, it will not be present if the job was stopped
manually.
All jobs also contain the UPSTART_JOB and UPSTART_INSTANCE environment
variables, containing the name of the job and instance. These are
mostly used by the initctl(8) utility to default to acting on the job
the commands are called from.
env KEY[=VALUE]
Defines a default environment variable, the value of which may
be overriden by the event or command that starts the job. If
'KEY=VALUE' is specified, the variable KEY is given the value
VALUE. If only 'KEY' is given, then the value is taken from the
init(8) daemon's own environment.
export KEY
Exports the value of an environment variable into the
starting(7), started(7), stopping(7) and stopped(7) events for
this job and to all resultant events (not just those relating to
the current job).
Services, tasks and respawning
Jobs are services by default. This means that the act of starting the
job is considered to be finished when the job is running, and that even
exiting with a zero exit status means the service will be respawned.
task This stanza may be used to specify that the job is a task
instead. This means that the act of starting the job is not
considered to be finished until the job itself has been run and
stopped again, but that exiting with a zero exit status means
the task has completed successfully and will not be respawned.
The start(8) command, and any starting(7) or stopping(7) events will
block only until a service is running or until a task has finished.
respawn
A service or task with this stanza will be automatically started
if it should stop abnormally. All reasons for a service
stopping, except the stop(8) command itself, are considered
abnormal. Tasks may exit with a zero exit status to prevent
being respawned.
respawn limit COUNT INTERVAL
Respawning is subject to a limit, if the job is respawned more
than COUNT times in INTERVAL seconds, it will be considered to
be having deeper problems and will be stopped. Default COUNT is
10. Default INTERVAL is 5 seconds.
This only applies to automatic respawns and not the restart(8)
command.
normal exit STATUS|SIGNAL...
Additional exit statuses or even signals may be added, if the
job process terminates with any of these it will not be
considered to have failed and will not be respawned.
normal exit 0 1 TERM HUP
Instances
By default, only one instance of any job is permitted to exist at one
time. Attempting to start a job when it's already starting or running
results in an error. Note that a job is considered to be running if its
pre-start process is running.
Multiple instances may be permitted by defining the names of those
instances. If an instance with the same name is not already starting
or running, a new instance will be started instead of returning an
error.
instance NAME
This stanza defines the names of instances, on its own its not
particularly useful since it would just define the name of the
single permitted instance, however NAME expands any variable
defined in the job's environment.
These will often be variables that you need to pass to the
process anyway, so are an excellent way to limit the instances.
instance $CONFFILE
exec /sbin/httpd -c $CONFFILE
instance $TTY
exec /sbin/getty -8 38300 $TTY
These jobs appear in the initctl(8) output with the instance
name in parentheses, and have the INSTANCE environment variable
set in their events.
Documentation
Upstart provides several stanzas useful for documentation and external
tools.
description DESCRIPTION
This stanza may contain a description of the job.
description "This does neat stuff"
author AUTHOR
This stanza may contain the author of the job, often used as a
contact for bug reports.
author "Scott James Remnant <scott@netsplit.com>"
version VERSION
This stanza may contain version information about the job, such
as revision control or package version number. It is not used
or interpreted by init(8) in any way.
version "$Id$"
emits EVENT...
All processes on the system are free to emit their own events by
using the initctl(8) tool, or by communicating directly with the
init(8) daemon.
This stanza allows a job to document in its job configuration
what events it emits itself, and may be useful for graphing
possible transitions.
The initctl(8) check-config command attempts to use this stanza
to resolve events.
EVENT can be either a literal string or a string including shell
wildcard meta-characters (asterisk ('*'), question mark ('?'),
and square brackets ('[' and ']')). Meta-characters are useful
to allow initctl(8) check-config to resolve a class of events,
such as those emitted by upstart-udev-bridge(8).
usage USAGE
This stanza may contain the text used by initctl(8) usage
command. This text may be also shown when commands start(8),
stop(8) or status(8) fail.
usage "tty DEV=ttyX - where X is console id"
Process environment
Many common adjustments to the process environment, such as resource
limits, may be configured directly in the job rather than having to
handle them yourself.
console none|log|output|owner
none
If none is specified, the jobs standard input, standard
output and standard error file descriptors are connected
to /dev/null. Any output generated by a job will be
discarded. This used to be the default prior to the
introduction of log in Upstart 1.4.
log
Only applies to system jobs: if specified by user jobs,
the job will be considered to have specified the value
none.
For system jobs, if log is specified, standard input is
connected to /dev/null, and standard output and standard
error are connected to a pseudo-tty which logs all job
output.
Output is logged to file /var/log/upstart/<job-log-file>.
If a job has specified instance, <job-log-file> will
equate to <job>-<instance>.log where '<instance>' is
replaced by the specific instance value and '<job>' is
replaced with the job name (job configuration file name,
without the extension). If instance is not specified,
<job-log-file> will be <job>.log where '<job>' is
replaced with the job name.
If log files already exist, they are appended to.
All slash ('/') characters in <job-log-file> are replaced
with underscore ('_') characters. For example, any output
from the 'wibble' instance of the 'foo/bar' job would be
encoded in file 'foo_bar-wibble.log' in the log file
directory. This gives the log file directory a flat
structure.
If the directory for system jobs does not exist, job
output for each job will be cached until the job
finishes. Thus, the boot process must ensure that the
directory is available as soon as possible since any job
that finishes before a writeable disk is available will
not be able to take advantage of this facility.
If it is not possible to write to any log file due to
lack of disk space, the job will be considered to have
specified a console value of none and all subsequent job
output will be discarded.
If the logger detects that the file it is about to write
to was deleted, it will re-open the file first.
Care should be taken if the log directory is a mount
point since any job that starts before that mount is
available and which produces output will then attempt to
write logs to the mount point, not to the mounted
directory. This may give the impression that log data has
not been recorded. A strategy to handle this situation is
to ensure the mount point directory is not writeable such
that logs will only be written when the mount has
succeeded (assuming the mount itself is writeable and has
sufficient space).
Note that since log utilizes pseudo-ttys, your kernel
must support these. If it does not, the console value
will be modified automatically to none. Further, note
that it may be necessary to increase the number of
available pty devices; see pty(7) for details.
Under Linux, full Unix 98 pty support requires that the
devpts filesystem be mounted.
If pty setup fails for any reason, an error message will
be displayed and the job's console value will be reset to
none.
output
If output is specified, the standard input, standard
output and standard error file descriptors are connected
to /dev/console.
owner
The owner value is special: it not only connects the job
to the system console but sets the job to be the owner of
the system console, which means it will receive certain
signals from the kernel when special key combinations
such as Control-C are pressed.
umask UMASK
A common configuration is to set the file mode creation mask for
the process. UMASK should be an octal value for the mask, see
umask(2) for more details.
nice NICE
Another common configuration is to adjust the process's nice
value, see nice(1) for more details.
oom score ADJUSTMENT|never
Normally the OOM killer regards all processes equally, this
stanza advises the kernel to treat this job differently.
ADJUSTMENT may be an integer value from -999 (very unlikely to
be killed by the OOM killer) up to 1000 (very likely to be
killed by the OOM killer). It may also be the special value
never to have the job ignored by the OOM killer entirely.
chroot DIR
Runs the job's processes in a chroot(8) environment underneath
DIR
Note that DIR must have all the necessary system libraries for
the process to be run, often including /bin/sh
chdir DIR
Runs the job's processes with a working directory of DIR instead
of the root of the filesystem.
limit LIMIT SOFT|unlimited HARD|unlimited
Sets initial system resource limits for the job's processes.
LIMIT may be one of core, cpu, data, fsize, memlock, msgqueue,
nice, nofile, nproc, rss, rtprio, sigpending or stack.
Limits are specified as both a SOFT value and a HARD value, both
of which are integers. The special value unlimited may be
specified for either.
setuid USERNAME
Changes to the user USERNAME before running any job process.
If this stanza is unspecified, all job processes will run as
root in the case of system jobs, and as the user in the case of
user jobs.
Note that system jobs using the setuid stanza are still system
jobs, and can not be controlled by an unprivileged user, even if
the setuid stanza specifies that user.
setgid GROUPNAME
Changes to the group GROUPNAME before running any job process.
If this stanza is unspecified, the primary group of the user
specified in the setuid block is used for all job processes. If
both stanzas are unspecified, all job processes will run with
its group ID set to 0 in the case of system jobs, and as the
primary group of the user in the case of User Jobs.
Override File Handling
Override files allow a jobs environment to be changed without modifying
the jobs configuration file. Rules governing override files:
o If a job is embodied with only a configuration file, the contents of
this file define the job.
o If an override files exists where there is no existing cofiguration
file, the override file is ignored.
o If both a configuration file and an override file exist for a job and
both files are syntactically correct:
o stanzas in the override file will take precedence over stanzas
present in the corresponding configuration file.
o stanzas in the override file which are not present in the
corresponding configuration file will be honoured when the job
runs.
o If both a configuration file and an override file exist for a job and
subsequently the override file is deleted, the configuration file is
automatically reloaded with the effect that any changes introduced by
the override file are undone and the configuration file alone now
defines the job.
o If both a configuration file and an override file exist for a job and
subsequently the configuration file is deleted, a new instance of the
job can no longer be started (since without a corresponding
configuration file an override file is ignored).
o If both a configuration file and an override file exist for a job and
any of the contents of the override file are invalid, the override
file is ignored and only the contents of the configuration file are
considered.
Miscellaneous
kill signal SIGNAL
Specifies the stopping signal, SIGTERM by default, a job's main
process will receive when stopping the running job.
kill signal INT
kill timeout INTERVAL
Specifies the interval between sending the job's main process
the "stopping" (see above) and SIGKILL signals when stopping the
running job. Default is 5 seconds.
expect stop
Specifies that the job's main process will raise the SIGSTOP
signal to indicate that it is ready. init(8) will wait for this
signal before running the job's post-start script, or
considering the job to be running.
init(8) will send the process the SIGCONT signal to allow it to
continue.
expect daemon
Specifies that the job's main process is a daemon, and will fork
twice after being run. init(8) will follow this daemonisation,
and will wait for this to occur before running the job's
post-start script or considering the job to be running.
Without this stanza init(8) is unable to supervise daemon
processes and will believe them to have stopped as soon as they
daemonise on startup.
expect fork
Specifies that the job's main process will fork once after being
run. init(8) will follow this fork, and will wait for this to
occur before running the job's post-start script or considering
the job to be running.
Without this stanza init(8) is unable to supervise forking
processes and will believe them to have stopped as soon as they
fork on startup.
RESTRICTIONS
The use of symbolic links in job configuration file directories is not
supported since it can lead to unpredicable behaviour resulting from
broken or inaccessible links (such as would be caused by a link
crossing a filesystem boundary to a filesystem that has not yet been
mounted).
BUGS
The and and or operators allowed with start on and stop on do not work
intuitively: operands to the right of either operator are only
evaluated once and state information is then discarded. This can lead
to jobs with complex start on or stop on conditions not behaving as
expected when restarted. For example, if a job encodes the following
condition:
start on A and (B or C)
When 'A' and 'B' become true, the condition is satisfied so the job
will be run. However, if the job ends and subsequently 'A' and 'C'
become true, the job will not be re-run even though the condtion is
satisfied. Avoid using complex conditions with jobs which need to be
restarted.
FILES
/etc/init/*.conf
System job configuration files.
/etc/init/*.override
System job override files.
$HOME/.init/*.conf
User job configuration files. Note that you may make the
directory $HOME/.init/ a symbolic link to
$HOME/.config/upstart/.
$HOME/.init/*.override
User job override files.
/var/log/upstart/*.log
Default location of system job output logs.
AUTHOR
Manual page written by Scott James Remnant <scott@netsplit.com> and
James Hunt <james.hunt@canonical.com>.
REPORTING BUGS
Report bugs at <https://launchpad.net/upstart/+bugs>
COPYRIGHT
Copyright (C) 2009-2011 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
init(8) initctl(8) sh(1) upstart-events(7) pty(7)