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Trestles User Guide: Reservations

Trestles allows users to create advanced reservations for the system. These reservations guarantee the availability of nodes for a specified amount of time. Users will need to define the number of nodes, amount of time the nodes are needed, and the window of when to create the reservation.

Reservations are charged for the duration of the reservation * number of nodes * 32 (processors per node) in addition to any jobs that are submitted that make use of the reservation (unless the reservation is cancelled 24 hours before its start time).

Creating a Reservation

  • Users are limited to 2 reservations, with up to 4 nodes per reservation up to 4 hours.
  • The command to create a reservation is user_set_res. The format is:
$ user_set_res --account=<allocation>  --nodes=<#_nodes> 
        --duration=<time_in_seconds> --earliest_start=<time_MM/DD/YYYY>
        --latest_end=<time_MM/DD/YYYY> --email=<email>
For Example: 
$ user_set_res --account=TG-XXXXX --nodes=2 --duration=3600 --earliest_start=10:30_03/10/2011
        --latest_end=15:00_03/10/2011 --email=user@sdsc.edu
creates a reservation that requests 2 nodes for 1 hour starting at earliest 10:30 on March 10, 2011 and ending at the latest 15:00 March 10,2011.

Viewing your reservation

You can find your reservation number by running: 
$ show_res | grep $USER
To view when your reservation will begin/end and which nodes you'll be assigned: 
$ show_res --res=<reservation id> --readable --start --end --node_list
Following our example from above: 
$ show_res | grep $USER
1289412186 ... (user)
$ show_res --res=1289412186 --readable --start --end --node_list
...
ResID           StartTime               EndTime                 NodeList
1289412186  Thu Mar 10 10:30:00 2011  Thu Mar 10 11:30:00 2011  trestles-1-32 trestles-1-4
The reservation will begin at 10:30 on March 10, 2011 and end at 11:30. The scheduler has selected nodes trestles-1-32 and trestles-1-4.

Submitting a job to a reservation

If you want to run a job on the reservation, you'll need to modify your submit script. If you're running an interactive job, your command should be: 
$ qsub -I -q normal -l nodes=<#_nodes>:ppn=<#_ppn>,walltime=HH:MM:SS -v Catalina_res_bind=<reservation_id>,QOS=0
For a submission script: 
$ cat testjob.reservation
#!/bin/bash
#PBS -q normal
#PBS -l nodes=#NODES:ppn=#PPN
#PBS -l walltime=HH:MM:SS
#PBS -A <allocation>
#PBS -v Catalina_res_bind=<reservation_id>
cat $PBS_NODEFILE
cd $PBS_O_WORKDIR
If Catalina_res_bind= is not specified, the job can run in and out of the reservation. The scheduler will try to use the reserved nodes, but may use others if the reservation can't fully contain the job. Also, it's important to note that the scheduler requires a 5 minute padding for job reservations. In the example, the longest job we could request to run in the reservation would be for 55 minutes.

Cancel Reservations

Because the nodes you allocate during a reservation a locked to your account, you are charged for the reservation whether you run jobs on it or not. In order to cancel a reservation: 
$ user_cancel_res <reservation_id>

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