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Diffstat (limited to 'doc/source/admin/drivers/redfish.rst')
| -rw-r--r-- | doc/source/admin/drivers/redfish.rst | 50 |
1 files changed, 49 insertions, 1 deletions
diff --git a/doc/source/admin/drivers/redfish.rst b/doc/source/admin/drivers/redfish.rst index f4eab73eb..363eb7b49 100644 --- a/doc/source/admin/drivers/redfish.rst +++ b/doc/source/admin/drivers/redfish.rst @@ -87,8 +87,18 @@ field: The "auto" mode first tries "session" and falls back to "basic" if session authentication is not supported by the Redfish BMC. Default is set in ironic config - as ``[redfish]auth_type``. + as ``[redfish]auth_type``. Most operators should not + need to leverage this setting. Session based + authentication should generally be used in most + cases as it prevents re-authentication every time + a background task checks in with the BMC. +.. note:: + The ``redfish_address``, ``redfish_username``, ``redfish_password``, + and ``redfish_verify_ca`` fields, if changed, will trigger a new session + to be establsihed and cached with the BMC. The ``redfish_auth_type`` field + will only be used for the creation of a new cached session, or should + one be rejected by the BMC. The ``baremetal node create`` command can be used to enroll a node with the ``redfish`` driver. For example: @@ -592,6 +602,44 @@ Eject Virtual Media "boot_device (optional)", "body", "string", "Type of the device to eject (all devices by default)" +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. + .. _Redfish: http://redfish.dmtf.org/ .. _Sushy: https://opendev.org/openstack/sushy .. _TLS: https://en.wikipedia.org/wiki/Transport_Layer_Security |