Red Hat ENTERPRISE LINUX 5 - VIRTUAL SERVER ADMINISTRATION, Руководство по установке

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Chapter 33. Boot Process, Init, and Shutdown
360
For more information on single-user and rescue mode, refer to the chapter titled
Basic
System Recovery
in the
Red Hat Enterprise Linux Deployment Guide
.
It is possible to change the default runlevel at boot time by modifying the arguments passed by the
boot loader to the kernel. For information on changing the runlevel at boot time, refer to
Section 9.8,
“Changing Runlevels at Boot Time”
.
33.4.2. Runlevel Utilities
One of the best ways to configure runlevels is to use an
initscript utility
. These tools are designed
to simplify the task of maintaining files in the SysV init directory hierarchy and relieves system
administrators from having to directly manipulate the numerous symbolic links in the subdirectories of
/etc/rc.d/
.
Red Hat Enterprise Linux provides three such utilities:
•
/sbin/chkconfig
— The
/sbin/chkconfig
utility is a simple command line tool for maintaining
the
/etc/rc.d/init.d/
directory hierarchy.
•
/usr/sbin/ntsysv
— The ncurses-based
/sbin/ntsysv
utility provides an interactive text-based
interface, which some find easier to use than
chkconfig
.
•
Services Configuration Tool
— The graphical
Services Configuration Tool
(
system-config-
services
) program is a flexible utility for configuring runlevels.
Refer to the chapter titled
Controlling Access to Services
in the
Red Hat Enterprise Linux Deployment
Guide
for more information regarding these tools.
33.5. Shutting Down
To shut down Red Hat Enterprise Linux, the root user may issue the
/sbin/shutdown
command.
The
shutdown
man page has a complete list of options, but the two most common uses are:
/sbin/shutdown --h now
and
/sbin/shutdown --r now
After shutting everything down, the
-h
option halts the machine, and the
-r
option reboots.
PAM console users can use the
reboot
and
halt
commands to shut down the system while in
runlevels 1 through 5. For more information about PAM console users, refer to the Red Hat Enterprise
Linux Deployment Guide.
If the computer does not power itself down, be careful not to turn off the computer until a message
appears indicating that the system is halted.
Failure to wait for this message can mean that not all the hard drive partitions are unmounted, which
can lead to file system corruption.