refactor(compute/service): Remove OpenTelemetry from "compute" modules

This change removes the OpenTelemetry integration from the OpenDC
Compute modules. Previously, we chose to integrate OpenTelemetry to
provide a unified way to report metrics to the users.

Although this worked as expected, the overhead of the OpenTelemetry when
collecting metrics during simulation was considerable and lacked more
optimization opportunities (other than providing a separate API
implementation). Furthermore, since we were tied to OpenTelemetry's SDK
implementation, we experienced issues with throttling and registering
multiple instruments.

We will instead use another approach, where we expose the core metrics
in OpenDC via specialized interfaces (see the commits before) such that
access is fast and can be done without having to interface with
OpenTelemetry. In addition, we will provide an adapter to that is able
to forward these metrics to OpenTelemetry implementations, so we can
still integrate with the wider ecosystem.

5 files changed, 10 insertions, 20 deletions

diff --git a/opendc-experiments/opendc-experiments-capelin/build.gradle.kts b/opendc-experiments/opendc-experiments-capelin/build.gradle.kts
index 9495f4ca..39cf101d 100644
--- a/opendc-experiments/opendc-experiments-capelin/build.gradle.kts
+++ b/opendc-experiments/opendc-experiments-capelin/build.gradle.kts
@@ -37,8 +37,6 @@ dependencies {
     implementation(projects.opendcSimulator.opendcSimulatorCore)
     implementation(projects.opendcSimulator.opendcSimulatorCompute)
     implementation(projects.opendcCompute.opendcComputeSimulator)
-    implementation(projects.opendcTelemetry.opendcTelemetrySdk)
-    implementation(projects.opendcTelemetry.opendcTelemetryCompute)
 
     implementation(libs.config)
     implementation(libs.kotlin.logging)
@@ -46,7 +44,6 @@ dependencies {
     implementation(libs.jackson.module.kotlin)
     implementation(libs.jackson.dataformat.csv)
     implementation(kotlin("reflect"))
-    implementation(libs.opentelemetry.semconv)
 
     runtimeOnly(projects.opendcTrace.opendcTraceOpendc)
 
diff --git a/opendc-experiments/opendc-experiments-capelin/src/jmh/kotlin/org/opendc/experiments/capelin/CapelinBenchmarks.kt b/opendc-experiments/opendc-experiments-capelin/src/jmh/kotlin/org/opendc/experiments/capelin/CapelinBenchmarks.kt
index 83b8c0c6..fd2c26f0 100644
--- a/opendc-experiments/opendc-experiments-capelin/src/jmh/kotlin/org/opendc/experiments/capelin/CapelinBenchmarks.kt
+++ b/opendc-experiments/opendc-experiments-capelin/src/jmh/kotlin/org/opendc/experiments/capelin/CapelinBenchmarks.kt
@@ -22,14 +22,12 @@
 
 package org.opendc.experiments.capelin
 
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import org.opendc.compute.service.scheduler.FilterScheduler
 import org.opendc.compute.service.scheduler.filters.ComputeFilter
 import org.opendc.compute.service.scheduler.filters.RamFilter
 import org.opendc.compute.service.scheduler.filters.VCpuFilter
 import org.opendc.compute.service.scheduler.weights.CoreRamWeigher
 import org.opendc.compute.workload.*
-import org.opendc.compute.workload.telemetry.NoopTelemetryManager
 import org.opendc.compute.workload.topology.Topology
 import org.opendc.compute.workload.topology.apply
 import org.opendc.experiments.capelin.topology.clusterTopology
@@ -46,7 +44,6 @@ import java.util.concurrent.TimeUnit
 @Fork(1)
 @Warmup(iterations = 2, time = 5, timeUnit = TimeUnit.SECONDS)
 @Measurement(iterations = 5, time = 5, timeUnit = TimeUnit.SECONDS)
-@OptIn(ExperimentalCoroutinesApi::class)
 class CapelinBenchmarks {
     private lateinit var vms: List<VirtualMachine>
     private lateinit var topology: Topology
@@ -59,7 +56,7 @@ class CapelinBenchmarks {
         val loader = ComputeWorkloadLoader(File("src/test/resources/trace"))
         val source = trace("bitbrains-small")
         vms = source.resolve(loader, Random(1L)).vms
-        topology = checkNotNull(object {}.javaClass.getResourceAsStream("/env/topology.txt")).use { clusterTopology(it) }
+        topology = checkNotNull(object {}.javaClass.getResourceAsStream("/topology.txt")).use { clusterTopology(it) }
     }
 
     @Benchmark
@@ -71,7 +68,6 @@ class CapelinBenchmarks {
         val runner = ComputeServiceHelper(
             coroutineContext,
             clock,
-            NoopTelemetryManager(),
             computeScheduler
         )
 
diff --git a/opendc-experiments/opendc-experiments-capelin/src/jmh/resources/topology.txt b/opendc-experiments/opendc-experiments-capelin/src/jmh/resources/topology.txt
new file mode 100644
index 00000000..6b347bff
--- /dev/null
+++ b/opendc-experiments/opendc-experiments-capelin/src/jmh/resources/topology.txt
@@ -0,0 +1,5 @@
+ClusterID;ClusterName;Cores;Speed;Memory;numberOfHosts;memoryCapacityPerHost;coreCountPerHost
+A01;A01;32;3.2;2048;1;256;32
+B01;B01;48;2.93;1256;6;64;8
+C01;C01;32;3.2;2048;2;128;16
+
diff --git a/opendc-experiments/opendc-experiments-capelin/src/main/kotlin/org/opendc/experiments/capelin/Portfolio.kt b/opendc-experiments/opendc-experiments-capelin/src/main/kotlin/org/opendc/experiments/capelin/Portfolio.kt
index 6fd85e8c..0de8aa7b 100644
--- a/opendc-experiments/opendc-experiments-capelin/src/main/kotlin/org/opendc/experiments/capelin/Portfolio.kt
+++ b/opendc-experiments/opendc-experiments-capelin/src/main/kotlin/org/opendc/experiments/capelin/Portfolio.kt
@@ -30,7 +30,7 @@ import org.opendc.compute.workload.ComputeWorkloadLoader
 import org.opendc.compute.workload.createComputeScheduler
 import org.opendc.compute.workload.export.parquet.ParquetComputeMonitor
 import org.opendc.compute.workload.grid5000
-import org.opendc.compute.workload.telemetry.NoopTelemetryManager
+import org.opendc.compute.workload.telemetry.ComputeMetricReader
 import org.opendc.compute.workload.topology.apply
 import org.opendc.experiments.capelin.model.OperationalPhenomena
 import org.opendc.experiments.capelin.model.Topology
@@ -39,7 +39,6 @@ import org.opendc.experiments.capelin.topology.clusterTopology
 import org.opendc.harness.dsl.Experiment
 import org.opendc.harness.dsl.anyOf
 import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.telemetry.compute.ComputeMetricReader
 import java.io.File
 import java.time.Duration
 import java.util.*
@@ -99,11 +98,9 @@ abstract class Portfolio(name: String) : Experiment(name) {
             else
                 null
         val (vms, interferenceModel) = workload.source.resolve(workloadLoader, seeder)
-        val telemetry = NoopTelemetryManager()
         val runner = ComputeServiceHelper(
             coroutineContext,
             clock,
-            telemetry,
             computeScheduler,
             failureModel,
             interferenceModel?.withSeed(repeat.toLong())
diff --git a/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt b/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
index 62cdf123..fa2cd9c8 100644
--- a/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
+++ b/opendc-experiments/opendc-experiments-capelin/src/test/kotlin/org/opendc/experiments/capelin/CapelinIntegrationTest.kt
@@ -33,14 +33,13 @@ import org.opendc.compute.service.scheduler.filters.RamFilter
 import org.opendc.compute.service.scheduler.filters.VCpuFilter
 import org.opendc.compute.service.scheduler.weights.CoreRamWeigher
 import org.opendc.compute.workload.*
-import org.opendc.compute.workload.telemetry.NoopTelemetryManager
+import org.opendc.compute.workload.telemetry.ComputeMetricReader
+import org.opendc.compute.workload.telemetry.ComputeMonitor
+import org.opendc.compute.workload.telemetry.table.HostTableReader
 import org.opendc.compute.workload.topology.Topology
 import org.opendc.compute.workload.topology.apply
 import org.opendc.experiments.capelin.topology.clusterTopology
 import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.telemetry.compute.ComputeMetricReader
-import org.opendc.telemetry.compute.ComputeMonitor
-import org.opendc.telemetry.compute.table.HostTableReader
 import java.io.File
 import java.time.Duration
 import java.util.*
@@ -86,7 +85,6 @@ class CapelinIntegrationTest {
         val runner = ComputeServiceHelper(
             coroutineContext,
             clock,
-            NoopTelemetryManager(),
             computeScheduler
         )
         val topology = createTopology()
@@ -136,7 +134,6 @@ class CapelinIntegrationTest {
         val runner = ComputeServiceHelper(
             coroutineContext,
             clock,
-            NoopTelemetryManager(),
             computeScheduler
         )
         val topology = createTopology("single")
@@ -182,7 +179,6 @@ class CapelinIntegrationTest {
         val simulator = ComputeServiceHelper(
             coroutineContext,
             clock,
-            NoopTelemetryManager(),
             computeScheduler,
             interferenceModel = interferenceModel?.withSeed(seed.toLong())
         )
@@ -226,7 +222,6 @@ class CapelinIntegrationTest {
         val simulator = ComputeServiceHelper(
             coroutineContext,
             clock,
-            NoopTelemetryManager(),
             computeScheduler,
             grid5000(Duration.ofDays(7))
         )