Chapter 11Run Levels and Boot Files (Tasks)
This chapter provides overview information and tasks that
are related to run levels and boot files.
This is a list of the step-by-step instructions in this chapter.
This is a list of the 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 11-1 Solaris Run Levels
Run Level | Init State | Type | Purpose |
|---|
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 some file systems mounted and accessible. |
1 | Administrative state | Single-user | To access all available file systems. User logins are disabled. |
2 | Multiuser state | Multiuser | For normal
operations. Multiple users can access the system and all file system. All
daemons are running except for the NFS server daemons. |
3 | Multiuser level with NFS resources shared | Multiuser | For normal operations with NFS resources shared. This is
the default run level for the Solaris environment. |
4 | Alternative multiuser state | | 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 turns 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 level with NFS resources
shared (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.
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
This example displays information a system's current run level and information
about previous run levels.
$ who -r
. run-level 31 Dec 13 10:102 33 04 S5
$
|
Identifies the current run level
Identifies the date of last run level change
Also identifies the current run level
Identifies the number of times the system has been at this
run level since the last reboot
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 take 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 11-2 Fields Descriptions for the inittab File
Field | Description |
|---|
id | Is a unique identifier for the entry. |
rstate | Lists the run levels to which this
entry applies. |
action | Identifies how the process that is
specified in the process field is to be run. Possible values include: initdefault, sysinit, boot, bootwait, wait, and respawn. initdefault identifies the default run level.
For a description of the other action keywords, see inittab(4). |
process | Defines the command or script to execute. |
Example--Default inittab File
The following example shows an annotated default inittab
file that is installed with the Solaris release:
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 level
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 and identifies the terminal type
| 
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