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May the source be with you, but remember the KISS principle ;-)
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Although the new SMF feature is totally different from the previous boot and daemon management within the Solaris OS, it includes many welcome changes. The system boots faster and can recover from errors, such as hardware failures, that cause services to fail. SMF has some knowledge about knowledge of the state of the system and its services. SMF understands:
This understanding of dependencies allows a new level of service functionality -- if a service fails, SMF can restart not only that particular service but all of the services that depended on it. Thus SMF can fully restore the system to a given run level, even if a core service fails.
With the -m verbose
option, SMF outputs a line for each service that it's starting, which
can help reassure those new to the Solaris 10 OS that everything is
working. Gone, however, are the days of grepping through
/var/adm/messages in hopes of finding an
error that it is actually labeled with the name of the service that is
having a problem. Rather, each service has its own persistent log file.
These are in /var/svc/log for the most part,
with pre-single-user milestone service logs in
/etc/svc/volatile. The system reaches the "login" prompt much
more quickly now, as only the services depended on by login need to
start before login is started.
SMF has improved several aspects of the Solaris administrative model; here are some of the most notable examples:
svcs(1) command)
and managed (using svcadm(1M) and
svccfg(1M)).
svcs -x), as well as individual,
persistent log files for each service.
svcadm(1M)),
allowing the changes to persist across upgrades and patches.
smf_security(5) man page).
Despite these changes, compatibility with existing administrative practices has been preserved wherever possible. For example, most site-local and ISV-supplied rc scripts still work as usual.
Enabling and Disabling Services
Releases prior to the Solaris 10 OS haven't offered a good way to
permanently disable a service. The typical method used is to rename the
relevant rc script to a name that won't get executed, but that change
will be overlooked the next time the system is upgraded. Furthermore,
inetd-based services are enabled and disabled by a totally different
method -- editing a configuration file. Under SMF, both types of
services can be configured using the svcadm(1M)
command, and the changes will persist if the machine is upgraded. Here's
a comparison of how to enable and disable some services.
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The last argument to svcadm in these
examples is the Fault Managed Resource Identifier (FMRI) of the service.
Note that svcadm should only be used for
SMF services -- legacy rc script-controlled services work the same as
in past releases.
Stopping, Starting, and Restarting Services
Traditionally, services have been started by an rc script run at
boot, run with the argument start. Some rc
scripts provide a stop option, and a few also
allow restart. In SMF, these tasks are all
accomplished with the svcadm(1M) command, as
shown in the following table.
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The -t option to
svcadm enable and svcadm disable
indicates that the requested action should be temporary -- it will not
affect whether the service is started the next time that the system
boots. This is in contrast to the
Enabling and Disabling Services example.
As with the enabling and disabling of services,
svcadm should not be used to control rc script-controlled
services; they continue to work the same as in past releases.
Observing the Boot Process
As mentioned in the Notable Changes section of the QuickStart guide, the boot process is much quieter by default than in previous releases of Solaris. This was done to reduce the amount of uninformative "chatter" that might obscure any real problems that might occur during boot.
Some new boot options have been added to control the verbosity of
boot. One that you may find particularly useful is
-m verbose, which prints a line of information when each service
attempts to start up. This is similar to the default boot mode for some
other UNIX-based and UNIX-like operating systems. Verbose boot looks
like this:
{1} ok boot -m verbose
Rebooting with command: boot -m verbose
Boot device: /pci@1c,600000/scsi@2/disk@0,0:a File and args: -m verbose
SunOS Release 5.10 Version Generic 64-bit
Copyright 1983-2004 Sun Microsystems, Inc. All rights reserved.
Use is subject to license terms.
[ network/pfil:default starting (pfil) ]
[ network/loopback:default starting (Loopback network interface) ]
[ system/filesystem/root:default starting (Root filesystem mount) ]
Oct 18 13:53:02/13: system start time was Mon Oct 18 13:52:57 2004
[ network/physical:default starting (Physical network interfaces) ]
[ system/filesystem/usr:default starting (/usr and / mounted read/write) ]
( more service messages elided )
[ system/filesystem/local:default starting (Local filesystem mounts) ]
[ network/ntp:default starting (network time protocol (NTP)) ]
[ system/utmp:default starting (utmpx monitoring) ]
[ system/filesystem/local:default starting (Local filesystem mounts) ]
[ system/console-login:default starting (Console login) ]
demobox console login: checking ufs filesystems
/dev/rdsk/c0t0d0s7: is logging.
Oct 18 13:53:14/50: system/system-log:default starting
Oct 18 13:53:14/51: network/inetd:default starting
Oct 18 13:53:14/52: system/cron:default starting
( more service messages elided )
The order of the service start messages may change from boot to boot, because SMF starts services in parallel according to their dependency relationships.
If a service fails to start successfully, warning messages will be printed in addition to the start message. Here's an example where the NTP service failed to start up:
[ system/filesystem/local:default starting (Local filesystem mounts) ]
[ network/ntp:default starting (network time protocol (NTP)) ]
Oct 25 13:58:42/49 ERROR: svc:/network/ntp:default:
Method "/lib/svc/method/xntp" failed with exit status 96.
Oct 25 13:58:42 svc.startd[4]: svc:/network/ntp:default:
Method "/lib/svc/method/xntp" failed with exit status 96.
[ network/ntp:default misconfigured (see 'svcs -x' for details) ]
[ system/utmp:default starting (utmpx monitoring) ]
( more service messages elided )
The first two error messages would appear during both normal boot and
verbose boot; the last one (network/ntp:default
misconfigured ...) would only appear during verbose boot.
Discovering What's Going Wrong
The Solaris OS has not had a comprehensive place to look for problems
with system services. Some solutions exist to help catch and diagnose
these problems, ranging from coreadm(1M)
logging to site-specific monitoring scripts to comprehensive products
such as Sun Cluster. The new svcs(1) command
includes an "explain" option (svcs -x), which
prints out detailed, solution-driven messages about the services that
are not running. svcs -x shows when and why
the service failed, provides pointers to more information about the
problem, and lists what other services are affected by this problem.
Let's continue with the example of the NTP service failing to start up:
# svcs -x svc:/network/ntp:default (Network Time Protocol (NTP).) State: maintenance since Mon Oct 18 13:58:42 2004 Reason: Start method exited with $SMF_EXIT_ERR_CONFIG. See: http://sun.com/msg/SMF-8000-KS See: ntpq(1M) See: ntpdate(1M) See: xntpd(1M) Impact: 0 services are not running.
The NTP service has been placed into maintenance mode because the
startup script indicated a problem with the service's configuration.
Further information about the service failure is available in the
service's log file in the /var/svc/log
directory (or the /etc/svc/volatile
directory). The log file name is based off the short form of the FMRI,
with instances of "/" replaced by "-". So the log file for the
svc:/network/ntp:default service is
/var/svc/log/network-ntp:default.log. This
log file quickly led to the conclusion that the NTP daemon's
configuration file, /etc/inet/ntp.conf, had
been removed.
Another example shows SMF's ability to track dependencies and point
out problems relating to disabled services. We use the
-v option in this example to see the list of
impacted services.
# svcs -x -v
svc:/application/print/server:default (LP Print Service)
State: disabled since Mon Oct 18 16:17:27 2004
Reason: Disabled by an administrator.
See: http://sun.com/msg/SMF-8000-05
See: man -M /usr/share/man -s 1M lpsched
Impact: 1 service is not running:
svc:/application/print/rfc1179:default
Here, the application/print/server:default
service has been explicitly disabled, but another service that depended
on it (application/print/rfc1179:default) was
not disabled. So the disabling of the first service has kept the second
one from running.
Observing Services
In earlier versions of Solaris, the only way to see what services
were available was to use the ps(1) command
and list all the active processes on the system, and then look around
for the names of processes that matched the names of service
applications. Unfortunately, it's very difficult to track things this
way since most systems have many processes, and new services are
introduced with each new version of Solaris and when other software
packages are added. To further complicate the situation, many modern
services are no longer implemented as single processes. Some services
are implemented as collections of processes, multithreaded processes, or
both simultaneously.
The new svcs(1) command makes it much
easier to observe the status of a system service. The
-p option shows all the processes associated
with a service:
% svcs -p network/smtp:sendmail
STATE STIME FMRI
online 18:20:30 svc:/network/smtp:sendmail
18:20:30 655 sendmail
18:20:30 657 sendmail
% ps -fp 655,657
UID PID PPID C STIME TTY TIME CMD
root 655 1 0 18:20:30 ? 0:01 /usr/lib/sendmail -bd -q15m
smmsp 657 1 0 18:20:30 ? 0:00 /usr/lib/sendmail -Ac -q15m
The -d option shows what other services
this service depends on, and the -D option
shows what other services depend on this service:
% svcs -d network/smtp:sendmail STATE STIME FMRI online 18:20:14 svc:/system/identity:domain online 18:20:26 svc:/network/service:default online 18:20:27 svc:/system/filesystem/local:default online 18:20:27 svc:/milestone/name-services:default online 18:20:27 svc:/system/system-log:default online 18:20:30 svc:/system/filesystem/autofs:default % svcs -D network/smtp:sendmail STATE STIME FMRI online 18:20:32 svc:/milestone/multi-user:default
We can see that sendmail requires networking, local file systems,
name services, the syslog daemon, and the automount daemon to be running
before it will run, and sendmail itself must be running before the
multi-user milestone can be reached. The service start times (the
STIME column) illustrate that these
dependencies have been followed.
Changing Run Levels
SMF has introduced the concept of milestones, which supplant
the traditional notion of run levels. Run levels provide a basic
description of the set of services running on the machine, traditionally
grouped as the services necessary for one user to log in on the machine
console (run level S), and for multiple users to log in to the machine
(run levels 2 and 3). These system states are represented in SMF as
milestones, which are stable services that represent a group of other
services. svcs -d can be used to see what
services must be running before a milestone is reached.
svcadm(1M) is now the preferred method of
setting the system's default run level. This is done with the
milestone subcommand and the FMRI of a valid
milestone, as seen in Table 3.
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The -d option indicates that the default
milestone should be set to the named FMRI. Without the
-d option, svcadm
milestone transitions the system to the named milestone
immediately.
The boot process has been updated to be aware of milestones. In
addition to the traditional boot -s (boot
into single-user mode), you now have boot -m
milestone=<milestone> to boot to the named
milestone. <milestone>
can be single-user,
multi-user, or multi-user-server, as
well as the special milestones all (all
enabled services online) and none (no
services at all). The none milestone can be
very useful in repairing systems that have failures early in the boot
process.
Booting to the single-user milestone (with -m
milestone=single-user) is slightly different than using the old
boot -s. When the system is explicitly booted
to a milestone, exiting the console administrative shell will not
transition the system to multi-user mode, as boot -s
does. To move to multi-user mode after boot -m
milestone=single-user, use the command svcadm
milestone milestone/multi-user-server:default.
Enabling, Disabling, and Monitoring Legacy Services
Services that are started by traditional rc scripts (referred to as
legacy services) will generally continue to work as they always have.
They will show up in the output of svcs(1),
with an FMRI based on the path name of their rc script, but they cannot
be controlled by svcadm(1M). They should be
stopped and started by running the rc script directly.
As mentioned in the Notable Changes section of the guide, rc scripts may not run at exactly the same point in boot as they had in earlier versions of Solaris. In particular, problems may arise for scripts that depend on running before certain rc scripts provided in the Solaris OS. The vast majority of scripts should continue to work without any trouble, though.
Adding New Services to inetd.conf
The Internet services daemon, inetd(1M),
has been rewritten as part of SMF. It stores all of its configuration
data in the SMF database, rather than /etc/inet/inetd.conf,
allowing the SMF tools to be used to control and observe inetd-based
services.
Most inetd-based services that ship with the Solaris OS will
no longer have entries in inetd.conf.
To
provide compatibility for services which haven't converted to SMF,
entries can still be added to inetd.conf
using the same syntax as always, and the new
inetconv(1M) command will convert the new services to SMF
services. inetconv should always be run after
editing /etc/inet/inetd.conf; it can be run
without any arguments.
SMF and Predictive Self-Healing.
Last modified: June 05, 2008