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Solaris SMF feature is an attempt to upgrade the standard init.d based boot and daemon management scheme typical for Unix System V. They added XML files which makes it more complex, less flexible and more Windows-style, but it does include some useful enhancements.
Still the architecture made this subsystem more complex and less elegant for trivial enhancements in capabilities (and not all of them relevant for servers). In this sense it is subpar and I think that Solaris engineers could provide a better, more Unix-style solution, but we have what we have. In other words they provided capabilities similar that exist in Linux (service and chkconfig utilities) using significantly more complex and less transparent approach.
This understanding of dependencies allows in case of failure to restart not only that particular service, but also "dependent" servicest. Which can be achieved in classic setup too by using pseudo comments (like in Linux) or using a "shadow" dependencies file for each service.
With the -m verbose option, SMF outputs a line for each service that it's starting, which helps to provide a visual feedback for the start-up process. This is a quite welcome addition.
The other change is more controversial and I have impression that it was agents of Microsoft or IBM infiltrated into Sun who lobbies for this change ;-) Instead of grepping through /var/adm/messages to find an error that for the service that is having a problem now we have am extremely questionable "advantage" of having one log file for each service. They are located in /var/svc/log for the most part, with pre-single-user milestone service logs in /etc/svc/volatile.
Major screw up in Solaris 10 and 11: new location of logs and "per service" log split
The system can reach the "login" prompt quicker, as only the services dependent on login need to be started before login is started. Which is a very questionable advantage, as Solaris is a server OS, not a desktop OS, and generally time to login prompt is irrelevant metric for servers, but this feature probably reflects long gone period when Sun has some hopes for the desktop too (at one point they were using Solaris as a desktop system for the staff, which probably was the largest userbase for Solaris 10 desktop ;-)
SMF moves away from Unix simplicity introducing essentially Windows-style solution:
Compatibility with existing administrative practices has been preserved wherever possible. For example, most site-local and ISV-supplied rc scripts still work as usual.
Releases prior to the Solaris 10 did not have a standard 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 can 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 (similar in functionality to Linux chkconfig command with functionality of service command added), and the changes will persist. Here's a comparison of how to enable and disable some services.
|Old Method||SMF Method|
|mv /etc/rc2.d/S75cron /etc/rc2.d/x.S75cron||svcadm disable system/cron:default|
|edit /etc/inet/inetd.conf, uncomment the finger line||svcadm enable network/finger:default|
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.
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.
|Old Method||SMF Method|
|/etc/init.d/sshd stop||svcadm disable -t network/ssh:default|
|/etc/init.d/sshd start||svcadm enable -t network/ssh:default|
|/etc/init.d/sshd stop; /etc/init.d/sshd start||svcadm restart network/ssh:default|
|kill -HUP `cat /var/run/sshd.pid`||svcadm refresh network/ssh:default|
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. for example to enable sshd permanently and to start sshd daemon you can use the command:
svcadm enable network/ssh:default
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.
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:
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: 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.
The Solaris 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 -vn 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.
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.
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.
|Old Method||SMF Method|
|edit /etc/inittab||svcadm milestone -d milestone/single-user:default|
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.
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.
The 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. The vast majority of scripts should continue to work without any trouble, though.
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 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.
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