glossary: add additional terms

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glossary.rst

@@ -25,18 +25,51 @@ throughout the various guides and docs on our sites.
   loads all the important job, scheduling, and resource related services for
   Flux.
 
+.. _flux-imp:
+
+**Flux IMP (Independent Minister of Privilege)**
+  A system service that allows instance owners to run work on behalf of a guest.
+  In other words, it allows multiple users to use / run jobs on a :ref:`Flux
+  instance<flux-instance>` instead of just the owner.  More of the nitty gritty
+  details can be found in
+  `RFC 15 <https://flux-framework.readthedocs.io/projects/flux-rfc/en/latest/spec_15.html>`_.
+
 .. _flux-instance:
 
 **Flux Instance**
   A group of flux-broker processes which are launched via any parallel launch
   utility that supports PMI (Process Manager Interface).
 
+.. _flux-shell:
+
+**Flux Shell**
+  A component of Flux that manages the startup and execution of user jobs.  You
+  can read more in the :core:man1:`flux-shell` manpage.
+
 .. _fluid:
 
 **FLUID (Flux Locally Unique ID)**
   IDs used to represent Flux jobs, defined by
   `RFC 19 <https://flux-framework.readthedocs.io/projects/flux-rfc/en/latest/spec_19.html>`_.
 
+.. _fractal-scheduling:
+
+**Fractal Scheduling**
+  A term that is sometimes used to describe a tree of
+  :ref:`Flux instances<flux-instance>` that are greater than 2 in depth.  In
+  other words, a Flux :ref:`sub-instance<sub-instance>` that has launched
+  additional Flux sub-instances.
+
+.. _fsd:
+.. _flux_standard_duration:
+
+**FSD (Flux Standard Duration)**
+  A Flux standard for human readable time durations.  Generally speaking, the
+  suffixes of 'ms', 's', 'm', 'h', 'd' are used to indicate time in
+  milliseconds, seconds, minutes, hours, or days respectively.  The specifics
+  can be found in
+  `RFC 23 <https://flux-framework.readthedocs.io/projects/flux-rfc/en/latest/spec_23.html>`_.
+
 .. _hostlist:
 
 **Hostlist**
@@ -84,6 +117,43 @@ throughout the various guides and docs on our sites.
   Maximum values that are enforced across jobs, queues, and users, such as time
   and/or resource limits.
 
+.. _queue:
+.. _job_queue:
+
+**Queue**
+  A job management data structure that contains sets of jobs in priority order.
+  Multiple queues may be configured for a :ref:`Flux instance<flux-instance>`.
+  Queues may differ in what resources are assigned to them, which users are
+  allowed to submit to them, and what defaults/limits may exist for them.  Often
+  may be called a "job queue."
+
+.. _queue_enable:
+.. _queue_disable:
+.. _queue_start:
+.. _queue_stop:
+
+**Queue Enable/Disable/Start/Stop**
+  In Flux, the terms "enable"/"disable" are used to describe if jobs can be
+  submitted to a queue.  The terms "start"/"stop" are used to describe if jobs
+  can be executed.  Under normal operations, a queue is "enabled"/"started,"
+  which allows users to submit jobs and jobs can run.  If a queue is
+  "enabled"/"stopped," it means jobs can be submitted but not allowed to run.
+  This situation is common if resources are temporarily down for maintenance.
+  If a queue is "disabled"/"started," previously submitted jobs can run, but no
+  more jobs can be submitted going forward.  This situation is common if
+  administrators want to take down resources in the future and want currently
+  running jobs to finish.
+
+.. _queue_drain:
+.. _queue_idle:
+
+**Queue Drain/Idle**
+  In Flux, the term "drain" is used for waiting for a queue to be empty.  It is
+  common to wait for a queue to drain after a queue is
+  :ref:`disabled<queue_disable>`.  The term "idle" Is used for waiting for all
+  running jobs to finish.  It is common to wait for a queue to idle after a
+  queue is :ref:`stopped<queue_stop>`.
+
 .. _pmi:
 
 **PMI (Process Manager Interface)**
@@ -123,3 +193,51 @@ throughout the various guides and docs on our sites.
 **Shell Plugins**
   Extensions of a job's environment that can be configured on a per-job basis
   using the ``--setopt`` option of the :core:man1:`flux-mini` commands.
+
+.. _single-user-mode:
+
+**Single User Mode**
+  A :ref:`Flux instance<flux-instance>` that is used by only one user.  This is
+  a common use case when a user runs a :ref:`sub-instance<sub-instance>` only
+  for themselves.
+
+.. _sub-instance:
+
+**Sub-Instance**
+  A :ref:`Flux instance<flux-instance>` that is run as a job within another Flux
+  instance.  This is commonly done if a user wants to schedule / control a set
+  of resources themselves outside of the parent instance.  It is commonly done
+  in :ref:`single user mode<single-user-mode>`.
+
+.. _system-instance:
+
+**System Instance**
+  A :ref:`Flux instance<flux-instance>` that is available to all users on a set
+  of resources.  Most users will think of this as the "installed" or "default"
+  resource manager/scheduler on a system.
+
+.. _TBON:
+
+**TBON (Tree Based Overlay Network)**
+  The overlay network that :ref:`Flux brokers<flux-broker>` wire up amongst
+  themselves in a :ref:`Flux instance<flux-instance>`.
+
+.. _URI:
+
+**URI (Universal Resource Identifier)**
+  Common resource identifier used by many technologies.  Used in Flux for
+  identification of :ref:`Flux brokers<flux-broker>`.  See
+  `Wikipedia page <https://en.wikipedia.org/wiki/Uniform_Resource_Identifier>`_
+  for general overview.
+
+.. _workflow:
+
+**workflow**
+  The
+  `Webster's dictionary <https://www.merriam-webster.com/dictionary/workflow>`_
+  definition is "the sequence of steps involved in moving from the beginning to
+  the end of a working process."  In the context of Flux, this is usually a
+  series or collection of jobs that users execute to accomplish some task.
+  Although not required, typically jobs will be run in a certain order.  A
+  number of jobs in the workflow have dependencies and cannot run until prior
+  jobs in the workflow complete.