Migrate scheduler api types to sized integers #82283

ahmad-diaa · 2019-09-03T16:14:48Z

What type of PR is this?
/kind bug

What this PR does / why we need it:
Migrating int types to fixed sizes in https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/api/types.go and https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/api/v1/types.go. Having different integer fields led to difficulty in encoding and decoding between both types.

Which issue(s) this PR fixes:

Fixes #82138

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

k8s-ci-robot · 2019-09-03T16:14:56Z

Hi @ahmad-diaa. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

draveness

/ok-to-test

draveness · 2019-09-03T16:59:36Z

pkg/scheduler/api/v1/types.go

@@ -137,17 +137,17 @@ type RequestedToCapacityRatioArguments struct {
 // UtilizationShapePoint represents single point of priority function shape.
 type UtilizationShapePoint struct {
 	// Utilization (x axis). Valid values are 0 to 100. Fully utilized node maps to 100.
-	Utilization int `json:"utilization"`
+	Utilization int8 `json:"utilization"`


I don't think we should change it to int8 which is not common in the k/k

$ ag int8 pkg pkg/controller/daemon/daemon_controller_test.go 580: for pass := uint8(0); expectedLimit <= podControl.FakePodControl.CreateLimit; pass++ { pkg/controller/job/job_controller_test.go 360: for pass := uint8(0); expectedLimit <= tc.podLimit; pass++ { pkg/controller/replicaset/replica_set_test.go 269: for pass := uint8(0); expectedLimit <= fakePodControl.CreateLimit; pass++ { pkg/kubelet/apis/podresources/v1alpha1/api.pb.go 398: dAtA[i] = uint8(uint64(l)&0x7f | 0x80) 402: dAtA[i] = uint8(l) 412: dAtA[offset] = uint8(v&0x7f | 0x80) 416: dAtA[offset] = uint8(v) pkg/kubelet/apis/pluginregistration/v1/api.pb.go 309: dAtA[i] = uint8(uint64(l)&0x7f | 0x80) 313: dAtA[i] = uint8(l) 393: dAtA[offset] = uint8(v&0x7f | 0x80) 397: dAtA[offset] = uint8(v) pkg/kubelet/apis/pluginregistration/v1alpha1/api.pb.go 560: dAtA[offset] = uint8(v&0x7f | 0x80) 564: dAtA[offset] = uint8(v) pkg/kubelet/apis/pluginregistration/v1beta1/api.pb.go 560: dAtA[offset] = uint8(v&0x7f | 0x80) 564: dAtA[offset] = uint8(v) pkg/kubelet/apis/deviceplugin/v1alpha/api.pb.go 1169: dAtA[offset] = uint8(v&0x7f | 0x80) 1173: dAtA[offset] = uint8(v) pkg/kubelet/apis/deviceplugin/v1beta1/api.pb.go 1857: dAtA[offset] = uint8(v&0x7f | 0x80) 1861: dAtA[offset] = uint8(v) pkg/kubelet/pluginmanager/pluginwatcher/example_plugin_apis/v1beta2/api.pb.go 324: dAtA[offset] = uint8(v&0x7f | 0x80) 328: dAtA[offset] = uint8(v) pkg/kubelet/pluginmanager/pluginwatcher/example_plugin_apis/v1beta1/api.pb.go 323: dAtA[offset] = uint8(v&0x7f | 0x80) 327: dAtA[offset] = uint8(v) pkg/registry/core/service/allocator/utils.go 31:var bitCounts = []int8{ pkg/kubectl/cmd/get/sorter.go 174: case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: 176: case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: 211: case uint8: 212: if jtype, ok := j.Interface().(uint8); ok { 227: case int8: 228: if jtype, ok := j.Interface().(int8); ok {

Do you think it's better to use int32 like other fields even if it's bounded by (0-100)?

I agree with @draveness, let's prefer int32 and int64.

pkg/scheduler/factory/plugins_test.go

alculquicondor · 2019-09-03T19:13:33Z

pkg/scheduler/api/types.go

@@ -34,7 +35,7 @@ const (
 	// MaxPriority defines the max priority value.
 	MaxPriority = 10
 	// MaxWeight defines the max weight value.
-	MaxWeight = MaxInt / MaxPriority
+	MaxWeight = int32(math.MaxInt32 / MaxPriority)


side note... why are we exporting a MaxInt constant? Maybe we should consider removing it. Can you open an issue for it? cc @ahg-g

Maybe that's because MaxInt is not exported by the math package and it's used by plugins_test.go. Is that what you were referring to?

exporting because of a test is a bad reason, specially in an API package.

MaxWeight could used by the user of kubernetes which could help them to limit the range of weight in extender or prioritiy functions.

@draveness unexporting MaxInt does not have anything to do with keeping MaxWeight Exported. Am I missing anything?

We should ask if we can change the values, I don't know whether or not this is considered part of the v1 API.

We should ask if we can change the values, I don't know whether or not this is considered part of the v1 API.

Previously, a config file could specify a weight up to 9,223,372,036,854,775,807 / 10, right? This change limits weights to 2,147,483,647 / 10. Is there a reason not to switch to sized ints at int64 for compatibility?

No, we can do that. I get your point now on what we should be preserving.

alculquicondor · 2019-09-03T19:16:52Z

pkg/scheduler/api/v1/types.go

@@ -137,17 +137,17 @@ type RequestedToCapacityRatioArguments struct {
 // UtilizationShapePoint represents single point of priority function shape.
 type UtilizationShapePoint struct {
 	// Utilization (x axis). Valid values are 0 to 100. Fully utilized node maps to 100.
-	Utilization int `json:"utilization"`
+	Utilization int8 `json:"utilization"`


I agree with @draveness, let's prefer int32 and int64.

alculquicondor · 2019-09-03T19:20:25Z

pkg/scheduler/algorithm/scheduler_interface.go

@@ -39,7 +39,7 @@ type SchedulerExtender interface {
 	// Prioritize based on extender-implemented priority functions. The returned scores & weight
 	// are used to compute the weighted score for an extender. The weighted scores are added to
 	// the scores computed  by Kubernetes scheduler. The total scores are used to do the host selection.
-	Prioritize(pod *v1.Pod, nodes []*v1.Node) (hostPriorities *schedulerapi.HostPriorityList, weight int, err error)
+	Prioritize(pod *v1.Pod, nodes []*v1.Node) (hostPriorities *schedulerapi.HostPriorityList, weight int32, err error)


I'm ok with leaving non-API types as int. It is guaranteed that int is at least 32 bits.

alculquicondor · 2019-09-03T19:29:38Z

pkg/scheduler/api/types.go

@@ -86,7 +87,7 @@ type PriorityPolicy struct {
 	Name string
 	// The numeric multiplier for the node scores that the priority function generates
 	// The weight should be a positive integer
-	Weight int
+	Weight int32


I would say this should be int64, as there is the possibility that some users might be relying on big numbers.

I used the the framework scoring step as a reference:

kubernetes/pkg/scheduler/apis/config/types.go

Lines 196 to 201 in 1855901

type Plugin struct {

// Name defines the name of plugin

Name string

// Weight defines the weight of plugin, only used for Score plugins.

Weight int32

}

Also, don't you think that int32 would be enough to represent a big range of numbers?

I don't have a strong opinion on this. Let's see what other reviewers think.

int32 should be good enough.

unless there's a strong reason not to, keeping int64 for compatibility with all possible existing config files is preferable

pkg/scheduler/factory/plugins_test.go

alculquicondor · 2019-09-04T12:43:07Z

pkg/scheduler/algorithm/priorities/types.go

@@ -50,7 +50,7 @@ type PriorityConfig struct {
 	// TODO: Remove it after migrating all functions to
 	// Map-Reduce pattern.
 	Function PriorityFunction
-	Weight   int
+	Weight   int32


can we leave this one as int too?

alculquicondor · 2019-09-04T18:24:45Z

pkg/scheduler/core/generic_scheduler.go

@@ -1087,7 +1087,7 @@ func selectVictimsOnNode(
 	fitPredicates map[string]predicates.FitPredicate,
 	queue internalqueue.SchedulingQueue,
 	pdbs []*policy.PodDisruptionBudget,
-) ([]*v1.Pod, int, bool) {
+) ([]*v1.Pod, int32, bool) {


is this change necessary? I prefer we just change the API

It wouldn't be safe to return an int then cast it to int32

kubernetes/pkg/scheduler/core/generic_scheduler.go

Lines 1014 to 1021 in 84fe3db

pods, numPDBViolations, fits := selectVictimsOnNode(pod, metaCopy, nodeNameToInfo[nodeName], fitPredicates, queue, pdbs)

if fits {

resultLock.Lock()

victims := schedulerapi.Victims{

Pods: pods,

NumPDBViolations: numPDBViolations,

}

nodeToVictims[potentialNodes[i]] = &victims

should we change schedulerapi.Victims.NumPDBViolations to int64 then?

+1 to Aldo's suggestion because even this current code is susceptible to overflow at https://github.com/kubernetes/kubernetes/pull/82283/files#diff-c237cdd9e4cb201118ca380732d7f361R1149.

I suggest you just cast to int32 at line 1018, and keep everything else the same.

changing NumPDBViolations to int64 will solve this issue.

k82cn · 2019-09-05T07:14:53Z

@ahmad-diaa , would you help to send an email to api-machinery group on whether we should keep backward compatibility in code level? for example, the user have to update his code if he import those APIs.

k82cn · 2019-09-05T07:15:18Z

similar comments on Lt/Gt features

/cc @wgliang

ahg-g · 2019-09-06T17:09:07Z

@liggitt can you please provide guidance here? we are trying to move to sized integers in this old API, we are wondering how we should do that given that this is already a v1 API, can we just change types? what about values of constants, are we allowed to change them?

liggitt · 2019-09-06T17:27:05Z

@liggitt can you please provide guidance here? we are trying to move to sized integers in this old API, we are wondering how we should do that given that this is already a v1 API, can we just change types?

The important thing is to be able to continue deserializing config files you previously accepted. The safest way to do that is to switch unsized integers to int64.

json/yaml integers can't reliable serialize beyond 52 bits of precision (c.f. #17095), so someone using the highest possible int64 values could run into trouble with other json libraries, but that's less of a concern with config files consumed by a single binary than for REST APIs consumed by lots of clients implemented in lots of languages.

liggitt · 2019-09-06T17:29:52Z

The APIs we guarantee compatibility on are the REST APIs, config files, CLI flags, and persisted data. We do not guarantee go struct/interface/method compatibility release to release.

This PR is changing code inside the kubernetes/kubernetes repo that is not published for consumption as a go library, which is fine.

For repos we publish as libraries (things underneath the staging directory) kubernetes/publishing-bot#196 is investigating adding support for publishing each kubernetes release under a new import path, so you could explicitly choose to switch to using (for example) k8s.io/kube-scheduler/v16

ahg-g · 2019-09-06T17:44:24Z

The APIs we guarantee compatibility on are the REST APIs, config files, CLI flags, and persisted data. We do not guarantee go struct/interface/method compatibility release to release.

This PR is changing code inside the kubernetes/kubernetes repo that is not published for consumption as a go library, which is fine.

For repos we publish as libraries (things underneath the staging directory) kubernetes/publishing-bot#196 is investigating adding support for publishing each kubernetes release under a new import path, so you could explicitly choose to switch to using (for example) k8s.io/kube-scheduler/v16

if I understand correctly, this implies that we are allowed to change (or even remove) the constants we define in https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/api/types.go#L27-L41 (those aren't even published under the versioned type: https://github.com/kubernetes/kubernetes/blob/master/pkg/scheduler/api/v1/types.go).

ahmad-diaa · 2019-09-06T22:43:29Z

pkg/scheduler/factory/plugins.go

@@ -385,7 +385,7 @@ func RegisterCustomPriorityFunction(policy schedulerapi.PriorityPolicy) string {
 						policy.Argument.LabelPreference.Presence,
 					)
 				},
-				Weight: policy.Weight,
+				Weight: int(policy.Weight),


unless there's a strong reason not to, keeping int64 for compatibility with all possible existing config files is preferable

@ahg-g @liggitt @alculquicondor I think this would be a reason to have PriorityPolicy.Weight as int32 and not int64, otherwise we would change the type of PriorityConfigFactory.Weight to int64. What do you think?

k82cn · 2019-09-07T05:27:46Z

The APIs we guarantee compatibility on are the REST APIs, config files, CLI flags, and persisted data. We do not guarantee go struct/interface/method compatibility release to release.

Great to know that, that'll be easier for us to refine the code :)

alculquicondor · 2019-09-09T14:28:03Z

pkg/scheduler/algorithm/priorities/reduce.go

@@ -42,7 +42,7 @@ func NormalizeReduce(maxPriority int, reverse bool) PriorityReduceFunction {
 		if maxCount == 0 {
 			if reverse {
 				for i := range result {
-					result[i].Score = maxPriority
+					result[i].Score = int64(maxPriority)


maybe maxPriority should be int64, as it comes from a constant of an int64 value.

Do you mean changing the type passed to NormalizeReduce?

alculquicondor · 2019-09-09T14:28:57Z

pkg/scheduler/algorithm/priorities/selector_spreading.go

@@ -80,15 +80,15 @@ func (s *SelectorSpread) CalculateSpreadPriorityMap(pod *v1.Pod, meta interface{
 	if len(selectors) == 0 {
 		return schedulerapi.HostPriority{
 			Host:  node.Name,
-			Score: int(0),
+			Score: int64(0),


doesn't this just work as Score: 0?

alculquicondor · 2019-09-09T14:46:23Z

pkg/scheduler/algorithm/priorities/selector_spreading.go

@@ -261,7 +261,7 @@ func (s *ServiceAntiAffinity) CalculateAntiAffinityPriorityReduce(pod *v1.Pod, m
 		label, ok := labelNodesStatus[hostPriority.Host]
 		if !ok {
 			result[i].Host = hostPriority.Host
-			result[i].Score = int(0)
+			result[i].Score = int64(0)


result[i].Score = 0 should work

alculquicondor · 2019-09-09T14:54:27Z

pkg/scheduler/algorithm/priorities/types.go

@@ -50,7 +50,7 @@ type PriorityConfig struct {
 	// TODO: Remove it after migrating all functions to
 	// Map-Reduce pattern.
 	Function PriorityFunction
-	Weight   int
+	Weight   int64


I think this can safely be int. Even though the API type is int64, it's value is validated to be less than MaxWeight before assigning it here.

For doing so, we should keep MaxWeight as MaxInt/MaxPriority and avoid changing it to MaxInt64/MaxPriority .. right?

Also should the same check (to validate that the weight is less than MaxWeight) be added to ExtenderConfigs weight in

kubernetes/pkg/scheduler/api/validation/validation.go

Line 45 in 35cf6b6

if len(extender.PrioritizeVerb) > 0 && extender.Weight <= 0 {

like the one done in:

kubernetes/pkg/scheduler/api/validation/validation.go

Line 37 in 35cf6b6

if priority.Weight <= 0 || priority.Weight >= schedulerapi.MaxWeight {

I read that wrong. MaxWeight could still be big. I was thinking of Maxpriority.

should it be kept as it is then?

alculquicondor · 2019-09-10T12:56:24Z

/lgtm
/retest

ahg-g · 2019-09-12T15:47:37Z

pkg/scheduler/api/types.go

 	// Score assigned to given utilization (y axis). Valid values are 0 to 10.
-	Score int
+	Score int32


sounds strange that we use int64 here, but int32 in another place below (line 345) for semantically a similar parameter.

That's because at this part values are constrained to (1-100) and (0-10). Do you still think it should be changed?

All of the other cases have the same constraint. So I think we can make all of them int64 or int32.

actually it is not, but still I prefer to make them consistent.

I take that back, I think we should move HostPriority outside the API because it does not belong there.

Should it be moved in another PR, I think this would be out of the scope of this PR.

Also, does that mean that it's ok to keep it as int32 here? or should it be changed to int64 for consistency?

I was just looking at the extender code, it turns out that HostPriorityList is the expected response to one of the extender calls, so we can't move it. This current PR is fine.

ahg-g · 2019-09-12T16:52:11Z

/lgtm
/approve

k8s-ci-robot · 2019-09-12T16:53:02Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahg-g, ahmad-diaa

The full list of commands accepted by this bot can be found here.

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ahmad-diaa · 2019-09-12T17:13:23Z

@ahg-g commits aren't squashed yet. squashing now.

alculquicondor · 2019-09-12T17:50:03Z

/lgtm

thanks for the squash

liggitt · 2019-09-12T19:11:38Z

/hold
temporary hold for a 1.16-blocking PR... I'll unhold by EOD

ahmad-diaa · 2019-09-12T19:51:48Z

/retest

liggitt · 2019-09-12T21:18:04Z

/hold cancel

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[scheduler cleanup phase 2]: Move users of factory.NewConfigFactory to scheduler.New #71859

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Unnecessarily Exported MaxInt in scheduler api types #82306

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migrate scheduler api types to sized integers

801cc54

ahmad-diaa force-pushed the fix-field-types-in-scheduler-api-types branch from ab2b20f to 801cc54 Compare September 12, 2019 17:14

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REQUEST: New membership for Ahmad Diaa kubernetes/org#1195

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6 tasks

	type Plugin struct {
	// Name defines the name of plugin
	Name string
	// Weight defines the weight of plugin, only used for Score plugins.
	Weight int32
	}

	pods, numPDBViolations, fits := selectVictimsOnNode(pod, metaCopy, nodeNameToInfo[nodeName], fitPredicates, queue, pdbs)
	if fits {
	resultLock.Lock()
	victims := schedulerapi.Victims{
	Pods: pods,
	NumPDBViolations: numPDBViolations,
	}
	nodeToVictims[potentialNodes[i]] = &victims

Migrate scheduler api types to sized integers #82283

Migrate scheduler api types to sized integers #82283

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k82cn commented Sep 5, 2019

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ahg-g commented Sep 12, 2019

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