when DefaultPodTopologySpread feature is enabled
If SelectorSpreadPriority is in use, PodTopologySpread gets inevitably enabled.
When only EvenPodsSpreadPriority is in use, PodTopologySpread is configured without system defaults.
Change-Id: I2389a585cd8ad0bd35b0d2acae1665cd46908b3e
For separation of concerns. Also make the producers receive the
existing configuration so they can take decisions based on them.
Change-Id: Id5db5588aabb90e7b8f087bd3f3c967e86dc4acc
Previously, separate interfaces were defined for Reserve and Unreserve
plugins. However, in nearly all cases, a plugin that allocates a
resource using Reserve will likely want to register itself for Unreserve
as well in order to free the allocated resource at the end of a failed
scheduling/binding cycle. Having separate plugins for Reserve and
Unreserve also adds unnecessary config toil. To that end, this patch
aims to merge the two plugins into a single interface called a
ReservePlugin that requires implementing both the Reserve and Unreserve
methods.
