Add scheduler overprovision for new actions before namespace throttling (apache#5284)

* initial attempt

* tests

* fix tests

* enable throttling when last capacity used in overprovisioning

* add case to correctly disable namespace throttling when namespace overprovisioning has space

* feedback

Co-authored-by: Brendan Doyle <[email protected]>

Author: 2 people

core/scheduler/src/main/resources/application.conf

@@ -79,6 +79,8 @@ whisk {
       stale-threshold = "100 milliseconds"
       check-interval = "100 milliseconds"
       drop-interval = "10 seconds"
+      allow-over-provision-before-throttle = false
+      namespace-over-provision-before-throttle-ratio = 1.5
     }
     queue {
       idle-grace = "20 seconds"

core/scheduler/src/main/scala/org/apache/openwhisk/core/scheduler/Scheduler.scala

@@ -421,4 +421,8 @@ object SchedulerStates extends DefaultJsonProtocol {
   def parse(states: String) = Try(serdes.read(states.parseJson))
 }
 
-case class SchedulingConfig(staleThreshold: FiniteDuration, checkInterval: FiniteDuration, dropInterval: FiniteDuration)
+case class SchedulingConfig(staleThreshold: FiniteDuration,
+                            checkInterval: FiniteDuration,
+                            dropInterval: FiniteDuration,
+                            allowOverProvisionBeforeThrottle: Boolean,
+                            namespaceOverProvisionBeforeThrottleRatio: Double)

core/scheduler/src/main/scala/org/apache/openwhisk/core/scheduler/queue/SchedulingDecisionMaker.scala

@@ -70,7 +70,17 @@ class SchedulingDecisionMaker(
         case _        => Future.successful(DecisionResults(Pausing, 0))
       }
     } else {
-      val capacity = limit - existingContainerCountInNs - inProgressContainerCountInNs
+      val capacity = if (schedulingConfig.allowOverProvisionBeforeThrottle && totalContainers == 0) {
+        // if space available within the over provision ratio amount above namespace limit, create one container for new
+        // action so namespace traffic can attempt to re-balance without blocking entire action
+        if ((ceiling(limit * schedulingConfig.namespaceOverProvisionBeforeThrottleRatio) - existingContainerCountInNs - inProgressContainerCountInNs) > 0) {
+          1
+        } else {
+          0
+        }
+      } else {
+        limit - existingContainerCountInNs - inProgressContainerCountInNs
+      }
       if (capacity <= 0) {
         stateName match {
 
@@ -79,12 +89,15 @@ class SchedulingDecisionMaker(
            *
            * However, if the container exists(totalContainers != 0), the activation is not treated as a failure and the activation is delivered to the container.
            */
-          case Running =>
+          case Running
+              if !schedulingConfig.allowOverProvisionBeforeThrottle || (schedulingConfig.allowOverProvisionBeforeThrottle && ceiling(
+                limit * schedulingConfig.namespaceOverProvisionBeforeThrottleRatio) - existingContainerCountInNs - inProgressContainerCountInNs <= 0) =>
             logging.info(
               this,
               s"there is no capacity activations will be dropped or throttled, (availableMsg: $availableMsg totalContainers: $totalContainers, limit: $limit, namespaceContainers: ${existingContainerCountInNs}, namespaceInProgressContainer: ${inProgressContainerCountInNs}) [$invocationNamespace:$action]")
             Future.successful(DecisionResults(EnableNamespaceThrottling(dropMsg = totalContainers == 0), 0))
-
+          case NamespaceThrottled if schedulingConfig.allowOverProvisionBeforeThrottle && ceiling(limit * schedulingConfig.namespaceOverProvisionBeforeThrottleRatio) - existingContainerCountInNs - inProgressContainerCountInNs > 0 =>
+            Future.successful(DecisionResults(DisableNamespaceThrottling, 0))
           // do nothing
           case _ =>
             // no need to print any messages if the state is already NamespaceThrottled

tests/src/test/scala/org/apache/openwhisk/core/scheduler/queue/test/MemoryQueueTestsFixture.scala

@@ -86,7 +86,7 @@ class MemoryQueueTestsFixture
   val testNamespace = "test-namespace"
   val testAction = "test-action"
 
-  val schedulingConfig = SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds)
+  val schedulingConfig = SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, false, 1.5)
 
   val fqn = FullyQualifiedEntityName(EntityPath(testNamespace), EntityName(testAction), Some(SemVer(0, 0, 1)))
   val revision = DocRevision("1-testRev")

tests/src/test/scala/org/apache/openwhisk/core/scheduler/queue/test/SchedulingDecisionMakerTests.scala

@@ -47,7 +47,7 @@ class SchedulingDecisionMakerTests
   val testAction = "test-action"
   val action = FullyQualifiedEntityName(EntityPath(testNamespace), EntityName(testAction), Some(SemVer(0, 0, 1)))
 
-  val schedulingConfig = SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds)
+  val schedulingConfig = SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, false, 1.5)
 
   it should "decide pausing when the limit is less than equal to 0" in {
     val decisionMaker = system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfig))
@@ -149,7 +149,7 @@ class SchedulingDecisionMakerTests
     }
   }
 
-  it should "enable namespace throttling with dropping msg when there is not enough capacity and no container" in {
+  it should "enable namespace throttling with dropping msg when there is not enough capacity, no container, and namespace over-provision disabled" in {
     val decisionMaker = system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfig))
     val testProbe = TestProbe()
 
@@ -173,7 +173,7 @@ class SchedulingDecisionMakerTests
     testProbe.expectMsg(DecisionResults(EnableNamespaceThrottling(dropMsg = true), 0))
   }
 
-  it should "enable namespace throttling without dropping msg when there is not enough capacity but are some containers" in {
+  it should "enable namespace throttling without dropping msg when there is not enough capacity but are some containers and namespace over-provision disabled" in {
     val decisionMaker = system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfig))
     val testProbe = TestProbe()
 
@@ -197,7 +197,142 @@ class SchedulingDecisionMakerTests
     testProbe.expectMsg(DecisionResults(EnableNamespaceThrottling(dropMsg = false), 0))
   }
 
-  it should "add an initial container if there is no any" in {
+  it should "add one container when there is no container, and namespace over-provision has capacity" in {
+    val schedulingConfigNamespaceOverProvisioning =
+      SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, true, 1.5)
+    val decisionMaker =
+      system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfigNamespaceOverProvisioning))
+    val testProbe = TestProbe()
+
+    val msg = QueueSnapshot(
+      initialized = false,
+      incomingMsgCount = new AtomicInteger(0),
+      currentMsgCount = 0,
+      existingContainerCount = 0, // there is no container for this action
+      inProgressContainerCount = 0,
+      staleActivationNum = 0,
+      existingContainerCountInNamespace = 1, // but there are already 2 containers in this namespace
+      inProgressContainerCountInNamespace = 1,
+      averageDuration = None,
+      limit = 2,
+      stateName = Running,
+      recipient = testProbe.ref)
+
+    decisionMaker ! msg
+
+    // this queue cannot create an initial container so enable throttling and drop messages.
+    testProbe.expectMsg(DecisionResults(AddInitialContainer, 1))
+  }
+
+  it should "enable namespace throttling with dropping msg when there is no container, and namespace over-provision has no capacity" in {
+    val schedulingConfigNamespaceOverProvisioning =
+      SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, true, 1.0)
+    val decisionMaker =
+      system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfigNamespaceOverProvisioning))
+    val testProbe = TestProbe()
+
+    val msg = QueueSnapshot(
+      initialized = true,
+      incomingMsgCount = new AtomicInteger(0),
+      currentMsgCount = 0,
+      existingContainerCount = 0, // there is no container for this action
+      inProgressContainerCount = 0,
+      staleActivationNum = 0,
+      existingContainerCountInNamespace = 1, // but there are already 2 containers in this namespace
+      inProgressContainerCountInNamespace = 1,
+      averageDuration = None,
+      limit = 2,
+      stateName = Running,
+      recipient = testProbe.ref)
+
+    decisionMaker ! msg
+
+    // this queue cannot create an initial container so enable throttling and drop messages.
+    testProbe.expectMsg(DecisionResults(EnableNamespaceThrottling(dropMsg = true), 0))
+  }
+
+  it should "disable namespace throttling when namespace over-provision has capacity again" in {
+    val schedulingConfigNamespaceOverProvisioning =
+      SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, true, 1.1)
+    val decisionMaker =
+      system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfigNamespaceOverProvisioning))
+    val testProbe = TestProbe()
+
+    val msg = QueueSnapshot(
+      initialized = true,
+      incomingMsgCount = new AtomicInteger(0),
+      currentMsgCount = 0,
+      existingContainerCount = 1, // there is one container for this action
+      inProgressContainerCount = 0,
+      staleActivationNum = 0,
+      existingContainerCountInNamespace = 1, // but there are already 2 containers in this namespace
+      inProgressContainerCountInNamespace = 1,
+      averageDuration = None,
+      limit = 2,
+      stateName = NamespaceThrottled,
+      recipient = testProbe.ref)
+
+    decisionMaker ! msg
+
+    // this queue cannot create an initial container so enable throttling and drop messages.
+    testProbe.expectMsg(DecisionResults(DisableNamespaceThrottling, 0))
+  }
+
+  it should "enable namespace throttling without dropping msg when there is a container, and namespace over-provision has no additional capacity" in {
+    val schedulingConfigNamespaceOverProvisioning =
+      SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, true, 1.0)
+    val decisionMaker =
+      system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfigNamespaceOverProvisioning))
+    val testProbe = TestProbe()
+
+    val msg = QueueSnapshot(
+      initialized = true,
+      incomingMsgCount = new AtomicInteger(0),
+      currentMsgCount = 0,
+      existingContainerCount = 1,
+      inProgressContainerCount = 0,
+      staleActivationNum = 0,
+      existingContainerCountInNamespace = 1, // but there are already 2 containers in this namespace
+      inProgressContainerCountInNamespace = 1,
+      averageDuration = None,
+      limit = 2,
+      stateName = Running,
+      recipient = testProbe.ref)
+
+    decisionMaker ! msg
+
+    // this queue cannot create an additional container so enable throttling and drop messages.
+    testProbe.expectMsg(DecisionResults(EnableNamespaceThrottling(dropMsg = false), 0))
+  }
+
+  it should "not enable namespace throttling when there is not enough capacity but are some containers and namespace over-provision is enabled with capacity" in {
+    val schedulingConfigNamespaceOverProvisioning =
+      SchedulingConfig(100.milliseconds, 100.milliseconds, 10.seconds, true, 1.5)
+    val decisionMaker =
+      system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfigNamespaceOverProvisioning))
+    val testProbe = TestProbe()
+
+    val msg = QueueSnapshot(
+      initialized = true,
+      incomingMsgCount = new AtomicInteger(0),
+      currentMsgCount = 0,
+      existingContainerCount = 1, // there are some containers for this action
+      inProgressContainerCount = 1,
+      staleActivationNum = 0,
+      existingContainerCountInNamespace = 2, // but there are already 2 containers in this namespace
+      inProgressContainerCountInNamespace = 2, // this value includes the count of this action as well.
+      averageDuration = None,
+      limit = 4,
+      stateName = Running,
+      recipient = testProbe.ref)
+
+    decisionMaker ! msg
+
+    // this queue cannot create more containers
+    testProbe.expectNoMessage()
+  }
+
+  it should "add an initial container if there is not any" in {
     val decisionMaker = system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfig))
     val testProbe = TestProbe()
 
@@ -219,6 +354,7 @@ class SchedulingDecisionMakerTests
 
     testProbe.expectMsg(DecisionResults(AddInitialContainer, 1))
   }
+
   it should "disable the namespace throttling with adding an initial container when there is no container" in {
     val decisionMaker = system.actorOf(SchedulingDecisionMaker.props(testNamespace, action, schedulingConfig))
     val testProbe = TestProbe()