This is my job_conf.xml :
<?xml version="1.0"?>
<job_conf>
<plugins workers="4">
<plugin id="local" type="runner" load="galaxy.jobs.runners.local:LocalJobRunner" workers="4"/>
<plugin id="pbs" type="runner" load="galaxy.jobs.runners.pbs:PBSJobRunner" workers="8"/>
</plugins>
<handlers default="batch">
<handler id="node01" tags="batch"/>
<handler id="node02" tags="batch"/>
</handlers>
<destinations default="regularjobs">
<destination id="local" runner="local"/>
<destination id="regularjobs" runner="pbs" tags="cluster">
<param id="Resource_List">walltime=24:00:00,nodes=1:ppn=4,mem=10G</param>
<param id="galaxy_external_runjob_script">scripts/drmaa_external_runner.py</param>
<param id="galaxy_external_killjob_script">scripts/drmaa_external_killer.py</param>
<param id="galaxy_external_chown_script">scripts/external_chown_script.py</param>
</destination>