Specify Server for DBMS_Scheduler Job in Policy Managed RAC
dbms_scheduler.set_attribute is what you're looking for - it forces a job to run on a given node (specified by instance_id):

begin
dbms_scheduler.create_job (
job_name=&gt;'PHIL',
job_type=&gt;'plsql_block',
job_action=&gt;'NULL;',
repeat_interval=&gt;'freq=minutely;interval=2');

end;
/

begin
dbms_scheduler.set_attribute('PHIL','instance_id',1);
end;
/


dba_scheduler_jobs.instance_id will be NULL unless you have explicitly set it with set_attribute.

I realise that this isn't what you asked, but it's easier than messing with pools!