+
+ControlMachine=uuid_prefix.your.domain
+SlurmctldPort=6817
+SlurmdPort=6818
+AuthType=auth/munge
+StateSaveLocation=/tmp
+SlurmdSpoolDir=/tmp/slurmd
+SwitchType=switch/none
+MpiDefault=none
+SlurmctldPidFile=/var/run/slurmctld.pid
+SlurmdPidFile=/var/run/slurmd.pid
+ProctrackType=proctrack/pgid
+CacheGroups=0
+ReturnToService=2
+TaskPlugin=task/affinity
+#
+# TIMERS
+SlurmctldTimeout=300
+SlurmdTimeout=300
+InactiveLimit=0
+MinJobAge=300
+KillWait=30
+Waittime=0
+#
+# SCHEDULING
+SchedulerType=sched/backfill
+SchedulerPort=7321
+SelectType=select/cons_res
+SelectTypeParameters=CR_CPU_Memory
+FastSchedule=1
+#
+# LOGGING
+SlurmctldDebug=3
+#SlurmctldLogFile=
+SlurmdDebug=3
+#SlurmdLogFile=
+JobCompType=jobcomp/none
+#JobCompLoc=
+JobAcctGatherType=jobacct_gather/none
+#
+# COMPUTE NODES
+NodeName=DEFAULT
+PartitionName=DEFAULT MaxTime=INFINITE State=UP
+PartitionName=compute Default=YES Shared=yes
+
+NodeName=compute[0-255]
+PartitionName=compute Nodes=compute[0-255]
+
+
+
+h3. SLURM configuration essentials
-On compute nodes:
+Whenever you change this file, you will need to update the copy _on every compute node_ as well as the controller node, and then run @sudo scontrol reconfigure@.
-* @pip install --upgrade pyvcf@
+*@ControlMachine@* should be a DNS name that resolves to the SLURM controller (dispatch/API server). This must resolve correctly on all SLURM worker nodes as well as the controller itself. In general SLURM is very sensitive about all of the nodes being able to communicate with the controller _and one another_, all using the same DNS names.
-h4. Crunch user account
+*@NodeName=compute[0-255]@* establishes that the hostnames of the worker nodes will be compute0, compute1, etc. through compute255.
+* There are several ways to compress sequences of names, like @compute[0-9,80,100-110]@. See the "hostlist" discussion in the @slurm.conf(5)@ and @scontrol(1)@ man pages for more information.
+* It is not necessary for all of the nodes listed here to be alive in order for SLURM to work, although you should make sure the DNS entries exist. It is easiest to define lots of hostnames up front, assigning them to real nodes and updating your DNS records as the nodes appear. This minimizes the frequency of @slurm.conf@ updates and use of @scontrol reconfigure@.
-On compute nodes and controller:
+Each hostname in @slurm.conf@ must also resolve correctly on all SLURM worker nodes as well as the controller itself. Furthermore, the hostnames used in the configuration file must match the hostnames reported by @hostname@ or @hostname -s@ on the nodes themselves. This applies to the ControlMachine as well as the worker nodes.
-* @adduser crunch@
+For example:
+* In @/etc/slurm-llnl/slurm.conf@ on control and worker nodes: @ControlMachine=uuid_prefix.your.domain@
+* In @/etc/slurm-llnl/slurm.conf@ on control and worker nodes: @NodeName=compute[0-255]@
+* In @/etc/resolv.conf@ on control and worker nodes: @search uuid_prefix.your.domain@
+* On the control node: @hostname@ reports @uuid_prefix.your.domain@
+* On worker node 123: @hostname@ reports @compute123.uuid_prefix.your.domain@
-The crunch user should have the same UID, GID, and home directory on all compute nodes and on the controller.
+h3. Automatic hostname assignment
-h4. Repositories
+If your worker node bootstrapping script (see "Installing a compute node":install-compute-node.html) does not send the worker's current hostname, the API server will choose an unused hostname from the set given in @application.yml@, which defaults to @compute[0-255]@.
+
+If it is not feasible to give your compute nodes hostnames like compute0, compute1, etc., you can accommodate other naming schemes with a bit of extra configuration.
+
+If you want Arvados to assign names to your nodes with a different consecutive numeric series like @{worker1-0000, worker1-0001, worker1-0002}@, add an entry to @application.yml@; see @/var/www/arvados-api/current/config/application.default.yml@ for details. Example:
+* In @application.yml@: