UWMLSC > Beowulf Systems > Medusa
Summary of role's for slave nodes
        services running on slave nodes - NFS, condor, LDAS
                NFS - each node contains some amount of LIGO data*
                condor - each node is a condor worker node
                LDAS - each node is an LDAS worker node**

Working on slave nodes
        stopping condor, on each node
                1. /etc/init.d/condor stop
                        DOES NOT CHECKPOINT JOB!
                2. One of these is preferable, needs testing
                        a./opt/condor/bin/condor_vacate ; /etc/init.d/condor stop


                3. either of option 2 is desired, each causes jobs to
                   checkpoint.  2a results in all condor services being
                   stopped.  2b results in all but condor_master being
                   stopped, after which node can be remotely started.

                   2a sequence - loopRangebg condor_vacate, then condor stop.
                      Do work.  loopRangegbg condor start.
                   2b sequence - from a master (or any condor pool member?)
                      condor_off {hostname or all}.  Do work.  condor_on
                      {hostname or all}.

                4. on restart, does slave node join condor pool?
                      on the node, running the command 
                      "condor_medusa |grep `hostname -s`" will return output
                      (consisting of hostname, status w/ regards to condor,and
                      load) if the machine has joined the pool; it will return
                      nothing if the node has not joined to pool.

        Shutting down nodes makes frame files unavailable!  Avoid doing this
                if jobs are running!!!


*As all nodes contain LIGO data, each is an NFS server, for LIGO jobs to run,
 ALL nodes should theoretically be up!

**Not necessarily true, will not necessarily be true long term 

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