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https://pbspro.atlassian.net/browse/PP-864

Overview:

Cray X* series systems have the ability to support suspending one or more jobs to run a higher priority job.  PBS needs to modify the suspend pseudo signal (used by the qsig command and preemption) to support doing suspend and resume on a Cray X* series.

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• Cray systems with a Gemini interconnect do NOT support suspend/resume
• Cray systems with an Aries interconnect and newer Cray X* series systems DO support suspend/resume 
• in order to do suspend/resume set suspendResume 1 in /etc/opt/cray/alps/alps.conf (using xtopview on CLE 5.2 and prior CLEs) and then restart ALPS
  • Please refer to Cray's System Administration Guide for more details about using suspend/resume on Cray X* series
• On Cray X series system PBS issues a request to ALPS to switch IN (resume) or OUT (suspend) an ALPS reservation.

Interface #1 -

Log messages that will appear in the MoM logs:

MoM log message #1:  "ALPS reservation <ALPS reservation ID> SWITCH status is = 'EMPTY'"

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 New error code when ALPS fails to switch reservation from suspend to resume or resume to suspend

• Change Control: Stable
• Details:
  
  • New error code "15219" will be returned for pbs_sigjob() IFL call when ALPS fails to switch reservation in mom.
  • Command "qsig" will print the following error message when ALPS fails to switch reservation
    "qsig: Switching ALPS reservation failed <job id>"

Interface #2 - New mom log messages

• Change Control: Unstable
• Details:
  
  • Following mom log message is logged on Cray X series systems when 
    • PBS tries to suspend/resume a job (PBSEVENT_DEBUG2)-
      "Switching ALPS reservation <ALPS reservation id> to <suspend/resume>"
    • ALPS fails to accept a reservation switch request (PBSEVENT_SYSTEM)-
      "Failed to switch <OUT/IN> ALPS reservation"
    • PBS issues the ALPS reservation switch request successfully (PBSEVENT_DEBUG2)-
      "Made the ALPS SWITCH request"
    • It is possible to incorrectly get an 'EMPTY' response (which means there is no claim on the ALPS reservation) when in reality there is a claim on the ALPS reservation.  PBS will print this log message so it is possible to see how often the false 'EMPTY' response is received
  .

Interface 2 -

New error code when ALPS fails to switch reservation from suspend to resume or resume to suspend

• Stable
• New error code "15219" will be returned for pbs_sigjob() IFL call when ALPS fails to switch reservation in mom.
• Command "qsig" will print the following error message when ALPS fails to switch reservation
  "qsig: Switching ALPS reservation failed <job id>"

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• • • (PBSEVENT_DEBUG2).
      "ALPS reservation <ALPS reservation ID> SWITCH status is = 'EMPTY'"