Kubernetes Scheduler 源码阅读

https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/api/v1/types.go#L31

  {
      "kind" : "Policy",
      "apiVersion" : "v1",
      "extenders" : [
          {
              "urlPrefix": "http://127.0.0.1:3456/scheduler",
              "filterVerb": "predicates",
              "enableHttps": false,
              "nodeCacheCapable": false,
              "managedResources": [{
                  "name": "tencent.com/vcuda-core",
                  "ignoredByScheduler": false
              }, {
                  "name": "tencent.com/vcuda-memory",
                  "ignoredByScheduler": false
              }]
          }
      ],
      "hardPodAffinitySymmetricWeight" : 10,
      "alwaysCheckAllPredicates" : false
  }

谁调用 MakeNextPod, 然后调 schedulerOne? scheduling_queue.go:815] About to try and schedule pod default/engine-static-feature-db-worker-p4-3-0 https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/internal/queue/scheduling_queue.go#L811

scheduler.go:456] Attempting to schedule pod: default/engine-static-feature-db-worker-p4-3-0 https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/scheduler.go#L442

sched.schedule https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/scheduler.go#L283

• sched.config.Algorithm.Schedule(pod, sched.config.NodeLister)

  • scheduler.algorithm = NewGenericScheduler -> genericScheduler

  • sched.config.NodeLister = core node lister

    • genericScheduler.Schedule

      • genericScheduler.findNodesThatFit

        • genericScheduler.predicates(自带 predicates) len == 0 -> all

        • 否则

          • numNodesToFind = numFeasibleNodesToFind 目标个数，到这个数就不找了

          • checkNode 塞到 ParallelizeUntil -> 16 个 worker 处理所有 node

            • podFitsOnNode

              • all predicates: https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/algorithm/predicates/predicates.go#L143, 包括 resources

        • extenders(目前是 HTTP Extenders: https://sourcegraph.com/github.com/kubernetes/[email protected]/-/blob/pkg/scheduler/core/extender.go#L42:6)

          • h.managedResources.Len() == 0 { return true } && if h.hasManagedResources { return true }
          • extender.IsIgnorable() 当 http extender 返回 err, 如果 ignorable, 就 ignore, 否则返回空列表

provider: GetAlgorithmProvider -> CreateFromKeys -> NewGenericScheduler policy: CreateFromConfig -> CreateFromKeys -> core.NewGenericScheduler

policy(file,cm)读取文件内容方式不同

• initPolicyFromFile(source.Policy.File.Path, policy);
• initPolicyFromConfigMap(client, source.Policy.ConfigMap, policy);

policy schedulerapi.ExtenderConfig:

  struct {
      URLPrefix string
      FilterVerb string
      PreemptVerb string
      PrioritizeVerb string
      Weight int
      BindVerb string
      EnableHTTPS bool
      TLSConfig *ExtenderTLSConfig
      HTTPTimeout Duration
      NodeCacheCapable bool
      ManagedResources []ExtenderManagedResource
      Ignorable bool
  }

scheduler.algorithm = NewGenericScheduler -> genericScheduler

CreateFromConfig:

• if policy.Predicates == nil

  • klog.V(2).Infof("Using predicates from algorithm provider '%v'", DefaultProvider)

• if policy.Priorities == nil {

  • klog.V(2).Infof("Using priorities from algorithm provider '%v'", DefaultProvider)

• for ii := range policy.ExtenderConfigs {

  • klog.V(2).Infof("Creating extender with config %+v", policy.ExtenderConfigs[ii])
  • extender, err := core.NewHTTPExtender(&policy.ExtenderConfigs[ii])

  • if !extender.IsIgnorable() :

    • 有一个 ignorable 列表，在 extender 列表最后，
    • 有一个 ignoredExtendedResources 列表

  • for _, r := range policy.ExtenderConfigs[ii].ManagedResources {

    • if r.IgnoredByScheduler {

      • ignoredExtendedResources.Insert(string(r.Name))

默认： predicates 'map[CheckNodeUnschedulable:{} CheckVolumeBinding:{} GeneralPredicates:{} MatchInterPodAffinity:{} MaxAzureDiskVolumeCount:{} MaxCSIVolumeCountPred:{} MaxEBSVolumeCount:{} MaxGCEPDVolumeCount:{} NoDiskConflict:{} NoVolumeZoneConflict:{} PodToleratesNodeTaints:{}]' and priority functions 'map[BalancedResourceAllocation:{} ImageLocalityPriority:{} InterPodAffinityPriority:{} LeastRequestedPriority:{} NodeAffinityPriority:{} NodePreferAvoidPodsPriority:{} SelectorSpreadPriority:{} TaintTolerationPriority:{}]'