shutdown - Shuts down a single system or an entire cluster
/usr/sbin/shutdown [-bfhknrs] time [warning-message...]
/usr/sbin/shutdown -c [-h | -hs] time [warning-message...]
Sends a shutdown message to the rwalld daemon on all
remote client hosts that have NFS file systems mounted
from this system. This option is incompatible with the -c
option. Shuts down and halts all members of a cluster in
an orderly fashion. The -h and -s options are invoked by
default when the -c option is specified alone. That is,
there is no difference between specifying the -c option
alone and specifying -csh. If any options other than -h
and -s are specified with the -c option, the shutdown command
displays a usage message and exits. Performs a fast
shutdown (in the manner of the fastboot and the fasthalt
programs), bypassing the messages to other users and
bringing the system down as quickly as possible. The system
halts or reboots without checking the file systems.
For example, the shutdown -f time command brings the system
to single user and creates the /fastboot file; when
the system reboots to multiuser, it does not invoke fsck.
The shutdown -f -r time command shuts the system down,
creates the /fastboot file, then immediately reboots. The
shutdown -f -h time command creates the /fastboot file and
halts the system.
The -f option is incompatible with the -c and -n
options. Causes the system or cluster to shut down
and halt.
When shutting down a single system, the shutdown
command sends a SIGTERM signal to the init process,
which brings it to single-user mode, and then
issues a halt command. However, if the -s option
is specified with the -h option, the shutdown command
executes the run-level transition scripts (and
does not send the SIGTERM signal) before halting
the system.
Because halt is the only option when shutting down
an entire cluster, the -h option is invoked by
default when the -c option is specified alone.
Sends shutdown messages to users, warning them of
an impending shutdown. However, the system does not
actually shut down. The /etc/nologin_hostname file
is not created.
This option is incompatible with the -c option.
Bypasses the normal synchronization (syncing) of
disks before stopping the system.
The -n option is incompatible with the -f and -c
options. Causes the system to shut down and
reboot.
The shutdown command accomplishes this by sending a
SIGTERM signal to the init process, which brings it
to single-user mode, and then issues the reboot
command. However, if the -s option is specified
with the -r option, the shutdown command executes
the run-level transition scripts (and does not send
the SIGTERM signal) before rebooting the system.
This option is incompatible with the -c option.
Executes the stop entry point of the run-level
transition scripts in /sbin/rc0.d/Knn_name,
/sbin/rc2.d/Knn_name, and /sbin/rc3.d/Knn_name (for
example, the stop entry point of
/sbin/rc0.d/K45syslog).
The run level at which the shutdown command is
invoked determines which scripts are executed. If
the current run level is level 3 or higher, the
Knn_name scripts from all three directories are
run. If the run level is 2, then only scripts from
/sbin/rc0.d and /sbin/rc2.d are run. If the run
level is 1, only scripts from /sbin/rc0.d are run.
This option is default for single-system shutdowns
and optional for clusterwide shutdowns. But it is
invoked by default for clusterwide shutdowns, if
the -c option is specified alone. It can be used
only with the -r, -c, or -h options.
Defines the time at which the shutdown command will shut
down the system (or cluster when the -c option is specified).
There are several ways to express this time: Use
the word now to cause an immediate shutdown. Specify a
future time using the format: +number. This format starts
a shutdown in number minutes. Specify a future time using
the format: hhmm. This format starts a shutdown at the
indicated time. You can separate the hours (hh) and minutes
(mm) with a colon (:). Anything following the time
operand on the command line is considered to be a message,
which is broadcast to users currently logged into the system
or cluster. Prior to shutdown, the message is displayed
on all user terminals. The message is sent more
frequently as the shutdown time approaches.
The shutdown command provides an automated shutdown procedure.
You must be root to use this command.
When shutting down a single system, use the shutdown command
shown in the first format line in the SYNOPSIS section.
If the -s option is not specified, the shutdown command
sends a SIGTERM signal to the init process, which
shuts the system down to single-user mode. It then halts
the system, reboots it, or does nothing, depending upon
whether the -h, -r, or neither option is specified: If the
-h option is specified, the system is shut down to singleuser
mode and then halted. If the -r option is specified,
the system is shut down to single-user mode and rebooted.
If neither the -h or -r options is specified, the system
is shut down to and remains in single-user mode.
If you specify the -s option with the -h or -r option, the
shutdown command does not send the SIGTERM signal prior to
halting or rebooting the system. Rather, it executes the
stop entry point of the run level transition scripts in
/sbin/rc0.d/Knn_name, /sbin/rc2.d/Knn_name, and
/sbin/rc3.d/Knn_name. The run level at which the shutdown
command is invoked determines which scripts are executed.
When shutting down an entire cluster, use the shutdown
command shown in the second format line in the SYNOPSIS
section:
/usr/sbin/shutdown -c [-h | -hs] time [warning-message...]
You must shut an entire cluster down to a halt. Automatic
reboots and shutting down to single-user mode are not supported.
(If you want to bring a cluster member to singleuser
mode, first shut down that member to a halt and then
boot it to single-user mode.)
If you specify only the -c option, the -h and -s options
are invoked by default. If you specify both the -c and -h
options, the cluster halts without executing the stop
entry point of the run-level transition scripts.
The shutdown process is similar for single-system and
cluster shutdowns. Five minutes before shutdown (or immediately,
if shutdown is in fewer than five minutes) the
shutdown command creates the /etc/nologin_hostname file
(or /etc/nologin in the case of a clusterwide shutdown)
and copies the warning-message and time of the shutdown to
it. If a user subsequently attempts to log in, the login
program checks for the existence of /etc/nologin_hostname
or /etc/nologin as appropriate, prints the contents, and
exits. The shutdown command removes the /etc/nologin_hostname
or /etc/nologin file just before it exits.
Similarly, when the shutdown command is invoked with the
-c option to shut down an entire cluster, the shutdown
command creates the /cluster/admin/.clu_shutdown_file file
and copies the shutdown parameters to it. The existence of
this file prevents new members from joining a cluster
while a clusterwide shutdown is in progress. (This means
that you must never reboot a cluster member before all
cluster members have been shut down to a halt and are
resting at the console boot prompt.) It also prevents multiple
clusterwide shutdowns from occurring simultaneously.
The time operand establishes a "grace period" during which
you can cancel a shutdown. You must not abort a shutdown
process after the grace period ends and the shutdown actually
begins.
To cancel a system or cluster shutdown during the grace
period, use the following procedure: From the system on
which you executed the shutdown command, identify the
shutdown processes. There is a single shutdown process
for /usr/sbin/shutdown; in a cluster, there may also be a
/usr/sbin/clu_shutdown process. For example: # ps ax |
grep -v grep | grep shutdown 14680 ttyp5 I <
0:00.01 /usr/sbin/shutdown +20 going down 14687 ttyp5 I
< 0:00.01 /usr/sbin/clu_shutdown Terminate all of
them by specifying their PIDs in a kill command. For example:
# kill 14680 14687
If you kill the shutdown processes during the grace
period, the shutdown is canceled and the /etc/nologin_hostname
file is removed. In a clusterwide shutdown,
the /etc/nologin and /cluster/admin/.clu_shutdown_file
files are removed.
Caution
If a clusterwide shutdown does not run to completion, the
remaining members could be left in a state with quorum
checking turned off. Logins, member boots, and additional
clusterwide shutdowns could all be disabled. To clear
this state, you must manually shut down the remaining members
one at a time (for example, by using the shutdown -h
command) before resuming cluster operation. Failure to
do so can lead to unpredictable cluster operation and possible
data corruption. In the rare event that a member
does not respond to the shutdown -h command, use the
/usr/sbin/halt command to halt it. If you must halt multiple
members in this manner, halt them one at a time. As
a final resort, press the member's halt button to halt it
and then crash the system at the console prompt to create
a crash dump.
At shutdown time, the shutdown command writes a message to
the system log. This message states the time of the shutdown,
who ran the shutdown command, and the reason.
You can only use the -h and -s options with the -c option,
but they are invoked by default when you use the -c option
alone. There is no difference if you use the shutdown command
with the -c option or with the -chs options.
You cannot use the -f option with the -n option.
You can only use the -s option with the -c, -h, or -r
options.
Specifies the command path. Location of the nologin file
for a clusterwide shutdown. Location of the nologin file
for a nonclustered system. For example, /etc/nologin_sys5.sys.site.com.
Contains parameters associated
with a clusterwide shutdown. This file is locked during a
clusterwide shutdown to prevent multiple simultaneous
clusterwide shutdowns and to keep new members from joining
the cluster during the shutdown. A record of all clusterwide
shutdowns for the cluster is written to this file.
Clusterwide shutdown script called by the shutdown command.
Commands: login(1), wall(1), fastboot(8), fasthalt(8),
halt(8), reboot(8)
shutdown(8)
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