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diff --git a/doc/dev/crimson/backfillmachine.rst b/doc/dev/crimson/backfillmachine.rst new file mode 100644 index 00000000000..3f579621ad4 --- /dev/null +++ b/doc/dev/crimson/backfillmachine.rst @@ -0,0 +1,26 @@ +=============== +BackfillMachine +=============== + + +In Crimson, backfill is implemented with `Boost State Chart <https://www.boost.org/doc/libs/1_86_0/libs/statechart/doc/>`_. + +.. //TODO: Once the implementation is settled: +.. * Explain exceptional states once we finish working on this code +.. * Explain example happy path flow (code walkthorugh?) +.. * https://tracker.ceph.com/issues/68728 + +A sample of the recent state model: + +.. note:: ``Cancelled`` and ``Crushed`` states are not included in the + following graph in order to make it easier to follow: + + * **Any** state is able to transit into ``Crushed``. + + * **Any** state (except from ``Initial`` and ``Waiting``) can transit into ``Cancelled`` + +.. image:: crimson_backfillmachine.svg + + +In similarly to :doc:`/dev/peering` a copy of the latest BackfillMachine +state model can be genereated using the `gen_state_diagram.py <https://github.com/ceph/ceph/blob/master/doc/scripts/gen_state_diagram.py>`_ |