Oozie problem with multiple servers-Same job run by all servers

I have Amabri – <span style=”font-family: ‘Helvetica Neue’, Helvetica, Arial, sans-serif; font-size: 14px; line-height: 20px;”>2.1.0 with HDP 2.3 (Oozie 4.2.0).</span>

I have installed oozie server on 3 linux machines and oozie client on 6 machines.

I am using MySQL as oozie database.

Now when I make a coordinator job and run it – then there is sometimes 3 instances of the Job (workflow job specified in workflow.xml) running simultaneously. This is happening many times.

is this something because I have 3 oozie servers running side by side? But this should have been managed internally by oozie right? OR I am missing some configuration?

below is my coordinator.xml

<coordinator-app name=”TEST-COORDINATOR” frequency=”5″ start=”2015-09-23T12:53Z” end=”2015-10-23T00:00Z” timezone=”US/Eastern” xmlns=”uri:oozie:coordinator:0.1″>

<controls>

<concurrency>1</concurrency>

</controls>

<action>

<workflow>

<app-path>/path/to/job.xml</app-path>

</workflow>

</action>

</coordinator-app>