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shutdown(8)
NAME
shutdown - Shuts down a single system or an entire cluster
SYNOPSIS
/usr/sbin/shutdown [-bfhknrs] time [warning-message ...]
/usr/sbin/shutdown -c [-hs] time [warning-message ...]
PARAMETERS
time 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 (:).
warning-message
Anything following the time parameter 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.
OPTIONS
-b 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.
-c 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. 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.
-f 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 option.
-h 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. Additionally, executing the run-level scripts is
mandatory in a clusterwide shutdown, thus the -s option is
invoked by default, too.
-k 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.
-n Bypasses the normal synchronization (syncing) of disks before
stopping the system.
The -n option is incompatible with the -f and -c options.
-r 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 -h 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.
-s 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 optional for single-system shutdowns but is
invoked by default for clusterwide shutdowns. It can be used only
with the -r, -c, or -h options.
DESCRIPTION
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 single-user
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 [-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 specify the -c
option, the -h and -s options are invoked by default.
The shutdown process is similar for single-system and cluster shutdowns.
Five minutes before shutdown (or immediately, if shutdown is in less 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 command parameters to
it. The existence of this file prevents new members from joining a cluster
while a clusterwide shutdown is in progress. It also prevents multiple
clusterwide shutdowns from occurring simultaneously.
The time parameter establishes a "grace period" during which you can cancel
a shutdown. You must not abort a shutdown process once the grace period
ends and the shutdown actually begins.
To cancel a system or cluster shutdown during the grace period, use the
following procedure:
1. 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
2. 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.
Warning
If a clusterwide shutdown does not run to completion, the remaining
members might be left in a state with quorum checking turned off.
Logins, member boots, and additional clusterwide shutdowns might 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.
FILES
/usr/sbin/shutdown
Specifies the command path.
/etc/nologin
Location of the nologin file for a clusterwide shutdown.
/etc/nologin_hostname
Location of the nologin file for a nonclustered system. For
example, /etc/nologin_sys5.zk3.dec.com.
/cluster/admin/.clu_shutdown_file
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.
/cluster/admin/.clu_shutdown_log
A record of all clusterwide shutdowns for the cluster is written
to this file.
/usr/sbin/clu_shutdown
Clusterwide shutdown script called by the shutdown command.
RELATED INFORMATION
Commands: fastboot(8), fasthalt(8), halt(8), login(1), reboot(8), wall(1)
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