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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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Internal Session Cache
The redfish hardware type, and derived interfaces,
utilizes a built-in session cache which prevents Ironic from
re-authenticating every time Ironic attempts to connect to the BMC for
any reason.
This consists of cached connectors objects which are used and tracked
by a unique consideration of redfish_username,
redfish_password, redfish_verify_ca, and
finally redfish_address. Changing any one of those values
will trigger a new session to be created. The
redfish_system_id value is explicitly not considered as
Redfish has a model of use of one BMC to many systems, which is also a
model Ironic supports.
The session cache default size is 1000 sessions per
conductor. If you are operating a deployment with a larger number of
Redfish BMCs, it is advised that you do appropriately tune that number.
This can be tuned via the API service configuration file,
[redfish]connection_cache_size.
Session Cache Expiration
By default, sessions remain cached for as long as possible in memory, as long as they have not experienced an authentication, connection, or other unexplained error.
Under normal circumstances, the sessions will only be rolled out of the cache in order of oldest first when the cache becomes full. There is no time based expiration to entries in the session cache.
Of course, the cache is only in memory, and restarting the
ironic-conductor will also cause the cache to be rebuilt
from scratch. If this is due to any persistent connectivity issue, this
may be sign of an unexpected condition, and please consider contacting
the Ironic developer community for assistance.