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--- reserve [2016/12/12 11:08] – onicolas
+++ reserve [2017/07/26 12:09] – mimbert
@@ Line 8: / Line 8: @@
 The role of //OAR// is to schedule node reservations. It manages **jobs** associated with users. A job has a start time, a duration (walltime), and uses some resources (CorteXlab nodes).
+==== Submissions ====
 The principle of operation of CorteXlab is that users submit jobs to OAR. When the job starts, the user gets exclusive access to the platform, and inside an OAR job, the user can perform (interactively, or in batch) one or several experiments.
@@ Line 21: / Line 23: @@
 This command will wait for the resources to be available, and as soon as they are (i.e. -I stands for interactive), a job is allocated, is started, and a subshell is instantiated where you can work on experiments. As soon as the subshell is closed, the job ends. (It can be useful to work in a [screen](https://www.gnu.org/software/screen/) session to avoid losing jobs in case of network disconnection).
-By default OAR submissions are scheduled as soon as possible. It is also possible to ask for an OAR //reservation// where you choose the date at which the job will be scheduled.
+Submissions may not be interactive. You can provide a script name to execute when the job starts. It has the strong advantage that it allows you to avoid waiting for the job start, which can be long if the platform is heavily used. But for this to work you have to automate everything:
+<code>$ oarsub -l nodes=BEST '/path/to/script/to/execute/when/job/starts script args'</code>
+A particular case of this syntax is:
+<code>$ oarsub -l nodes=BEST 'sleep 1000000'</code>
+It allows you to have a job which is not tied to a terminal, but you still need to manually submit minus tasks when the job starts
+==== Reservations ====
+By default OAR submissions are scheduled as soon as possible. It is also possible to ask for an OAR //reservation// where you choose the date at which the job will be scheduled.
 This other simple example is reserving all the nodes on the 18 of September 2015 from 10AM to 11AM:
@@ Line 28: / Line 41: @@
 <code>$ oarsub -l nodes=BEST,walltime=1:00:00 -r "2015-09-18 10:00:00" </code>
-This command will wait for the resources to be available, and as soon as they are, a job is allocated, is started, and a subshell is instantiated where you can work on experiments. As soon as the subshell is closed, the job ends. (It can be useful to work in a [screen](https://www.gnu.org/software/screen/) session to avoid losing jobs in case of network disconnection).
+==== Booking specific nodes ====
-By default OAR submissions are scheduled as soon as possible. It is also possible to ask for an OAR //reservation// where you choose the date at which the job will be scheduled.
+If you want to reserve specific nodes, there are several possible syntaxes.
+To make a submission using two nodes:
+<code>$ oarsub -I -l nodes=2</code>
+But the nodes will be randomly chosen by OAR, so you'll have to adapt your task's scenario to the allocated nodes.
+It is possible to ask for explicit nodes with a less user-friendly syntax (especially in situations where you need lots of nodes). For example, to make a submission using specifically nodes 4 and 6, for a 30 minutes job:
+<code>$ oarsub -l {"network_address in ('mnode4.cortexlab.fr', 'mnode6.cortexlab.fr')"}/nodes=2,walltime=0:30:00</code>
+==== Advanced usage: sharing the platform ====
+It is possible to share the platform, for specific situations such as tutorials, courses, challenges. In these situations, you want several users to be able to use the platform at the same time. For this, you need to follow these steps:
+The organizer of the tutorial/course/challenge submits or reserve the the whole (or part of) the platform for the duration of the event, with the ''-t container'' option:
+<code>$ oarsub -l nodes=BEST,walltime=4:00:00 -t container=tuto-xyz -r '2018-07-21 14:00:00'</code>
+This will reserve all available nodes for a 4 hours event, between 14 and 18 on July 21, 2018.
+Then, participants can submit jobs inside the container job with this (example) syntax:
+<code>$ oarsub -t inner=tuto-xyz -l {"network_address in ('mnode4.cortexlab.fr', 'mnode6.cortexlab.fr')"}/nodes=2,walltime=0:30:00 -I</code>
+or (another example):
+<code>$ oarsub -t inner=tuto-xyz -l nodes=2,walltime=0:30:00 'sleep 10000000'</code>
+alternatively, the organizer can use:
+<code>$ oarsub -l nodes=BEST,walltime=4:00:00 -t container -r '2018-07-21 14:00:00'</code>
+Then, participants will have to use:
+<code>$ oarsub -t inner=<job_id of the container job> -l nodes=2,walltime=0:30:00 'sleep 10000000'</code>
+==== OAR Documentation ====
+The complete OAR documentation, with much more details and examples, is available here: https://oar.imag.fr