95784428a4
This page is huge and keeps growing. So: * Move additional topics to sub-documents. * Move ESP creation to the install guide (it's not even Redfish-specific). * Create a generic firmware updates document. Provide a feature listing at the top for easier navigation. Change-Id: Ic58c139da5e1e60f5ce4d2cec18972ebee9e2485
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1.7 KiB
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39 lines
1.7 KiB
ReStructuredText
Internal Session Cache
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======================
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The ``redfish`` hardware type, and derived interfaces, utilizes a built-in
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session cache which prevents Ironic from re-authenticating every time
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Ironic attempts to connect to the BMC for any reason.
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This consists of cached connectors objects which are used and tracked by
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a unique consideration of ``redfish_username``, ``redfish_password``,
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``redfish_verify_ca``, and finally ``redfish_address``. Changing any one
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of those values will trigger a new session to be created.
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The ``redfish_system_id`` value is explicitly not considered as Redfish
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has a model of use of one BMC to many systems, which is also a model
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Ironic supports.
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The session cache default size is ``1000`` sessions per conductor.
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If you are operating a deployment with a larger number of Redfish
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BMCs, it is advised that you do appropriately tune that number.
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This can be tuned via the API service configuration file,
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``[redfish]connection_cache_size``.
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Session Cache Expiration
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~~~~~~~~~~~~~~~~~~~~~~~~
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By default, sessions remain cached for as long as possible in
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memory, as long as they have not experienced an authentication,
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connection, or other unexplained error.
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Under normal circumstances, the sessions will only be rolled out
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of the cache in order of oldest first when the cache becomes full.
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There is no time based expiration to entries in the session cache.
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Of course, the cache is only in memory, and restarting the
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``ironic-conductor`` will also cause the cache to be rebuilt
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from scratch. If this is due to any persistent connectivity issue,
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this may be sign of an unexpected condition, and please consider
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contacting the Ironic developer community for assistance.
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