This change will leverage the new PreFilterResult
to reduce down the list of eligible nodes for pod
using Bound Local PVs during PreFilter stage so
that only the node(s) which local PV node affinity
matches will be cosnidered in subsequent scheduling
stages.
Today, the NodeAffinity check is done during Filter
which means all nodes will be considered even though
there may be a large number of nodes that are not
eligible due to not matching the pod's bound local
PV(s)' node affinity requirement. Here we can
reduce down the node list in PreFilter to ensure that
during Filter we are only considering the reduced
list and thus can provide a more clear message to
users when node(s) are not available for scheduling
since the list only contains relevant nodes.
If error is encountered (e.g. PV cache read error) or
if node list reduction cannot be done (e.g. pod uses
no local PVs), then we will still proceed to consider
all nodes for the rest of scheduling stages.
Signed-off-by: Yibo Zhuang <yibzhuang@gmail.com>
380c7f248e