Chapter 8 Run Levels and Boot Files (Tasks)
This chapter provides guidelines for shutting down and booting a system
and information about run levels and boot files.
This is a list of the step-by-step instructions in this chapter.
This is a list of overview information in this chapter.
Run Levels
A system's run level (also known as an init state)
defines what services and resources are available to users. A system can be
in only one run level at a time.
The Solaris environment has eight run levels, which are described in
the following table. The default run level is specified in the /etc/inittab file as run level 3.
Table 8-1 Solaris Run Levels
|
Run Level
|
Init State
|
Type
|
Use This Level ...
|
|
0
|
Power-down state
|
Power-down
|
To shut down the operating system so that it is safe to turn off power to
the system.
|
|
s or S
|
Single-user
state
|
Single-user
|
To run as a single user with all file systems mounted and accessible.
|
|
1
|
Administrative state
|
Single-user
|
To access all available file systems with user logins allowed.
|
|
2
|
Multiuser state
|
Multiuser
|
For normal
operations. Multiple users can access the system and the entire file system.
All daemons are running except for the NFS server daemons.
|
|
3
|
Multiuser state with NFS resources shared
|
Multiuser
|
For normal operations with NFS resource-sharing available.
|
|
4
|
Alternative multiuser state
|
|
This level is currently unavailable.
|
|
5
|
Power-down state
|
Power-down
|
To shut down
the operating system so that it is safe to turn off power to the system. If
possible, automatically turn off power on systems that support this feature.
|
|
6
|
Reboot state
|
Reboot
|
To shut down the
system to run level 0, and then reboot to multiuser state (or whatever level
is the default in the inittab file).
|
How to Determine a System's Run Level
Display run level information by using the who -r
command to determine a system's run level.
Use the who -r command to determine a system's current
run level for any level except run level 0.
Example--Determining a System's Run Level
$ who -r
. run-level 3 Sep 1 14:45 3 0 S
$
|
|
run level 3
|
Identifies the current run level.
|
|
Sep 1 14:45
|
Identifies the date of last run level
change.
|
|
3
|
Is the current run level.
|
|
0
|
Identifies the number of times at this
run level since the last reboot.
|
|
S
|
Identifies the previous run level.
|
The /etc/inittab File
When you boot the system or change run levels with the init or shutdown command, the init
daemon starts processes by reading information from the /etc/inittab file. This file defines three important items for the init process:
-
The system's default run level
-
What processes to start, monitor, and restart if
they terminate
-
What actions to be taken when the system enters
a new run level
Each entry in the /etc/inittab file has the following
fields:
id:rstate:action:process
The following table describes the fields in an inittab
entry.
Table 8-2 Fields in the
inittab File
|
Field
|
Description
|
|
id
|
A unique identifier for the entry.
|
|
rstate
|
A list of run levels to which this
entry applies.
|
|
action
|
How the process specified in the process
field is to be run. Possible values include: initdefault, sysinit, boot, bootwait, wait, and respawn.
|
|
process
|
The command to execute.
|
Example--Default inittab File
The following example shows an annotated default inittab
file:
1 ap::sysinit:/sbin/autopush -f /etc/iu.ap
2 ap::sysinit:/sbin/soconfig -f /etc/sock2path
3 fs::sysinit:/sbin/rcS sysinit >/dev/msglog 2<>/dev/msglog </dev/console
4 is:3:initdefault:
5 p3:s1234:powerfail:/usr/sbin/shutdown -y -i5 -g0 >/dev/msglog 2<>/dev/...
6 sS:s:wait:/sbin/rcS >/dev/msglog 2<>/dev/msglog </dev/console
7 s0:0:wait:/sbin/rc0 >/dev/msglog 2<>/dev/msglog </dev/console
8 s1:1:respawn:/sbin/rc1 >/dev/msglog 2<>/dev/msglog </dev/console
9 s2:23:wait:/sbin/rc2 >/dev/msglog 2<>/dev/msglog </dev/console
10 s3:3:wait:/sbin/rc3 >/dev/msglog 2<>/dev/msglog </dev/console
11 s5:5:wait:/sbin/rc5 >/dev/msglog 2<>/dev/msglog </dev/console
12 s6:6:wait:/sbin/rc6 >/dev/msglog 2<>/dev/msglog </dev/console
13 fw:0:wait:/sbin/uadmin 2 0 >/dev/msglog 2<>/dev/msglog </dev/console
14 of:5:wait:/sbin/uadmin 2 6 >/dev/msglog 2<>/dev/msglog </dev/console
15 rb:6:wait:/sbin/uadmin 2 1 >/dev/msglog 2<>/dev/msglog </dev/console
16 sc:234:respawn:/usr/lib/saf/sac -t 300
17 co:234:respawn:/usr/lib/saf/ttymon -g -h -p "`uname -n` console login: "
-T terminal-type -d /dev/console -l console -m ldterm,ttcompat
|
-
Initializes STREAMS modules
-
Configures socket transport providers
-
Initializes file systems
-
Defines default run level
-
Describes a power fail shutdown
-
Defines single-user mode
-
Defines run level 0
-
Defines run level 1
-
Defines run level 2
-
Defines run level 3
-
Defines run level 5
-
Defines run level 6
-
Defines an unused level, firmware
-
Defines an unused level, off
-
Defines an unused level, reboot
-
Initializes Service Access Controller
-
Initializes console
What Happens When the System Is Brought to Run Level 3
-
The init process is started and reads the /etc/default/init file to set any environment variables. By default,
only the TIMEZONE variable is set.
-
Then init reads the inittab file to do the following:
-
Identify the initdefault entry, which defines
the default run level (3).
-
Execute any process entries that have sysinit in the action field so that any special initializations
can take place before users login.
-
Execute any process entries that have 3 in the rstate field, which matches the default run level, 3.
See init(1M)
for a detailed description of how the init process uses
the inittab file.
The following table describes the key words used for run level 3's action
field.
Table 8-3 Run Level 3 Action Key Word Descriptions
|
Key Word
|
Starts the Specified Process ...
|
|
powerfail
|
Only when the system receives a
power fail signal.
|
|
wait
|
And waits for its termination.
|
|
respawn
|
If it does not exist. If the process
already exists, continue scanning the inittab file.
|
The following table describes the processes (or commands) executed at
run level 3.
Table 8-4 Run Level 3 Command Descriptions
|
Command or Script
Name
|
Description
|
|
/usr/sbin/shutdown
|
Shuts down the system. The init process runs the shutdown command only if
the system has received a powerfail signal.
|
|
/sbin/rcS
|
Mounts and checks root (/), /usr, /var, and /var/adm file systems.
|
|
/sbin/rc2
|
Starts the standard system processes,
bringing the system up into run level 2 (multiuser mode).
|
|
/sbin/rc3
|
Starts NFS resource sharing for run
level 3.
|
|
/usr/lib/saf/sac -t 30
|
Starts the
port monitors and network access for UUCP. This process is restarted if it
fails.
|
|
/usr/lib/saf/ttymon -g
-h -p "`uname -n` console login: " -T terminal_type -d /dev/console -l console
|
Starts the ttymon
process that monitors the console for login requests. This process is restarted
if it fails.
The terminal_type on a
SPARC based system is sun
The terminal_type on an IA based system is AT386
|
Run Control Scripts
The Solaris software environment provides a detailed series of run control
(rc) scripts to control run level changes. Each run level
has an associated rc script located in the /sbin directory:
-
rc0
-
rc1
-
rc2
-
rc3
-
rc5
-
rc6
-
rcS
For each rc script in the /sbin
directory, there is a corresponding directory named /etc/rcn.d that contains scripts to perform various
actions for that run level. For example, /etc/rc2.d contains
files used to start and stop processes for run level 2.
# ls /etc/rc2.d
K07dmi S70uucp S75cron S91afbinit
K07snmpdx S71ldap.client S75flashprom S91ifbinit
K28nfs.server S71rpc S75savecore S92volmgt
README S71sysid.sys S76nscd S93cacheos.finish
S01MOUNTFSYS S72autoinstall S80PRESERVE S94ncalogd
S05RMTMPFILES S72inetsvc S80lp S95IIim
S20sysetup S72slpd S80spc S95amiserv
S21perf S73cachefs.daemon S85power S95ocfserv
S30sysid.net S73nfs.client S88sendmail S99audit
S40llc2 S74autofs S88utmpd S99dtlogin
S47asppp S74syslog S89bdconfig
S69inet S74xntpd S90wbem
|
The /etc/rcn.d scripts are always run in ASCII sort order. The scripts have
names of the form:
[KS][0-9][0-9]*
Files beginning with K are run to terminate (kill)
a system process. Files beginning with S are run to start
a system process.
Run control scripts are also located in the /etc/init.d
directory. These files are linked to corresponding run control scripts in
the /etc/rcn.d
directories.
The actions of each run control script are summarized in Table 8-5.
Using a Run Control Script to Stop or Start Services
One advantage of having individual scripts for each run level is that
you can run scripts in the /etc/init.d directory individually
to turn off functionality without changing a system's run level.
How to Use a Run Control Script to Stop or Start a Service
-
Become superuser.
-
Turn off functionality.
# /etc/init.d/filename stop
|
-
Restart functionality.
# /etc/init.d/filename start
|
-
Use the pgrep command to verify whether the service
has been stopped or started.
Example--Using a Run Control Script to Stop or Start a Service
Turn off NFS server functionality by typing:
# /etc/init.d/nfs.server stop
# pgrep -f nfs
#
|
Restart the NFS services by typing:
# /etc/init.d/nfs.server start
# pgrep -f nfs
141
143
245
247
# pgrep -f nfs -d, | xargs ps -fp
daemon 141 1 40 Jul 31 ? 0:00 /usr/lib/nfs/statd
root 143 1 80 Jul 31 ? 0:01 /usr/lib/nfs/lockd
root 245 1 34 Jul 31 ? 0:00 /usr/lib/nfs/nfsd -a 16
root 247 1 80 Jul 31 ? 0:02 /usr/lib/nfs/mountd
|
Adding a Run Control Script
If you want to add a run control script to start and stop a service,
copy the script into the /etc/init.d directory and create
links in the rcn.d directory you want the service to start and stop.
See the README file in each /etc/rcn.d directory for more information on naming
run control scripts. The procedure below describes how to add a run control
script.
How to Add a Run Control Script
-
Become superuser.
-
Add the script to the /etc/init.d directory.
# cp filename /etc/init.d
# chmod 0744 /etc/init.d/filename
# chown root:sys /etc/init.d/filename
|
-
Create links to the appropriate rcn.d directory.
# cd /etc/init.d
# ln filename /etc/rc2.d/Snnfilename
# ln filename /etc/rcn.d/Knnfilename
|
-
Use the ls command to verify that the script has
links in the specified directories.
# ls /etc/init.d/ /etc/rc2.d/ /etc/rcn.d/
|
Example--Adding a Run Control Script
# cp xyz /etc/init.d
# cd /etc/init.d
# ln xyz /etc/rc2.d/S100xyz
# ln xyz /etc/rc0.d/K100xyz
# ls /etc/init.d /etc/rc2.d /etc/rc0.d
|
Disabling a Run Control Script
Disable a run control script by renaming it with a dot (.) at the beginning of the new file name. Files that begin with
a dot are not executed. If you copy a file by adding a suffix to it, both
files will be run.
How to Disable a Run Control Script
-
Become superuser.
-
Rename the script by adding an underscore (_) to the beginning of the
new file.
# cd /etc/rcn.d
# mv filename _filename
|
-
Verify the script has been renamed.
Example--Disabling a Run Control Script
The following example changes the S100datainit
script name but saves the original script.
# cd /etc/rc2.d
# mv S100datainit _S100datainit
|
Run Control Script Summaries
Table 8-5 The
/sbin/rc0 Script
|
Script Name
|
Description
|
|
/sbin/rc0
|
Performs
the following tasks:
|
|
|
-
Stops system services and daemons
-
Terminates all running processes
-
Unmounts all file systems
|
Table 8-6 The
/sbin/rc1 Script
|
Script Name
|
Description
|
|
/sbin/rc1
|
Runs the /etc/rc1.d scripts to perform the following tasks:
|
|
|
-
Stops system services and daemons
-
Terminates all running processes
-
Unmounts all file systems
-
Brings the system up in single-user mode
|
Table 8-7 The
/sbin/rc2 Script
|
Script Name
|
Description
|
|
/sbin/rc2
|
Runs the /etc/rc2.d scripts to perform the following tasks:
|
|
-
Mounts all local file systems
-
Enables disk quotas if at least one file system
was mounted with the quota option
-
Saves editor temporary files in /usr/preserve
-
Removes any files in the /tmp
directory
-
Configures system accounting
-
Configures default router
-
Sets NIS domain and ifconfig
netmask
-
Reboots the system from the installation media
or a boot server if either /.PREINSTALL or /AUTOINSTALL exists
-
Starts inetd and rpcbind and named, if appropriate
-
Starts Kerberos client-side daemon, kerbd
-
Starts NIS daemons (ypbind)
and NIS+ daemons (rpc.nisd), depending on whether the system
is configured for NIS or NIS+, and whether the system is a client or a server
-
Starts keyserv, statd, lockd, xntpd, and utmpd
-
Mounts all NFS entries
-
Starts nscd (name service cache
daemon)
-
Starts automount, cron, LP print service, sendmail, utmpd, and vold daemons
|
Note -
Many of the system services and applications that are started at run
level 2 depend on what software is installed on the system.
Table 8-8 The
/sbin/rc3 Script
|
Script Name
|
Description
|
|
/sbin/rc3
|
Runs the /etc/rc3.d scripts to perform the following tasks:
|
|
-
Cleans up sharetab
-
Starts nfsd
-
Starts mountd
-
If the system is a boot server, starts rarpd, rpc.bootparamd, and rpld
-
Starts snmpdx (Solstice Enterprise
AgentsTM process).
|
Table 8-9 The
/sbin/rc5 and
/sbin/rc6
Scripts
|
Script Name
|
Description
|
|
/sbin/rc5
and /sbin/rc6
|
Runs the /etc/rc0.d/K* scripts to perform the following
tasks:
|
|
|
| |
Table 8-10 The
/sbin/rcS Script
|
Script Name
|
Description
|
|
/sbin/rcS
|
Runs the /etc/rcS.d scripts to bring the system up to run level S. The following
tasks are performed from these scripts:
|
|
-
Establishes a minimal network
-
Mounts /usr, if necessary
-
Sets the system name
-
Checks the root (/) and /usr file systems
-
Mounts pseudo file systems (/proc
and /dev/fd)
-
Rebuilds the device entries for reconfiguration
boots
-
Checks and mounts other file systems to be mounted
in single-user mode
|
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