Page Comparison

...

• Visibility: Public
• Change Control: Stable
• Details:
  • Scheduler now has additional attributes which can be set in order to run it.
    • sched_priv - to point to the directory where scheduler keeps the fairshare usage, resource_group, holidays file and sched_config
    • sched_log - to point to the directory where scheduler logs.
    • partition - list name of all the partition /s for which this scheduler is going to schedule jobs.
    • sched_host - hostname on which scheduler is running. For default scheduler it is set to pbs server hostname.
    • sched_port - port number on which scheduler is listening.
    • state - This attribute shows the status of the scheduler. It is a parameter that is set only by pbs server.
  • One can set a partition or a comma separated list of partitions to assign only one partition per scheduler object. Once set, given scheduler object will only schedule jobs from the queues attached to specified partition"
    • qmgr -c "s sched multi_sched_1 partition='part1,part2'"
  • If no partition are is specified for a given scheduler object, other than the default scheduler where no partition value can be set, then that scheduler will not schedule any jobs.
  • By default, All new queues created will be scheduled by the default scheduler, until they have been assigned to a specific partition.
  • A partition once attached to a scheduler can not be attached to a second scheduler without removing it from the first scheduler. If tried, then it will throw following error:
    • qmgr -c "s sched multi_sched_1 partition+='part2'"
      Partition part2 is already associated with scheduler <scheduler name>.
  • Scheduler object "state" attribute will show one of these 3 values  - down, idle, scheduling 
    • If a scheduler object is created but scheduler is not running for some reason state will be shown as "down"
    • If a scheduler is up and running but waiting for a cycle to be triggered the state will be shown as "idle"
    • If a scheduler is up and running and also running a scheduling cycle then the state will be shown as "scheduling "
    • Default scheduler's state is by default "idle" since the "scheduling" of server is set to true with default installation. 
•  
  • The default sched object is the only sched object that cannot be deleted.
  • Trying to set sched_port, sched_priv and sched_host on default scheduler will not be allowed. The following error message is thrown in server_logs when we try to change sched_priv directory.
    • qmgr -c "s sched default sched_priv = /tmp
      Operation is not permitted on default scheduler
  • Trying to start a new scheduler other than the default scheduler, without assigning a partition will throw the following error message in scheduler logs.
             Scheduler does not contain a partition

  • If Scheduler fails to accept new value for its sched_log directory then comment of the corresponding scheduler object at server is updated with the following message.  Also, the scheduling attribute is set to false.
            Unable to change the sched_log directory

  • If Scheduler fails to accept new value for its sched_priv directory then comment of the corresponding scheduler object at server is updated with the following message.  Also, the scheduling attribute is set to false.
           Unable to change the sched_priv directory

  • If PBS validation checks for new value of sched_priv directory do not pass then comment of the corresponding scheduler object at server is updated with the following message. Also, the scheduling attribute is set to false.
          PBS failed validation checks for sched_priv directory
  • If Scheduler is successful in accepting the new log_dir configured at qmgr then the following error message is thrown in the scheduler logs.

           Scheduler log directory is changed to <value of path of the log directory>

  • If Scheduler is successful in accepting the new sched_priv configured at qmgr then the following error message is thrown in the scheduler logs.
           Scheduler priv directory is changed to <value of path of the sched_priv directory> 

  • If we keep on disassociating partitions unsets partition from a scheduler until it does not contain any of the partitions then this scheduler is identical to default scheduler in which case we shutdown this scheduler PBS scheduler will shutdown itself and following error message is thrown logged in scheduler logs.
           Scheduler does not contain a partition.   

  • If Scheduler fails in getting its stats from Server then the following error message is shown in scheduler logs.
           Unable to retrieve the scheduler attributes from server     

  • A new option -I is introduced to provide a name to a scheduler. If we run pbs_sched without this option then it is considered as default scheduler whose name is "default".
           Example: pbs_sched -I sc1 -S 15051
           Here scheduler is started on port number 15051 whose id/name is "sc1".

                                                                                                                                                                                                                                

    
    

...

• Visibility: Public
• Change Control: Stable
• Details:
  • In a Multi-sched environment, reservations can be confirmed by any scheduler servicing their respective partitions.
  • After the reservations are confirmed they are assigned the partition their node solution came from.
  • A scheduler servicing 2 partitions P1, P2 would try to confirm a reservation on nodes from either P1 or P2 but not a mix of both. Once  Once the reservation is confirmed, it has a partition attribute set on it to identify where it was confirmed. Similarly, the reservation queue also gets a partition attribute set on it (matching the reservation).
    • example,Example:

      % pbs_rsub -lselect=1:ncpus=2 -R 1030 -D1200 -I 5
      R865.centos CONFIRMED

      % pbs_rstat -f R865
      Resv ID: R865.centos
      Reserve_Name = NULL
      Reserve_Owner = root@centos
      reserve_type = 2
      reserve_state = RESV_CONFIRMED
      reserve_substate = 2
      reserve_start = Mon Feb 03 10:30:00 2020
      reserve_end = Mon Feb 03 10:50:00 2020
      reserve_duration = 1200
      queue = R865
      Resource_List.ncpus = 2
      Resource_List.nodect = 1
      Resource_List.select = 1:ncpus=2
      Resource_List.place = free
      Resource_List.walltime = 00:20:00
      schedselect = 1:ncpus=2
      resv_nodes = (vnode2:ncpus=2)
      Authorized_Users = root@centos
      server = centos
      ctime = Mon Feb 03 10:08:55 2020
      mtime = Mon Feb 03 10:09:03 2020
      interactive = 5
      Variable_List = PBS_O_LOGNAME=root,PBS_O_HOST=centos,PBS_O_MAIL=/var/spool/mail/arung,PBS_TZID=America/Los_Angeles
      euser = root
      egroup = root
      partition = P3P1

      % qmgr -c "l q R865"
      Queue R865
      queue_type = Execution
      total_jobs = 0
      state_count = Transit:0 Queued:0 Held:0 Waiting:0 Running:0 Exiting:0 Begun:0
      acl_user_enable = True
      acl_users = root@centos
      resources_max.ncpus = 2
      resources_available.ncpus = 2
      enabled = True
      started = False
      partition = P3P1

  • Once a reservation is confirmed and partition is assigned to it, it can not be re-confirmed or altered in any other partition.

  • Reservations (and their queues) confirmed by the default scheduler are marked under partition "pbs-default".

  • PBS assigns a default partition name "pbs-default" to all the reservations (and their queues) confirmed by the default scheduler. If an admin tries to assign a scheduler/queue/node partition name "pbs-default", qmgr command throws error - "Default partition name is not allowed".

...