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- Link to discussion on Developer Forum: http://community.pbspro.org/t/enhancing-pbs-ralter-with-lselect/2074
- Link to pull request : <PR link if available>(phase 1, non-running reservations): https://github.com/openpbs/openpbs/pull/1842
Overview
Right now the only way pbs_ralter can change the shape of a reservation is via the start/end/duration. The resources requested by the reservation can not be altered. The RFE will allow the select resource request to be modified. It will be done in a limited way to start, but it can be enhanced further in the future.
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- This will alter the select spec for a reservation.
- As with modification of start/end times, the request will be sent to the scheduler. The scheduler will attempt to confirm the reservation with the new select spec. The request can be confirmed or denied.
- The requested select spec must request fewer of the same chunks originally requested by the reservation.
- If the reservation has not started yet:
- As with pbs_ralter -R/-E/-D, this may result in the reservation being moved to a completely different set of nodes.
- If a reservation is in in state IN CONFLICT and the reconfirmation is successful, then the reservation will return to state CONFIRMED.
- If the reservation has already started running:
- Attempting to ralter a degraded running reservation will likely fail. This is current behavior of ralter.
- If you attempt to ralter just -R -E -D, the alter will fail.
- If you attempt to alter the select, all of the unavailable nodes will need to be removed for the ralter to succeed.
- This will require the admin to map the resv_nodes chunks to the schedselect chunks and remove the chunks which are unavailable.
- If a reservation is running and in substate IN CONFLICT, the pbs_ralter -l select will be rejected.
- Attempting to ralter a degraded running reservation will likely fail. This is current behavior of ralter.
- If the reservation alter is successful, a 'Y' (reservation confirmation) record will be printed into the accounting logs
- The current behavior of pbs_ralter and standing reservations will not change. The command will only modify the current occurrence.
- This interface can be used along with the -R/-E/-D options.
- Hooks:
- There is no ralter hook. It is not possible for the admin to intercept the incoming select and modify it
- There are submission hooks (rsub/qsub). The select associated with the reservation may not be the same as the user originally submitted.
- To successfully ralter a select, the user should look at the current Resource_List.select for the reservation in pbs_rstat -f before submitting their pbs_ralter -lselect.
- If the requested select is either more of the same chunks or different chunks, the following message will be returned
- "New select must be made up of a subset of the original chunks"
Examples
% pbs_rsub -l select=2:ncpus=2:color=red+2:ncpus=2:color=yellow
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