compute: Integrate OpenTelemetry Metrics in OpenDC Workflow

This change integrates the OpenTelemetry Metrics API in the OpenDC
Workflow Service implementation. This replaces the old infrastructure for
gathering metrics.

11 files changed, 261 insertions, 432 deletions

diff --git a/simulator/opendc-experiments/opendc-experiments-sc18/.gitignore b/simulator/opendc-experiments/opendc-experiments-sc18/.gitignore
deleted file mode 100644
index ba64707c..00000000
--- a/simulator/opendc-experiments/opendc-experiments-sc18/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-input/
-output/
diff --git a/simulator/opendc-experiments/opendc-experiments-sc18/build.gradle.kts b/simulator/opendc-experiments/opendc-experiments-sc18/build.gradle.kts
deleted file mode 100644
index 02e77c7c..00000000
--- a/simulator/opendc-experiments/opendc-experiments-sc18/build.gradle.kts
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (c) 2019 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-description = "Experiments for the SC18 article"
-
-/* Build configuration */
-plugins {
-    `kotlin-library-conventions`
-    `experiment-conventions`
-}
-
-dependencies {
-    api(platform(project(":opendc-platform")))
-    api(project(":opendc-harness"))
-    implementation(project(":opendc-format"))
-    implementation(project(":opendc-workflow:opendc-workflow-service"))
-    implementation(project(":opendc-simulator:opendc-simulator-core"))
-    implementation(project(":opendc-compute:opendc-compute-simulator"))
-}
diff --git a/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/UnderspecificationExperiment.kt b/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/UnderspecificationExperiment.kt
deleted file mode 100644
index 225200c9..00000000
--- a/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/UnderspecificationExperiment.kt
+++ /dev/null
@@ -1,138 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.experiments.sc18
-
-import io.opentelemetry.api.metrics.MeterProvider
-import kotlinx.coroutines.*
-import kotlinx.coroutines.test.TestCoroutineScope
-import org.opendc.compute.service.ComputeService
-import org.opendc.compute.service.scheduler.NumberOfActiveServersAllocationPolicy
-import org.opendc.compute.simulator.SimHost
-import org.opendc.format.environment.sc18.Sc18EnvironmentReader
-import org.opendc.format.trace.gwf.GwfTraceReader
-import org.opendc.harness.dsl.Experiment
-import org.opendc.harness.dsl.anyOf
-import org.opendc.simulator.compute.SimSpaceSharedHypervisorProvider
-import org.opendc.simulator.utils.DelayControllerClockAdapter
-import org.opendc.trace.core.EventTracer
-import org.opendc.trace.core.enable
-import org.opendc.workflow.service.WorkflowEvent
-import org.opendc.workflow.service.WorkflowService
-import org.opendc.workflow.service.scheduler.WorkflowSchedulerMode
-import org.opendc.workflow.service.scheduler.job.NullJobAdmissionPolicy
-import org.opendc.workflow.service.scheduler.job.SubmissionTimeJobOrderPolicy
-import org.opendc.workflow.service.scheduler.task.NullTaskEligibilityPolicy
-import org.opendc.workflow.service.scheduler.task.SubmissionTimeTaskOrderPolicy
-import java.io.File
-import java.io.FileInputStream
-import kotlin.math.max
-
-/**
- * The [UnderspecificationExperiment] investigates the impact of scheduler underspecification on  performance.
- * It focuses on components that must exist (that is, based on their own publications, the correct operation of the
- * schedulers under study requires these components), yet have been left underspecified by their author.
- */
-public class UnderspecificationExperiment : Experiment("underspecification") {
-    /**
-     * The workflow traces to test.
-     */
-    private val trace: String by anyOf("input/traces/chronos_exp_noscaler_ca.gwf")
-
-    /**
-     * The datacenter environments to test.
-     */
-    private val environment: String by anyOf("input/environments/base.json")
-
-    @OptIn(ExperimentalCoroutinesApi::class)
-    override fun doRun(repeat: Int) {
-        val testScope = TestCoroutineScope()
-        val clock = DelayControllerClockAdapter(testScope)
-        val tracer = EventTracer(clock)
-        val recording = tracer.openRecording().run {
-            enable<WorkflowEvent.JobSubmitted>()
-            enable<WorkflowEvent.JobStarted>()
-            enable<WorkflowEvent.JobFinished>()
-            enable<WorkflowEvent.TaskStarted>()
-            enable<WorkflowEvent.TaskFinished>()
-            this
-        }
-
-        testScope.launch {
-            launch { println("MAKESPAN: ${recording.workflowRuntime()}") }
-            launch { println("WAIT: ${recording.workflowWaitingTime()}") }
-            recording.start()
-        }
-
-        testScope.launch {
-            val hosts = Sc18EnvironmentReader(FileInputStream(File(environment)))
-                .use { it.read() }
-                .map { def ->
-                    SimHost(
-                        def.uid,
-                        def.name,
-                        def.model,
-                        def.meta,
-                        testScope.coroutineContext,
-                        clock,
-                        SimSpaceSharedHypervisorProvider()
-                    )
-                }
-
-            val compute = ComputeService(
-                testScope.coroutineContext,
-                clock,
-                MeterProvider.noop().get("opendc-compute"),
-                NumberOfActiveServersAllocationPolicy(),
-            )
-
-            hosts.forEach { compute.addHost(it) }
-
-            val scheduler = WorkflowService(
-                testScope.coroutineContext,
-                clock,
-                tracer,
-                compute.newClient(),
-                mode = WorkflowSchedulerMode.Batch(100),
-                jobAdmissionPolicy = NullJobAdmissionPolicy,
-                jobOrderPolicy = SubmissionTimeJobOrderPolicy(),
-                taskEligibilityPolicy = NullTaskEligibilityPolicy,
-                taskOrderPolicy = SubmissionTimeTaskOrderPolicy(),
-            )
-
-            val reader = GwfTraceReader(File(trace))
-
-            while (reader.hasNext()) {
-                val entry = reader.next()
-                delay(max(0, entry.start * 1000 - clock.millis()))
-                scheduler.submit(entry.workload)
-            }
-        }
-
-        testScope.advanceUntilIdle()
-        recording.close()
-
-        // Check whether everything went okay
-        testScope.uncaughtExceptions.forEach { it.printStackTrace() }
-        assert(testScope.uncaughtExceptions.isEmpty()) { "Errors occurred during execution of the experiment" }
-    }
-}
diff --git a/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/WorkflowMetrics.kt b/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/WorkflowMetrics.kt
deleted file mode 100644
index a8356888..00000000
--- a/simulator/opendc-experiments/opendc-experiments-sc18/src/main/kotlin/org/opendc/experiments/sc18/WorkflowMetrics.kt
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.experiments.sc18
-
-import org.opendc.trace.core.EventStream
-import org.opendc.trace.core.onEvent
-import org.opendc.workflow.service.WorkflowEvent
-import java.util.*
-import kotlin.coroutines.resume
-import kotlin.coroutines.suspendCoroutine
-
-/**
- * This function collects the makespan of workflows that appear in the event stream.
- */
-public suspend fun EventStream.workflowRuntime(): Map<UUID, Long> = suspendCoroutine { cont ->
-    val starts = mutableMapOf<UUID, Long>()
-    val results = mutableMapOf<UUID, Long>()
-
-    onEvent<WorkflowEvent.JobStarted> {
-        starts[it.job.uid] = it.timestamp
-    }
-    onEvent<WorkflowEvent.JobFinished> {
-        val start = starts.remove(it.job.uid) ?: return@onEvent
-        results[it.job.uid] = it.timestamp - start
-    }
-    onClose { cont.resume(results) }
-}
-
-/**
- * This function collects the waiting time of workflows that appear in the event stream, which the duration between the
- * workflow submission and the start of the first task.
- */
-public suspend fun EventStream.workflowWaitingTime(): Map<UUID, Long> = suspendCoroutine { cont ->
-    val starts = mutableMapOf<UUID, Long>()
-    val results = mutableMapOf<UUID, Long>()
-
-    onEvent<WorkflowEvent.JobStarted> {
-        starts[it.job.uid] = it.timestamp
-    }
-    onEvent<WorkflowEvent.TaskStarted> {
-        results.computeIfAbsent(it.job.uid) { _ ->
-            val start = starts.remove(it.job.uid)!!
-            it.timestamp - start
-        }
-    }
-    onClose { cont.resume(results) }
-}
-
-/**
- * This function collects the response time of tasks that appear in the event stream.
- */
-public suspend fun EventStream.taskResponse(): Map<UUID, Long> = suspendCoroutine { cont ->
-    val starts = mutableMapOf<UUID, Long>()
-    val results = mutableMapOf<UUID, Long>()
-
-    onEvent<WorkflowEvent.JobSubmitted> {
-        for (task in it.job.tasks) {
-            starts[task.uid] = it.timestamp
-        }
-    }
-    onEvent<WorkflowEvent.TaskFinished> {
-        val start = starts.remove(it.job.uid) ?: return@onEvent
-        results[it.task.uid] = it.timestamp - start
-    }
-    onClose { cont.resume(results) }
-}
diff --git a/simulator/opendc-workflow/opendc-workflow-service/build.gradle.kts b/simulator/opendc-workflow/opendc-workflow-service/build.gradle.kts
index bec18ae9..5625c3d8 100644
--- a/simulator/opendc-workflow/opendc-workflow-service/build.gradle.kts
+++ b/simulator/opendc-workflow/opendc-workflow-service/build.gradle.kts
@@ -34,12 +34,14 @@ dependencies {
     api(project(":opendc-workflow:opendc-workflow-api"))
     api(project(":opendc-compute:opendc-compute-api"))
     api(project(":opendc-trace:opendc-trace-core"))
+    api(project(":opendc-telemetry:opendc-telemetry-api"))
     implementation(project(":opendc-utils"))
     implementation("io.github.microutils:kotlin-logging")
 
     testImplementation(project(":opendc-simulator:opendc-simulator-core"))
     testImplementation(project(":opendc-compute:opendc-compute-simulator"))
     testImplementation(project(":opendc-format"))
+    testImplementation(project(":opendc-telemetry:opendc-telemetry-sdk"))
     testImplementation("com.fasterxml.jackson.module:jackson-module-kotlin:${versions["jackson-module-kotlin"]}")
     testRuntimeOnly("org.apache.logging.log4j:log4j-slf4j-impl")
 }
diff --git a/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/WorkflowService.kt b/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/WorkflowService.kt
index 2f83e376..94302790 100644
--- a/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/WorkflowService.kt
+++ b/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/WorkflowService.kt
@@ -22,6 +22,7 @@
 
 package org.opendc.workflow.service
 
+import io.opentelemetry.api.metrics.Meter
 import kotlinx.coroutines.flow.Flow
 import org.opendc.compute.api.ComputeClient
 import org.opendc.trace.core.EventTracer
@@ -42,14 +43,14 @@ import kotlin.coroutines.CoroutineContext
  */
 public interface WorkflowService : AutoCloseable {
     /**
-     * The events emitted by the workflow scheduler.
+     * Submit the specified [Job] to the workflow service for scheduling.
      */
-    public val events: Flow<WorkflowEvent>
+    public suspend fun submit(job: Job)
 
     /**
-     * Submit the specified [Job] to the workflow service for scheduling.
+     * Run the specified [Job] and suspend execution until the job is finished.
      */
-    public suspend fun submit(job: Job)
+    public suspend fun run(job: Job)
 
     /**
      * Terminate the lifecycle of the workflow service, stopping all running workflows.
@@ -63,6 +64,7 @@ public interface WorkflowService : AutoCloseable {
          * @param context The [CoroutineContext] to use in the service.
          * @param clock The clock instance to use.
          * @param tracer The event tracer to use.
+         * @param meter The meter to use.
          * @param compute The compute client to use.
          * @param mode The scheduling mode to use.
          * @param jobAdmissionPolicy The job admission policy to use.
@@ -74,6 +76,7 @@ public interface WorkflowService : AutoCloseable {
             context: CoroutineContext,
             clock: Clock,
             tracer: EventTracer,
+            meter: Meter,
             compute: ComputeClient,
             mode: WorkflowSchedulerMode,
             jobAdmissionPolicy: JobAdmissionPolicy,
@@ -85,6 +88,7 @@ public interface WorkflowService : AutoCloseable {
                 context,
                 clock,
                 tracer,
+                meter,
                 compute,
                 mode,
                 jobAdmissionPolicy,
diff --git a/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/internal/WorkflowServiceImpl.kt b/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/internal/WorkflowServiceImpl.kt
index 85a88acd..1aef6f8e 100644
--- a/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/internal/WorkflowServiceImpl.kt
+++ b/simulator/opendc-workflow/opendc-workflow-service/src/main/kotlin/org/opendc/workflow/service/internal/WorkflowServiceImpl.kt
@@ -22,12 +22,10 @@
 
 package org.opendc.workflow.service.internal
 
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.cancel
+import io.opentelemetry.api.metrics.Meter
+import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.launch
 import mu.KotlinLogging
 import org.opendc.compute.api.*
 import org.opendc.trace.core.EventTracer
@@ -43,7 +41,9 @@ import org.opendc.workflow.service.scheduler.task.TaskEligibilityPolicy
 import org.opendc.workflow.service.scheduler.task.TaskOrderPolicy
 import java.time.Clock
 import java.util.*
+import kotlin.coroutines.Continuation
 import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.resume
 
 /**
  * A [WorkflowService] that distributes work through a multi-stage process based on the Reference Architecture for
@@ -53,6 +53,7 @@ public class WorkflowServiceImpl(
     context: CoroutineContext,
     internal val clock: Clock,
     internal val tracer: EventTracer,
+    private val meter: Meter,
     private val computeClient: ComputeClient,
     mode: WorkflowSchedulerMode,
     jobAdmissionPolicy: JobAdmissionPolicy,
@@ -63,7 +64,7 @@ public class WorkflowServiceImpl(
     /**
      * The [CoroutineScope] of the service bounded by the lifecycle of the service.
      */
-    internal val scope = CoroutineScope(context)
+    internal val scope = CoroutineScope(context + Job())
 
     /**
      * The logger instance to use.
@@ -106,6 +107,11 @@ public class WorkflowServiceImpl(
     internal val taskByServer = mutableMapOf<Server, TaskState>()
 
     /**
+     * The continuation of the jobs.
+     */
+    private val conts = mutableMapOf<Job, Continuation<Unit>>()
+
+    /**
      * The root listener of this scheduler.
      */
     private val rootListener = object : WorkflowSchedulerListener {
@@ -151,6 +157,54 @@ public class WorkflowServiceImpl(
         }
     }
 
+    /**
+     * The number of jobs that have been submitted to the service.
+     */
+    private val submittedJobs = meter.longCounterBuilder("jobs.submitted")
+        .setDescription("Number of submitted jobs")
+        .setUnit("1")
+        .build()
+
+    /**
+     * The number of jobs that are running.
+     */
+    private val runningJobs = meter.longUpDownCounterBuilder("jobs.active")
+        .setDescription("Number of jobs running")
+        .setUnit("1")
+        .build()
+
+    /**
+     * The number of jobs that have finished running.
+     */
+    private val finishedJobs = meter.longCounterBuilder("jobs.finished")
+        .setDescription("Number of jobs that finished running")
+        .setUnit("1")
+        .build()
+
+    /**
+     * The number of tasks that have been submitted to the service.
+     */
+    private val submittedTasks = meter.longCounterBuilder("tasks.submitted")
+        .setDescription("Number of submitted tasks")
+        .setUnit("1")
+        .build()
+
+    /**
+     * The number of jobs that are running.
+     */
+    private val runningTasks = meter.longUpDownCounterBuilder("tasks.active")
+        .setDescription("Number of tasks running")
+        .setUnit("1")
+        .build()
+
+    /**
+     * The number of jobs that have finished running.
+     */
+    private val finishedTasks = meter.longCounterBuilder("tasks.finished")
+        .setDescription("Number of tasks that finished running")
+        .setUnit("1")
+        .build()
+
     private val mode: WorkflowSchedulerMode.Logic
     private val jobAdmissionPolicy: JobAdmissionPolicy.Logic
     private val taskEligibilityPolicy: TaskEligibilityPolicy.Logic
@@ -167,16 +221,7 @@ public class WorkflowServiceImpl(
         }
     }
 
-    override val events: Flow<WorkflowEvent> = tracer.openRecording().let {
-        it.enable<WorkflowEvent.JobSubmitted>()
-        it.enable<WorkflowEvent.JobStarted>()
-        it.enable<WorkflowEvent.JobFinished>()
-        it.enable<WorkflowEvent.TaskStarted>()
-        it.enable<WorkflowEvent.TaskFinished>()
-        it.consumeAsFlow().map { event -> event as WorkflowEvent }
-    }
-
-    override suspend fun submit(job: Job) {
+    override suspend fun run(job: Job) {
         // J1 Incoming Jobs
         val jobInstance = JobState(job, clock.millis())
         val instances = job.tasks.associateWith {
@@ -193,14 +238,25 @@ public class WorkflowServiceImpl(
             if (instance.isRoot) {
                 instance.state = TaskStatus.READY
             }
+
+            submittedTasks.add(1)
         }
 
-        instances.values.toCollection(jobInstance.tasks)
-        incomingJobs += jobInstance
-        rootListener.jobSubmitted(jobInstance)
-        tracer.commit(WorkflowEvent.JobSubmitted(this, jobInstance.job))
+        return suspendCancellableCoroutine { cont ->
+            instances.values.toCollection(jobInstance.tasks)
+            incomingJobs += jobInstance
+            rootListener.jobSubmitted(jobInstance)
+            conts[job] = cont
+
+            submittedJobs.add(1)
+            tracer.commit(WorkflowEvent.JobSubmitted(this, jobInstance.job))
 
-        requestCycle()
+            requestCycle()
+        }
+    }
+
+    override suspend fun submit(job: Job) {
+        scope.launch { run(job) }
     }
 
     override fun close() {
@@ -231,6 +287,8 @@ public class WorkflowServiceImpl(
             iterator.remove()
             jobQueue.add(jobInstance)
             activeJobs += jobInstance
+
+            runningJobs.add(1)
             tracer.commit(
                 WorkflowEvent.JobStarted(
                     this,
@@ -311,11 +369,11 @@ public class WorkflowServiceImpl(
 
     public override fun onStateChanged(server: Server, newState: ServerState) {
         when (newState) {
-            ServerState.PROVISIONING -> {
-            }
+            ServerState.PROVISIONING -> {}
             ServerState.RUNNING -> {
                 val task = taskByServer.getValue(server)
                 task.startedAt = clock.millis()
+                runningTasks.add(1)
                 tracer.commit(
                     WorkflowEvent.TaskStarted(
                         this@WorkflowServiceImpl,
@@ -338,6 +396,9 @@ public class WorkflowServiceImpl(
                 task.finishedAt = clock.millis()
                 job.tasks.remove(task)
                 activeTasks -= task
+
+                runningTasks.add(-1)
+                finishedTasks.add(1)
                 tracer.commit(
                     WorkflowEvent.TaskFinished(
                         this@WorkflowServiceImpl,
@@ -371,8 +432,12 @@ public class WorkflowServiceImpl(
 
     private fun finishJob(job: JobState) {
         activeJobs -= job
+        runningJobs.add(-1)
+        finishedJobs.add(1)
         tracer.commit(WorkflowEvent.JobFinished(this, job.job))
         rootListener.jobFinished(job)
+
+        conts.remove(job.job)?.resume(Unit)
     }
 
     public fun addListener(listener: WorkflowSchedulerListener) {
diff --git a/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/StageWorkflowSchedulerIntegrationTest.kt b/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/StageWorkflowSchedulerIntegrationTest.kt
deleted file mode 100644
index 5e276edf..00000000
--- a/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/StageWorkflowSchedulerIntegrationTest.kt
+++ /dev/null
@@ -1,141 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.workflow.service
-
-import io.opentelemetry.api.metrics.MeterProvider
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.flow.onEach
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.test.TestCoroutineScope
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Assertions.assertNotEquals
-import org.junit.jupiter.api.DisplayName
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertAll
-import org.opendc.compute.service.ComputeService
-import org.opendc.compute.service.scheduler.NumberOfActiveServersAllocationPolicy
-import org.opendc.compute.simulator.SimHost
-import org.opendc.format.environment.sc18.Sc18EnvironmentReader
-import org.opendc.format.trace.gwf.GwfTraceReader
-import org.opendc.simulator.compute.SimSpaceSharedHypervisorProvider
-import org.opendc.simulator.utils.DelayControllerClockAdapter
-import org.opendc.trace.core.EventTracer
-import org.opendc.workflow.service.internal.WorkflowServiceImpl
-import org.opendc.workflow.service.scheduler.WorkflowSchedulerMode
-import org.opendc.workflow.service.scheduler.job.NullJobAdmissionPolicy
-import org.opendc.workflow.service.scheduler.job.SubmissionTimeJobOrderPolicy
-import org.opendc.workflow.service.scheduler.task.NullTaskEligibilityPolicy
-import org.opendc.workflow.service.scheduler.task.SubmissionTimeTaskOrderPolicy
-import kotlin.math.max
-
-/**
- * Integration test suite for the [WorkflowServiceImpl].
- */
-@DisplayName("WorkflowServiceImpl")
-@OptIn(ExperimentalCoroutinesApi::class)
-internal class StageWorkflowSchedulerIntegrationTest {
-    /**
-     * A large integration test where we check whether all tasks in some trace are executed correctly.
-     */
-    @Test
-    fun testTrace() {
-        var jobsSubmitted = 0L
-        var jobsStarted = 0L
-        var jobsFinished = 0L
-        var tasksStarted = 0L
-        var tasksFinished = 0L
-
-        val testScope = TestCoroutineScope()
-        val clock = DelayControllerClockAdapter(testScope)
-        val tracer = EventTracer(clock)
-
-        val scheduler = let {
-            val hosts = Sc18EnvironmentReader(object {}.javaClass.getResourceAsStream("/environment.json"))
-                .use { it.read() }
-                .map { def ->
-                    SimHost(
-                        def.uid,
-                        def.name,
-                        def.model,
-                        def.meta,
-                        testScope.coroutineContext,
-                        clock,
-                        SimSpaceSharedHypervisorProvider()
-                    )
-                }
-
-            val meter = MeterProvider.noop().get("opendc-compute")
-            val compute = ComputeService(testScope.coroutineContext, clock, meter, NumberOfActiveServersAllocationPolicy(), schedulingQuantum = 1000)
-
-            hosts.forEach { compute.addHost(it) }
-
-            WorkflowService(
-                testScope.coroutineContext,
-                clock,
-                tracer,
-                compute.newClient(),
-                mode = WorkflowSchedulerMode.Batch(100),
-                jobAdmissionPolicy = NullJobAdmissionPolicy,
-                jobOrderPolicy = SubmissionTimeJobOrderPolicy(),
-                taskEligibilityPolicy = NullTaskEligibilityPolicy,
-                taskOrderPolicy = SubmissionTimeTaskOrderPolicy(),
-            )
-        }
-
-        testScope.launch {
-            scheduler.events
-                .onEach { event ->
-                    when (event) {
-                        is WorkflowEvent.JobStarted -> jobsStarted++
-                        is WorkflowEvent.JobFinished -> jobsFinished++
-                        is WorkflowEvent.TaskStarted -> tasksStarted++
-                        is WorkflowEvent.TaskFinished -> tasksFinished++
-                    }
-                }
-                .collect()
-        }
-
-        testScope.launch {
-            val reader = GwfTraceReader(object {}.javaClass.getResourceAsStream("/trace.gwf"))
-
-            while (reader.hasNext()) {
-                val entry = reader.next()
-                jobsSubmitted++
-                delay(max(0, entry.start - clock.millis()))
-                scheduler.submit(entry.workload)
-            }
-        }
-
-        testScope.advanceUntilIdle()
-
-        assertAll(
-            { assertEquals(emptyList<Throwable>(), testScope.uncaughtExceptions) },
-            { assertNotEquals(0, jobsSubmitted, "No jobs submitted") },
-            { assertEquals(jobsSubmitted, jobsStarted, "Not all submitted jobs started") },
-            { assertEquals(jobsSubmitted, jobsFinished, "Not all started jobs finished") },
-            { assertEquals(tasksStarted, tasksFinished, "Not all started tasks finished") }
-        )
-    }
-}
diff --git a/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceIntegrationTest.kt b/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceIntegrationTest.kt
new file mode 100644
index 00000000..28fe76c7
--- /dev/null
+++ b/simulator/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceIntegrationTest.kt
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.workflow.service
+
+import io.opentelemetry.api.metrics.MeterProvider
+import io.opentelemetry.sdk.metrics.SdkMeterProvider
+import io.opentelemetry.sdk.metrics.export.MetricProducer
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.runBlockingTest
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertAll
+import org.opendc.compute.service.ComputeService
+import org.opendc.compute.service.scheduler.NumberOfActiveServersAllocationPolicy
+import org.opendc.compute.simulator.SimHost
+import org.opendc.format.environment.sc18.Sc18EnvironmentReader
+import org.opendc.format.trace.gwf.GwfTraceReader
+import org.opendc.simulator.compute.SimSpaceSharedHypervisorProvider
+import org.opendc.simulator.utils.DelayControllerClockAdapter
+import org.opendc.telemetry.sdk.toOtelClock
+import org.opendc.trace.core.EventTracer
+import org.opendc.workflow.service.internal.WorkflowServiceImpl
+import org.opendc.workflow.service.scheduler.WorkflowSchedulerMode
+import org.opendc.workflow.service.scheduler.job.NullJobAdmissionPolicy
+import org.opendc.workflow.service.scheduler.job.SubmissionTimeJobOrderPolicy
+import org.opendc.workflow.service.scheduler.task.NullTaskEligibilityPolicy
+import org.opendc.workflow.service.scheduler.task.SubmissionTimeTaskOrderPolicy
+import kotlin.math.max
+
+/**
+ * Integration test suite for the [WorkflowServiceImpl].
+ */
+@DisplayName("WorkflowServiceImpl")
+@OptIn(ExperimentalCoroutinesApi::class)
+internal class WorkflowServiceIntegrationTest {
+    /**
+     * A large integration test where we check whether all tasks in some trace are executed correctly.
+     */
+    @Test
+    fun testTrace() = runBlockingTest {
+        val clock = DelayControllerClockAdapter(this)
+        val tracer = EventTracer(clock)
+
+        val meterProvider: MeterProvider = SdkMeterProvider
+            .builder()
+            .setClock(clock.toOtelClock())
+            .build()
+
+        val hosts = Sc18EnvironmentReader(object {}.javaClass.getResourceAsStream("/environment.json"))
+            .use { it.read() }
+            .map { def ->
+                SimHost(
+                    def.uid,
+                    def.name,
+                    def.model,
+                    def.meta,
+                    coroutineContext,
+                    clock,
+                    SimSpaceSharedHypervisorProvider()
+                )
+            }
+
+        val meter = MeterProvider.noop().get("opendc-compute")
+        val compute = ComputeService(coroutineContext, clock, meter, NumberOfActiveServersAllocationPolicy(), schedulingQuantum = 1000)
+
+        hosts.forEach { compute.addHost(it) }
+
+        val scheduler = WorkflowService(
+            coroutineContext,
+            clock,
+            tracer,
+            meterProvider.get("opendc-workflow"),
+            compute.newClient(),
+            mode = WorkflowSchedulerMode.Batch(100),
+            jobAdmissionPolicy = NullJobAdmissionPolicy,
+            jobOrderPolicy = SubmissionTimeJobOrderPolicy(),
+            taskEligibilityPolicy = NullTaskEligibilityPolicy,
+            taskOrderPolicy = SubmissionTimeTaskOrderPolicy(),
+        )
+
+        val reader = GwfTraceReader(object {}.javaClass.getResourceAsStream("/trace.gwf"))
+        var offset = Long.MIN_VALUE
+
+        coroutineScope {
+            while (reader.hasNext()) {
+                val entry = reader.next()
+
+                if (offset < 0) {
+                    offset = entry.start - clock.millis()
+                }
+
+                delay(max(0, (entry.start - offset) - clock.millis()))
+                launch {
+                    scheduler.run(entry.workload)
+                }
+            }
+        }
+
+        hosts.forEach(SimHost::close)
+        scheduler.close()
+        compute.close()
+
+        val metrics = collectMetrics(meterProvider as MetricProducer)
+
+        assertAll(
+            { assertEquals(758, metrics.jobsSubmitted, "No jobs submitted") },
+            { assertEquals(0, metrics.jobsActive, "Not all submitted jobs started") },
+            { assertEquals(metrics.jobsSubmitted, metrics.jobsFinished, "Not all started jobs finished") },
+            { assertEquals(0, metrics.tasksActive, "Not all started tasks finished") },
+            { assertEquals(metrics.tasksSubmitted, metrics.tasksFinished, "Not all started tasks finished") }
+        )
+    }
+
+    class WorkflowMetrics {
+        var jobsSubmitted = 0L
+        var jobsActive = 0L
+        var jobsFinished = 0L
+        var tasksSubmitted = 0L
+        var tasksActive = 0L
+        var tasksFinished = 0L
+    }
+
+    /**
+     * Collect the metrics of the workflow service.
+     */
+    private fun collectMetrics(metricProducer: MetricProducer): WorkflowMetrics {
+        val metrics = metricProducer.collectAllMetrics().associateBy { it.name }
+        val res = WorkflowMetrics()
+        res.jobsSubmitted = metrics["jobs.submitted"]?.longSumData?.points?.last()?.value ?: 0
+        res.jobsActive = metrics["jobs.active"]?.longSumData?.points?.last()?.value ?: 0
+        res.jobsFinished = metrics["jobs.finished"]?.longSumData?.points?.last()?.value ?: 0
+        res.tasksSubmitted = metrics["tasks.submitted"]?.longSumData?.points?.last()?.value ?: 0
+        res.tasksActive = metrics["tasks.active"]?.longSumData?.points?.last()?.value ?: 0
+        res.tasksFinished = metrics["tasks.finished"]?.longSumData?.points?.last()?.value ?: 0
+        return res
+    }
+}
diff --git a/simulator/opendc-workflow/opendc-workflow-service/src/test/resources/log4j2.xml b/simulator/opendc-workflow/opendc-workflow-service/src/test/resources/log4j2.xml
index 70a0eacc..edcf41ed 100644
--- a/simulator/opendc-workflow/opendc-workflow-service/src/test/resources/log4j2.xml
+++ b/simulator/opendc-workflow/opendc-workflow-service/src/test/resources/log4j2.xml
@@ -28,6 +28,9 @@
         </Console>
     </Appenders>
     <Loggers>
+        <Logger name="org.opendc.workflow" level="info" additivity="false">
+            <AppenderRef ref="Console"/>
+        </Logger>
         <Root level="warn">
             <AppenderRef ref="Console"/>
         </Root>
diff --git a/simulator/settings.gradle.kts b/simulator/settings.gradle.kts
index 73b4d8e7..a7a55b1c 100644
--- a/simulator/settings.gradle.kts
+++ b/simulator/settings.gradle.kts
@@ -31,7 +31,6 @@ include(":opendc-serverless:opendc-serverless-api")
 include(":opendc-serverless:opendc-serverless-service")
 include(":opendc-serverless:opendc-serverless-simulator")
 include(":opendc-format")
-include(":opendc-experiments:opendc-experiments-sc18")
 include(":opendc-experiments:opendc-experiments-capelin")
 include(":opendc-runner-web")
 include(":opendc-simulator:opendc-simulator-core")