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Periodic and scheduled services with SMF

14 July 2015

Check out Glynn Foster's blog post on one of the exciting new enhancements in Oracle Solaris 11.3, the Beta of which was released last week...

With the release of Oracle Solaris 11.3 Beta last week, we've introduced a metric ton of new features. I'm really excited by the direction Oracle Solaris has been taking ad we continue to modernise the platform, include software administrators and developers are using on other platforms, and generally ensure we're ready to support the next generation of applications and infrastructure. If you've not really been following along, I'd strongly suggest you download Oracle Solaris 11.3 and have a play.

Back in 2005, we took the brave step to move away from /etc/init.d and introduced the Service Management Facility (SMF) as the main way to manage application and system services. SMF provided us with automatic service dependencies, central logging, structured configuration management, reliable application restart in the event of hardware or software failures as part of the overall fault management architecture in Oracle Solaris, and a much, much easier way of administering services. Better still, we converted all the system services over to SMF straight away and improved startup performance as we could now graph service dependencies and identify issues. You can under estimate the significance of this work, especially if you've read the turbulent history of systemd.

That was then, and this is now. One of the exciting enhancements in Oracle Solaris 11.3 relates to SMF, the introduction of the periodic and scheduled services. In another bold move, we're hoping to knock cron off it's block. There's no doubt cron is a foundation of scheduling in UNIX and Linux environments, and will be for years to come. But with scheduled SMF services we take all the ability of cron and combine them with all the benefits of SMF.

Creating an SMF periodic service is easy, with a simple addition to your SMF manifest to describe a periodic method (or using svcbundle):

In the above snippet, we can see that we're executing /usr/local/bin/db_check every 10-11 minutes (as indicated by a jitter attribute of 60 seconds) with a maximum of 30 seconds delay after the service has been transitioned to the online state. We've also given it a method credential to run the script as the oracle user with dba group. The svc:/system/svc/periodic-restarter:defaultservice instance will be responsible for restarting this service periodically.

Scheduled services are services that are run at a specific time, perhaps at an off-peak time. Similarly these are easy to create with a simple addition to your SMF manifest (or again by using svcbundle):

In the above snippet, we can see that we're executing /usr/local/bin/db_backup every day at 2am (as indicated by the hour and minute attributes). In this case the frequency is set as a default value of 1, meaning that we will run this every day. Like the previous example, we have given it a method credential to run the script as the oracle user with dba group. The svc:/system/svc/periodic-restarter:defaultservice instance is also responsible for ensuring this services runs to its defined schedule.

One of the outstanding gaps with the Image Packaging System (IPS) was the ability to associate cron jobs during package install time by locating . Some other platforms have solved this with the introduction of /etc/cron.d using a process of self-assembly of the system's cron entries. We don't support this ability with the cron version included in Oracle Solaris 11. But now using periodic or scheduled services, administrators can simply install their SMF manifests into /lib/svc/manifest/site and restart the svc:/system/manifest-import:default service instance. You can achieve this with an IPS manifest fragment that uses an IPS actuator similar to the following:

file lib/svc/manifest/site/db-backup.xml \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ path=lib/svc/manifest/site/db-backup.xml owner=root group=sys \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ mode=0444 restart_fmri=svc:/system/manifest-import:default

So take the plunge and move your cron entries over to SMF today - you'll not regret it! Our plan is to convert the existing system cron entries over in future releases. For more information, see the following chapters in the excellent Oracle Solaris 11.3 Product Docs:

 
 

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