In blueprint [1], we approved to allow set weights multiplier on host aggregates to have more flexibility when scheduling.

In order to make weigher can get the metadata info, we propose to add a new parameter "host_state" in weight_multiplier method [2],

just like what we current do in filter host_passes [3].

That means if you implements the custom weigher, you should change your weigher to accept a host_state.

Any thoughts or feedback are welcome, thanks! : )