SMF Tech Talk notes from OSDevCon
Service Management Facility, Detlef Drewanz
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Immediate questions folks ask about SMF:
What is manifest loading?
Can I switch it off?
Where are the scripts?
SMF is a common service management framework
System administrators have to live with this system
Complete change in the boot process
We now have service dependencies
In S10 we have same number of services, but different dependencies, so we do things in parallel during the boot process, no longer is it sequential, it is milestone-based. So, we get better, more explicit indication of the fixed definition state of the system for a particular milestone. Now developers can introduce a new milestone. Benefit: You can switch to milestone3, test it, then go back to milestone2, test, go forward, etc. Couldn't do that before.
Also have automated restart of services, and secure delegation of administrative tasks.
SMF gives us common service development and deployment framework using service manifests, and includes handling for upgrade. Formalizes the service development and makes common start stop, etc.
Next questions:
How do I identify a service: FMRI, fault managed resource ID
How do I describe a service: Service Manifest XML file
-name it using FMRI
-define dependencies
-create methods (start/stop/refresh) with properties
%svcadm enable 'service-name'
To create your own service, use this
HowTo
Because the manual is good, but sometimes the manual is not so good.
[note] I asked Detlef for further information about this statement after his talk and he said the following:
Documentation is spread across too many web sites and we need one place to go for information. However, he also did say that it was useful to have the How To articles, so it is a difficult problem to solve. He said that he would not expect to find the information about SMF in the Advanced Administration Guide and felt strongly that SMF needs its own document, its own book, because folks are unlikely to find it in Adv. Admin Guide, but he did find it there, by using search, and was surprised by that location. He felt that the information should be in the developer's collection or on OpenSolaris.org and the information should describe development of manifests.
SysAdmins love SMF largely because the status of the service is maintained across the upgrades.
Questions:
What is different between restart and refresh? Restart is stop and start, refresh is just refresh cache or re-read the config files.
[note] This question received loud comment from many folks, it was a very experienced crowd, so no dumb questions aloud, pretty typical UG audience, IMHO. Ask a newbie question and the group roars back with a response like, 'of course you need both restart and refresh and how could you be so silly to not understand the difference'.
