Wednesday January 26, 2005

With some trepidation I set about porting a very simple rc script to into smf. It seems I should not have been overly concerned. The service in question was a very small Postgres database, which on Solaris 9 had been started from rc3.d. Moving the rc script over to 10 worked but I wanted a fuller smf experience so decided to create a manifest and import that into smf on the zone running the database.

Starting with the start part of the rc script this became:

#!/sbin/sh

FMRI="svc:/appl/postgres"

getproparg() {
        val=`svcprop -p $1 $FMRI`
        [ -n "$val" ] && echo $val
}

p=`getproparg postgres/path`
d=`getproparg postgres/dbdir`
u=`getproparg postgres/user`

PATH=$p:${PATH}
export PATH 

exec /bin/su $u -c "postmaster -i -S -D $d"

It struck me that we are no longer confined to the bourne shell at this point. As long as we depend on the files systems being mounted we could use a more exotic shell, though never the csh. So all the possible options that postgres uses are defined as properties. Then this manifest can be imported and we are away:

<?xml version="1.0"?>

<!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1">

<service_bundle type='manifest' name='postgres'>

<service
        name='appl/postgres'
        type='service'
        version='1'>

        <create_default_instance enabled='true' />

        <dependency
                name='autofs'
                grouping='require_all'
                restart_on='none'
                type='service'>
                <service_fmri value='svc:/system/filesystem/autofs' />
        </dependency>

        <exec_method
                type='method'
                name='start'
                exec='/postgres/svc/method/postgres'
                timeout_seconds='0' />

        <exec_method
                type='method'
                name='stop'
                exec=':kill -15'
                timeout_seconds='3' />

        <property_group name='postgres' type='application'>
                <propval name='user' type='astring' value='postgres' />
                <propval name='path' type='astring' value='/usr/local/pgsql/bin' />
                <propval name='dbdir' type='astring' value='/var/pgsql' />
        </property_group>
</service>
</service_bundle>

It depends on autofs so that if the binaries or the database files are automounted it will be ready.

Then:

# svccfg import postgres.xml

and we are away. Clearly I did not manage to get this right first time, and someone more knowledgeable in smf will tell me I still have not, but this was easy to debug as the output of the script when into /var/smf/log/appl-postgres:default.log.

dredd 5 # svcs -l svc:/appl/postgres:default
fmri         svc:/appl/postgres:default
enabled      true
state        online
next_state   none
restarter    svc:/system/svc/restarter:default
contract_id  27355 
dependency   require_all/none svc:/system/filesystem/autofs (online)
dredd 6 # 

Now killing postgres using kill or pkill results in the database being restarted. Nice.

This was on a zone running build 67 so things may appear different in the released version.