Spec Lite: Deprecate store_capabilities_update_min_interval

Spec Lite: Deprecate store_capabilities_update_min_interval

project:

glance_store

problem:

The configuration option store_capabilities_update_min_interval is confusing because no existing stores implement the StoreCapability.update_capabilities() method. This has come up in the context of nfs being used for the filesystem backend. If nfs is not ready for writing when the glance api starts, glance will mark the filesystem as not writeable. Operators have tried to get around this problem by setting a non-zero positive value for this option only to find that it doesn’t work.

solution:

Use oslo.config to mark the option as ‘deprecated’ with an appropriate note. Option will be deprecated in Rocky for removal in ‘S’.

alternatives:

An alternative would be to rewrite the option help text to make it clear that there is no current store for which the option is actionable, but that a framework is in place through which dynamic capability determination could be implemented. Currently a debug level message to this effect is logged on store startup although it is not obvious that the message is related to the ineffectiveness of setting the store_capabilities_update_min_interval option. The message is: “Store %s doesn’t support updating dynamic storage capabilities. Please overwrite ‘update_capabilities’ method of the store to implement updating logics if needed.” (This message is logged independently of setting the option.)

The advantage to this approach is that the framework would be available to someone who wanted to implement dynamic updates for a store, and the option would not have to be re-introduced.

impacts:

None

timeline:

Rocky milestone 2

assignee:

rosmaita

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