RELEASE NOTES FOR SLURM VERSION 18.08
16 August 2018

IMPORTANT NOTES:
If using the slurmdbd (Slurm DataBase Daemon) you must update this first.

NOTE: If using a backup DBD you must start the primary first to do any
database conversion, the backup will not start until this has happened.

The 18.08 slurmdbd will work with Slurm daemons of version 17.02 and above.
You will not need to update all clusters at the same time, but it is very
important to update slurmdbd first and having it running before updating
any other clusters making use of it.

Slurm can be upgraded from version 17.02 or 17.11 to version 18.08 without loss
of jobs or other state information. Upgrading directly from an earlier version
of Slurm will result in loss of state information.

If using SPANK plugins that use the Slurm APIs, they should be recompiled when
upgrading Slurm to a new major release.

NOTE FOR THOSE UPGRADING SLURMDBD: The database conversion process from
      SlurmDBD 16.05 or 17.02 may not work properly with MySQL 5.1 or 5.5
      (as was the default version for RHEL 6). Upgrading to a newer version of
      MariaDB or MySQL is strongly encouraged to prevent this problem.

NOTE: The slurmctld is now set to fatal if there are any problems with
      any state files.  To avoid this use the new '-i' flag.

NOTE: systemd services files are installed automatically, but not enabled.
      You will need to manually enable them on the appropriate systems:
      - Controller: systemctl enable slurmctld
      - Database: systemctl enable slurmdbd
      - Compute Nodes: systemctl enable slurmd

NOTE: If you are upgrading with any jobs from 14.03 or earlier
      (i.e. quick upgrade from 14.03 -> 15.08 -> 17.02) you will need
      to wait until after those jobs are gone before you upgrade to 17.02
      or 17.11 or 18.08.

NOTE: If you interact with any memory values in a job_submit plugin, you will
      need to test against NO_VAL64 instead of NO_VAL, and change your printf
      format as well.

NOTE: SPANK options handled in local and allocator contexts should be able to
      handle being called multiple times. An option could be set multiple times
      through environment variables and command line options. Environment
      variables are processed first.

NOTE: IBM BlueGene/Q support has been removed.

NOTE: Cray/ALPS is deprecated and will be removed in the 19.05 release.
      You must add the --enable-deprecated option to configure to build
      for this target.

NOTE: Built-in BLCR support is deprecated, no longer built automatically, and
      will be removed in 19.05. You must add --with-blcr and --enable-deprecated
      options to configure to build this plugin.

NOTE: srun will now only read in the environment variables SLURM_JOB_NODES and
      SLURM_JOB_NODELIST instead of SLURM_NNODES and SLURM_NODELIST.  These
      latter variables have been obsolete for some time please update any
      scripts still using them.

NOTE: squeue will now print "UID" as the header for the User ID field;
      corresponding to the %U type specification.

NOTE: slurmd and slurmctld will now fatal if two incompatible mechanisms for
      enforcing memory limits are set. This makes incompatible the use of
      task/cgroup memory limit enforcing (Constrain[RAM|Swap]Space=yes) with
      MemLimitEnforce=yes or with JobAcctGatherParams=OverMemoryKill, which
      could cause problems when a task is killed by one of them while the other
      is at the same time managing that task. The NoOverMemoryKill setting has
      been deprecated in favour of OverMemoryKill, since now the default is
      *NOT* to have any memory enforcement mechanism.

HIGHLIGHTS
==========
 -- Add support for parenthesis in an advanced reservation or job constraint
    specification to group like options together. For example:
    --constraint="[(knl&snc4&flat)*4&haswell*1]" might be used to specify that
    four nodes with the features "knl", "snc4" and "flat" plus one node with
    the feature "haswell" are required. Nodes with those features currently
    available will be favored.
 -- Heterogeneous job steps allocations supported with
    * Open MPI (with Slurm's PMI2 and PMIx plugins) and
    * Intel MPI (with Slurm's PMI2 plugin)
    * No support for Cray systems at this time.
 -- Disable local PTY output processing when using 'srun --unbuffered'. This
    prevents the PTY subsystem from inserting extraneous \r characters into
    the output stream.
 -- Changed slurmd.service file to include "remote-fs.target" in "After" option.
 -- The default AuthType for slurmdbd is now "auth/munge".

CONFIGURATION FILE CHANGES (see man appropriate man page for details)
=====================================================================
 -- Add node and partition configuration options of "CpuBind" in slurm.conf to
    control default task binding. Modify the scontrol to report and modify
    these parameters.
 -- Add "NumaCpuBind" option to knl.conf file to automatically change a node's
    CpuBind parameter based upon changes to a node's NUMA mode.
 -- Add "ValidateMode" configuration parameter to knl.conf for static
    MCDRAM/NUMA configurations.
 -- Add "NodeRebootWeight" option to knl.conf file to modiify a node's
    scheduling weight when rebooting is required to satify a job's constraints.
 -- Add "GetSysStatus" option to burst_buffer.conf file. For burst_buffer/cray
    this would indicate the location of the "dwstat" command.
 -- Add "SetExecHost" flag to burst_buffer.conf to enable access from login node
    for interactive jobs
 -- Configuration parameters "ControlMachine", "ControlAddr", "BackupController"
    and "BackupAddr" in slurm.conf replaced by an ordered list of
    "SlurmctldHost" records with the optional address appended to the name
    enclosed in parenthesis. For example: "SlurmctldHost=head(12.34.56.78)".
    An arbitrary number of backup servers can be configured.
 -- Add "SlurmctldPrimaryOnProg" and "SlurmctldPrimaryOffProg" options to
    slurm.conf to run scripts when primary/backup slurmctld server changes.
 -- Add "ResumeFailProgram" slurm.conf option to specify a program that is
    called when a node fails to respond by the configured "ResumeTimeout".
 -- Remove support for "ChosLoc" configuration parameter.
 -- Add SlurmctldParameters option allow_user_triggers to enable user-defined
    triggers. User defined triggers are now disabled by default.
 -- ConstrainKmemSpace is now disabled by default. In Linux kernel version 3,
    early versions of kernel version 4, and RedHat/CentOS 6 and 7, using
    memory.kmem.limit_in_bytes leaks slab caches, which eventually causes the
    machine to be unable to create new cgroups.
 -- SchedulerParameters' "whole_pack" option has been renamed to "whole_hetjob",
    although "whole_pack" will still be supported for backward compatibility.
 -- Cray: Add "CheckGhalQuiesce" to "CommunicationParameters" in slurm.conf.
 -- Remove requirement to have cgroup_allowed_devices_file.conf in order to
    constrain devices. By default all devices are allowed and GRES, that are
    associated with a device file, that are not requested are restricted.

COMMAND CHANGES (see man pages for details)
===========================================
 -- Add sbatch "--batch" option to identify features required on batch node.
    For example "sbatch --batch=haswell ...".
 -- sacct can report all information about all components of a heterogeneous
    job allocation with "--whole-hetjob=yes" option.
 -- Report cgroup and NodeFeatures plugin configuration with scontrol and
    sview commands.
 -- Add "scontrol show dwstat" command to display Cray burst buffer status.
 -- Remove the "CPUErr" value from the slurm_print_node_table() API call
    ("scontrol show node"). This was always zero for non-BlueGene systems.
 -- srun command returns the highest signal of any task.
 -- Add salloc/sbatch/srun option of "--gres-flags=disable-binding" to disable
    filtering of CPUs with respect to generic resource locality. This option is
    currently required to use more CPUs than are bound to a GRES (i.e. if a GPU
    is bound to the CPUs on one socket, but resources on more than one socket
    are required to run the job).
 -- Add name of partition used to output of "srun --test-only ...". This is
    valuable for jobs submitted to multiple partitions.
 -- Add job reason "ReqNodeNotAvail, reserved for maintenance".
 -- "scontrol reboot" enhancements:
    - Add ability to specify node reason
    - Add ability to specify node state after reboot completion
 -- sdiag command enhancements:
    - Report outgoing message queue contents
    - Report pending job count
 -- Add scontrol ability to create/update "TRESBillingWeights".
 -- Remove "AdminComment +=" syntax from "scontrol update job".
 -- Add sacctmgr options to prevent/manage job queue stuffing:
    - GrpJobsAccrue=<max_jobs>
      Maximum number of pending jobs in aggregate able to accrue age priority
      for this association and all associations which are children of this
      association. To clear a previously set value use the modify command with
      a new value of -1.
    - MaxJobsAccrue=<max_jobs>
      Maximum number of pending jobs able to accrue age priority at any given
      time for the given association. This is overridden if set directly on a
      user. Default is the cluster's limit. To clear a previously set value use
      the modify command with a new value of -1.
    - MinPrioThreshold
      Minimum priority required to reserve resources when scheduling.

OTHER CHANGES
=============
 -- Add new job state of SO/STAGE_OUT indicating that burst buffer stage-out
    operation is in progress.
 -- Add new burst buffer state of "teardown-fail".
 -- Burst buffer errors logged to new job "SystemComment" field.
 -- Enable jobs with zero node count for creation and/or deletion of persistent
    burst buffers.
 -- Avoid terminating other processes in a task group when any task is core
    dumping to avoid incomplete OpenMP core files.
 -- Append ", with requeued tasks" to end of job array "end" email when any task
    is requeued. This is a hint to use "sacct --duplicates" to see all job
    accounting information.
 -- Consider nodes in "Resuming" state as available for backfill future
    scheduling and do not replace in advanced reservations.
 -- Explicitly shutdown the slurmd daemon when reboot requested.
 -- Calculate TRES billing values at job submission to enforce QOS DenyOnLimit
    configuration.
 -- Add acct_gather_profile/influxdb plugin to store job profiling information
    to InfluxDB rather than HDF5.
