DONE:
1. refactor all predicates: predicates return fitOrNot(bool) and error(Error) in which the latter is of type
PredicateFailureError or InsufficientResourceError. (For violation of either MaxEBSVolumeCount or
MaxGCEPDVolumeCount, returns one same error type as ErrMaxVolumeCountExceeded)
2. GeneralPredicates() is a predicate function, which includes serveral other predicate functions (PodFitsResource,
PodFitsHost, PodFitsHostPort). It is registered as one of the predicates in DefaultAlgorithmProvider, and
is also called in canAdmitPod() in Kubelet and should be called by other components (like rescheduler, etc)
if necessary. See discussion in issue #12744
3. remove podNumber check from GeneralPredicates
4. HostName is now verified in Kubelet's canAdminPod(). add TestHostNameConflicts in kubelet_test.go
5. add getNodeAnyWay() method in Kubelet to get node information in standaloneMode
TODO:
1. determine which predicates should be included in GeneralPredicates()
2. separate GeneralPredicates() into:
a. GeneralPredicatesEvictPod() and
b. GeneralPredicatesNotEvictPod()
3. DaemonSet should use GeneralPredicates()
Instead of sorting hosts by score, find max score and choose one of
the hosts with max score directly. Saves a little time on sorting and
avoids extra copying of HostPriorityList entries.
Test had to be updated as one of the test cases relied on having a
stable order from pre-sorting.
To improve the throughput of current scheduler, we can do
a simple optimization by calcluating priorities in parallel.
This doubles the throughput of density test, which has the default
config with 3 priority funcs (the spreading one does not actually
consume any computation time). It matches the expectation.
The "Combined requested resources" message becomes excessive as
the cluster fills up, drop it down to V(2)
Put an explicit V(2) on the only other scheduler Infof call that didn't
have V specified already.
A lot of packages use StringSet, but they don't use anything else from
the util package. Moving StringSet into another package will shrink
their dependency trees significantly.
Having no nodes in the cluster is unusual and is likely a test
environment, and when a pod is deleted there is no need to log
information about our inability to schedule it.
