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The normal Unix boot process has these main phases:
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Basic hardware detection (memory, disk, keyboard, mouse, and the
like) and executing the firmware system initialization program .
In Solaris this is called Boot PROM phase—After you turn on power
to the system, the PROM displays system identification information and
runs self-test diagnostics to verify the system's hardware and memory.
PROM chip contains Forth OpenBoot firmware, and it is executed
immediately after you turn on the system. The primary task of the OpenBoot
firmware is to boot the operating system either from a mass storage
device or from the network. OpenBoot contains a program called the
monitor that controls the operation of the system before the
kernel is available. When a system is turned on, the monitor runs a
power-on self-test (POST) that checks such things as the hardware and
memory on the system. If no errors are found, the automatic boot
process begins. OpenBoot contains a set of instructions that locate
and start up the system's boot program and eventually start up the Unix
operating system.
Locating and running the initial boot program (IPL or bootloader)
from a predetermined location on the disk (MBR in PC). In Solaris the
primary boot program, called bootblk, is loaded from its location
on the boot device (usually disk) into memory.
Locating and starting the Unix kernel. The kernel image file to execute
may be determined automatically or via input to the bootloader. In Solaris
the bootblk program finds and executes the secondary boot program
(called ufsboot) from the Unix file system (UFS) and loads
it into memory. After the ufsboot program is loaded, the
ufsboot program loads the two-part kernel.
The kernel initializes itself and then performs final, high-level
hardware checks, loading device drivers and/or kernel modules as required.
In Solaris the kernel initializes itself and begins loading modules,
using ufsboot to read the files. When the kernel has loaded
enough modules to mount the root file system, it unmaps the ufsboot
program and continues, using its own resources.
The kernel starts the init process, which in turn starts system processes (daemons) and initializes all active subsystems. When everything is ready, the system begins accepting user logins. In Solaris kernel starts the Unix operating system, mounts the necessary file systems, and runs /sbin/init to bring the system to the initdefault state specified in /etc/inittab. The kernel creates a user process and starts the /sbin/init process, which starts other processes by reading the /etc/inittab file. The /sbin/init process starts the run control (rc) scripts, which execute a series of other scripts. These scripts (/sbin/rc*) check and mount file systems, start various processes, and perform system maintenance tasks.
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Availability of svcs -a functionality cannot be legitimately sited as an advantage as it can be easily implemented with th4 old approach (as was done in Red Hat with services command).
I am not sure that conversion of init scripts to Perl cannot achieve the same functionality at lower cost.
The Service Management Facility is a new, unified model for services and service management that is included in the Solaris Operating System. SMF provides a deeper, more functional view into the processes managed during startup and shutdown of a Solaris system. In addition, processes managed through SMF can have dependencies and they are monitored to allow for restarts if a process fails or is improperly stopped.
SMF is a core part of the predictive self-healing technology available in the Solaris 10 OS, and it provides automatic recovery from software and hardware failures as well as administrative errors. In addition, SMF-managed services can be delegated to non-root users. Finally, SMF is a follow-on to the legacy method of starting and stopping services, though
/etc/rc
scripts will continue to run when present for backward compatibility.Deployment of services through SMF provides a much more consistent and robust environment. First, users can query the Solaris OS with a simple command (
svcs -a
) to determine if a service is running, instead of attempting a connection and wondering if the connection will succeed. Additionally, critical services can be restarted automatically in the event of a problem, such as someone inadvertently killing a service, a bug causing a core dump, or other process failures occurring. Further, SMF provides detailed and common logging as well as robust error handling to prevent services from hanging after a system state change. Please see the man page forsmf
(5) for more information.After a typical software installation, there can be a half dozen or more processes that need to be started and stopped during system startup and shutdown. In addition, these processes may depend on each other and may need to be monitored and restarted if they fail. For each process, these are the logical steps that need to be done to incorporate these as services in SMF:
- Create a service manifest file.
- Create a methods script file to define the start, stop, and restart methods for the service.
- Validate and import the service manifest using
svccfg
(1M).- Enable or start the service using
svcadm
(1M).- Verify the service is running using
svcs
(1).Using SAS processes as an example, we will create two services, one for the SAS Metadata Server (OMR) and one for the SAS Object Spawner. In this example, the Object Spawner cannot attempt to start before the OMR is started and should be stopped before the OMR is stopped.
Note If you change an NVRAM setting on a SPARC system and the system will no longer start up, it is possible to reset the NVRAM variables to their default settings by holding down the Stop and N keys simultaneously while the machine is powering up. When issuing this command, hold down Stop+N immediately after turning on the power to the SPARC system; keep these keys pressed for a few seconds or until you see the banner (if the display is available). This is a good technique to force a system's NVRAM variables to a known condition.
Solaris 10 has a new feature boot -m verbose which allows you to customize boot console output.
You too can understand<br> device numbers and mapping in Solaris ...
The following represents a summary of the boot process for a Solaris 2.x
system on Sparc hardware.
Hardware Power ON
message on a large Enterprise
server, or a "'" or "," in the case of an older Ultra system. These
indications will not be present on a monitor connected directly to the
server.
diag-switch?
parameter is
set to true
, output from the POST (Power On Self Test)
will be viewable on a serial terminal. The PROM diag-level
parameter determines the extent of the POST tests. (See the
Hardware Diagnostics page for more information on these settings.)
If a serial terminal is not connected, a prtdiag -v
will
show the results of the POST once the system has booted. If a keyboard
is connected, it will beep and the keyboard lights will flash during
POST. If the POST fails, an error indication may be displayed following
the failure.
diag-switch?
is set, an Entering
OBP
message will be seen on a serial terminal. The MMU (memory
management unit) is enabled. use-nvramrc?
is set to true
,
read the NVRAMRC
. This may contain information about
boot devices, especially where the boot disk has been encapsulated
with VxVM or DiskSuite. ok>
prompt, or by
using prtconf
once the system has been booted. diag-switch?
and
diag-level
are set, additional diagnostics will appear
on the system console.
auto-boot?
: If the auto-boot?
PROM parameter
is set, the boot process will begin. Otherwise, the system will drop
to the ok>
PROM monitor prompt, or (if sunmon-compat?
and security-mode
are set) the >
security
prompt.
The boot process will use the boot-device
and
boot-file
PROM parameters unless diag-switch?
is
set. In this case, the boot process will use the diag-device
and diag-file
.
bootblk
primary boot program from the boot-device
(or diag-device
, if diag-switch?
is set).
If the bootblk
is not present or needs to be regenerated,
it can be installed by running the installboot
command
after booting from a CDROM or the network. A copy of the bootblk
is available at /usr/platform/`arch -k`/lib/fs/ufs/bootblk
/platform/`arch
-k`/ufsboot
is run. This program loads the kernel core image
files. If this file is corrupted or missing, a bootblk: can't
find the boot program
or similar error message will be returned.
/platform/`arch -k`/kernel/unix
/kernel/genunix
/platform/`arch -k`/kernel/sparcV9/unix
/kernel/genunix
As part of the kernel loading process, the kernel banner is displayed to the screen. This includes the kernel version number (including patch level, if appropriate) and the copyright notice.
The kernel initializes itself and begins loading modules, reading
the files with the ufsboot
program until it has loaded
enough modules to mount the root filesystem itself. At that point,
ufsboot
is unmapped and the kernel uses its own drivers.
If the system complains about not being able to write to the root filesystem,
it is stuck in this part of the boot process.
The
boot -a
command singlesteps through this portion of the boot
process. This can be a useful diagnostic procedure if the kernel is
not loading properly.
/etc/system
: The /etc/system
file is read
by the kernel, and the system parameters are set.
The following types of customization are available in the /etc/system
file:
If the /etc/system
file is edited, it is strongly recommended
that a copy of the working file be made to a well-known location. In
the event that the new /etc/system
file renders the system
unbootable, it might be possible to bring the system up with a
boot -a
command that specifies the old file. If this has not
been done, the system may need to be booted from CD or network so that
the file can be mounted and edited.
sched
).
The sched
process is sometimes called the "swapper."
init
).
init
: The init
process reads the
/etc/inittab
and /etc/default/init
and follows
the instructions in those files.
Some of the entries in the /etc/inittab
are:
/etc/rcS
)
/sbin/rc#
)
/etc/rc#.d
directories. They are run by the /sbin/rc#
scripts, each of which corresponds to a
run level. Debugging can often be done on these scripts by adding
echo
lines to a script to print either a "I got this far"
message or to print out the value of a problematic variable.
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