X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/bfb9e29c250bcfb34a6b1813ca46953503ca05e6..60542dcecbffe14a43098d9e68ee6ae05868df1e:/lib/dispatchcloud/scheduler/run_queue.go

diff --git a/lib/dispatchcloud/scheduler/run_queue.go b/lib/dispatchcloud/scheduler/run_queue.go
index 1e5ac2e046..3505c3e064 100644
--- a/lib/dispatchcloud/scheduler/run_queue.go
+++ b/lib/dispatchcloud/scheduler/run_queue.go
@@ -16,13 +16,43 @@ import (
 var quietAfter503 = time.Minute
 
 func (sch *Scheduler) runQueue() {
+	running := sch.pool.Running()
+	unalloc := sch.pool.Unallocated()
+
+	totalInstances := 0
+	for _, n := range sch.pool.CountWorkers() {
+		totalInstances += n
+	}
+
 	unsorted, _ := sch.queue.Entries()
 	sorted := make([]container.QueueEnt, 0, len(unsorted))
 	for _, ent := range unsorted {
 		sorted = append(sorted, ent)
 	}
 	sort.Slice(sorted, func(i, j int) bool {
-		if pi, pj := sorted[i].Container.Priority, sorted[j].Container.Priority; pi != pj {
+		_, irunning := running[sorted[i].Container.UUID]
+		_, jrunning := running[sorted[j].Container.UUID]
+		if irunning != jrunning {
+			// Ensure the "tryrun" loop (see below) sees
+			// already-scheduled containers first, to
+			// ensure existing supervisor containers are
+			// properly counted before we decide whether
+			// we have room for new ones.
+			return irunning
+		}
+		ilocked := sorted[i].Container.State == arvados.ContainerStateLocked
+		jlocked := sorted[j].Container.State == arvados.ContainerStateLocked
+		if ilocked != jlocked {
+			// Give precedence to containers that we have
+			// already locked, even if higher-priority
+			// containers have since arrived in the
+			// queue. This avoids undesirable queue churn
+			// effects including extra lock/unlock cycles
+			// and bringing up new instances and quickly
+			// shutting them down to make room for
+			// different instance sizes.
+			return ilocked
+		} else if pi, pj := sorted[i].Container.Priority, sorted[j].Container.Priority; pi != pj {
 			return pi > pj
 		} else {
 			// When containers have identical priority,
@@ -34,9 +64,6 @@ func (sch *Scheduler) runQueue() {
 		}
 	})
 
-	running := sch.pool.Running()
-	unalloc := sch.pool.Unallocated()
-
 	if t := sch.client.Last503(); t.After(sch.last503time) {
 		// API has sent an HTTP 503 response since last time
 		// we checked. Use current #containers - 1 as
@@ -67,8 +94,54 @@ func (sch *Scheduler) runQueue() {
 	} else {
 		sch.mLast503Time.Set(float64(sch.last503time.Unix()))
 	}
+	if sch.maxInstances > 0 && sch.maxConcurrency > sch.maxInstances {
+		sch.maxConcurrency = sch.maxInstances
+	}
+	if sch.instancesWithinQuota > 0 && sch.instancesWithinQuota < totalInstances {
+		// Evidently it is possible to run this many
+		// instances, so raise our estimate.
+		sch.instancesWithinQuota = totalInstances
+	}
+	if sch.pool.AtQuota() {
+		// Consider current workload to be the maximum
+		// allowed, for the sake of reporting metrics and
+		// calculating max supervisors.
+		//
+		// Now that sch.maxConcurrency is set, we will only
+		// raise it past len(running) by 10%.  This helps
+		// avoid running an inappropriate number of
+		// supervisors when we reach the cloud-imposed quota
+		// (which may be based on # CPUs etc) long before the
+		// configured MaxInstances.
+		if sch.maxConcurrency == 0 || sch.maxConcurrency > totalInstances {
+			if totalInstances == 0 {
+				sch.maxConcurrency = 1
+			} else {
+				sch.maxConcurrency = totalInstances
+			}
+		}
+		sch.instancesWithinQuota = totalInstances
+	} else if sch.instancesWithinQuota > 0 && sch.maxConcurrency > sch.instancesWithinQuota+1 {
+		// Once we've hit a quota error and started tracking
+		// instancesWithinQuota (i.e., it's not zero), we
+		// avoid exceeding that known-working level by more
+		// than 1.
+		//
+		// If we don't do this, we risk entering a pattern of
+		// repeatedly locking several containers, hitting
+		// quota again, and unlocking them again each time the
+		// driver stops reporting AtQuota, which tends to use
+		// up the max lock/unlock cycles on the next few
+		// containers in the queue, and cause them to fail.
+		sch.maxConcurrency = sch.instancesWithinQuota + 1
+	}
 	sch.mMaxContainerConcurrency.Set(float64(sch.maxConcurrency))
 
+	maxSupervisors := int(float64(sch.maxConcurrency) * sch.supervisorFraction)
+	if maxSupervisors < 1 && sch.supervisorFraction > 0 && sch.maxConcurrency > 0 {
+		maxSupervisors = 1
+	}
+
 	sch.logger.WithFields(logrus.Fields{
 		"Containers":     len(sorted),
 		"Processes":      len(running),
@@ -76,7 +149,9 @@ func (sch *Scheduler) runQueue() {
 	}).Debug("runQueue")
 
 	dontstart := map[arvados.InstanceType]bool{}
-	var overquota []container.QueueEnt // entries that are unmappable because of worker pool quota
+	var atcapacity = map[string]bool{}    // ProviderTypes reported as AtCapacity during this runQueue() invocation
+	var overquota []container.QueueEnt    // entries that are unmappable because of worker pool quota
+	var overmaxsuper []container.QueueEnt // unmappable because max supervisors (these are not included in overquota)
 	var containerAllocatedWorkerBootingCount int
 
 	// trying is #containers running + #containers we're trying to
@@ -84,13 +159,22 @@ func (sch *Scheduler) runQueue() {
 	// reaches the dynamic maxConcurrency limit.
 	trying := len(running)
 
+	supervisors := 0
+
 tryrun:
-	for i, ctr := range sorted {
-		ctr, it := ctr.Container, ctr.InstanceType
+	for i, ent := range sorted {
+		ctr, it := ent.Container, ent.InstanceType
 		logger := sch.logger.WithFields(logrus.Fields{
 			"ContainerUUID": ctr.UUID,
 			"InstanceType":  it.Name,
 		})
+		if ctr.SchedulingParameters.Supervisor {
+			supervisors += 1
+			if maxSupervisors > 0 && supervisors > maxSupervisors {
+				overmaxsuper = append(overmaxsuper, sorted[i])
+				continue
+			}
+		}
 		if _, running := running[ctr.UUID]; running || ctr.Priority < 1 {
 			continue
 		}
@@ -98,8 +182,7 @@ tryrun:
 		case arvados.ContainerStateQueued:
 			if sch.maxConcurrency > 0 && trying >= sch.maxConcurrency {
 				logger.Tracef("not locking: already at maxConcurrency %d", sch.maxConcurrency)
-				overquota = sorted[i:]
-				break tryrun
+				continue
 			}
 			trying++
 			if unalloc[it] < 1 && sch.pool.AtQuota() {
@@ -107,6 +190,11 @@ tryrun:
 				overquota = sorted[i:]
 				break tryrun
 			}
+			if unalloc[it] < 1 && (atcapacity[it.ProviderType] || sch.pool.AtCapacity(it)) {
+				logger.Trace("not locking: AtCapacity and no unalloc workers")
+				atcapacity[it.ProviderType] = true
+				continue
+			}
 			if sch.pool.KillContainer(ctr.UUID, "about to lock") {
 				logger.Info("not locking: crunch-run process from previous attempt has not exited")
 				continue
@@ -115,9 +203,8 @@ tryrun:
 			unalloc[it]--
 		case arvados.ContainerStateLocked:
 			if sch.maxConcurrency > 0 && trying >= sch.maxConcurrency {
-				logger.Debugf("not starting: already at maxConcurrency %d", sch.maxConcurrency)
-				overquota = sorted[i:]
-				break tryrun
+				logger.Tracef("not starting: already at maxConcurrency %d", sch.maxConcurrency)
+				continue
 			}
 			trying++
 			if unalloc[it] > 0 {
@@ -130,6 +217,27 @@ tryrun:
 				logger.Trace("overquota")
 				overquota = sorted[i:]
 				break tryrun
+			} else if atcapacity[it.ProviderType] || sch.pool.AtCapacity(it) {
+				// Continue trying lower-priority
+				// containers in case they can run on
+				// different instance types that are
+				// available.
+				//
+				// The local "atcapacity" cache helps
+				// when the pool's flag resets after
+				// we look at container A but before
+				// we look at lower-priority container
+				// B. In that case we want to run
+				// container A on the next call to
+				// runQueue(), rather than run
+				// container B now.
+				//
+				// TODO: try running this container on
+				// a bigger (but not much more
+				// expensive) instance type.
+				logger.WithField("InstanceType", it.Name).Trace("at capacity")
+				atcapacity[it.ProviderType] = true
+				continue
 			} else if sch.pool.Create(it) {
 				// Success. (Note pool.Create works
 				// asynchronously and does its own
@@ -138,10 +246,7 @@ tryrun:
 				logger.Info("creating new instance")
 			} else {
 				// Failed despite not being at quota,
-				// e.g., cloud ops throttled.  TODO:
-				// avoid getting starved here if
-				// instances of a specific type always
-				// fail.
+				// e.g., cloud ops throttled.
 				logger.Trace("pool declined to create new instance")
 				continue
 			}
@@ -165,25 +270,48 @@ tryrun:
 	}
 
 	sch.mContainersAllocatedNotStarted.Set(float64(containerAllocatedWorkerBootingCount))
-	sch.mContainersNotAllocatedOverQuota.Set(float64(len(overquota)))
+	sch.mContainersNotAllocatedOverQuota.Set(float64(len(overquota) + len(overmaxsuper)))
 
-	if len(overquota) > 0 {
+	if len(overquota)+len(overmaxsuper) > 0 {
 		// Unlock any containers that are unmappable while
 		// we're at quota (but if they have already been
 		// scheduled and they're loading docker images etc.,
 		// let them run).
-		for _, ctr := range overquota {
+		var unlock []container.QueueEnt
+		unlock = append(unlock, overmaxsuper...)
+		if totalInstances > 0 && len(overquota) > 1 {
+			// We don't unlock the next-in-line container
+			// when at quota.  This avoids a situation
+			// where our "at quota" state expires, we lock
+			// the next container and try to create an
+			// instance, the cloud provider still returns
+			// a quota error, we unlock the container, and
+			// we repeat this until the container reaches
+			// its limit of lock/unlock cycles.
+			unlock = append(unlock, overquota[1:]...)
+		} else {
+			// However, if totalInstances is 0 and we're
+			// still getting quota errors, then the
+			// next-in-line container is evidently not
+			// possible to run, so we should let it
+			// exhaust its lock/unlock cycles and
+			// eventually cancel, to avoid starvation.
+			unlock = append(unlock, overquota...)
+		}
+		for _, ctr := range unlock {
 			ctr := ctr.Container
 			_, toolate := running[ctr.UUID]
 			if ctr.State == arvados.ContainerStateLocked && !toolate {
 				logger := sch.logger.WithField("ContainerUUID", ctr.UUID)
-				logger.Debug("unlock because pool capacity is used by higher priority containers")
+				logger.Info("unlock because pool capacity is used by higher priority containers")
 				err := sch.queue.Unlock(ctr.UUID)
 				if err != nil {
 					logger.WithError(err).Warn("error unlocking")
 				}
 			}
 		}
+	}
+	if len(overquota) > 0 {
 		// Shut down idle workers that didn't get any
 		// containers mapped onto them before we hit quota.
 		for it, n := range unalloc {