refactor(telemetry): Create separate MeterProvider per service/host

This change refactors the telemetry implementation by creating a
separate MeterProvider per service or host. This means we have to keep
track of multiple metric producers, but that we can attach resource
information to each of the MeterProviders like we would in a real world
scenario.

7 files changed, 139 insertions, 96 deletions

diff --git a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/ComputeService.kt b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/ComputeService.kt
index 1873eb99..2a1fbaa0 100644
--- a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/ComputeService.kt
+++ b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/ComputeService.kt
@@ -23,11 +23,13 @@
 package org.opendc.compute.service
 
 import io.opentelemetry.api.metrics.Meter
+import io.opentelemetry.api.metrics.MeterProvider
 import org.opendc.compute.api.ComputeClient
 import org.opendc.compute.service.driver.Host
 import org.opendc.compute.service.internal.ComputeServiceImpl
 import org.opendc.compute.service.scheduler.ComputeScheduler
 import java.time.Clock
+import java.time.Duration
 import kotlin.coroutines.CoroutineContext
 
 /**
@@ -70,16 +72,18 @@ public interface ComputeService : AutoCloseable {
          *
          * @param context The [CoroutineContext] to use in the service.
          * @param clock The clock instance to use.
+         * @param meterProvider The [MeterProvider] for creating a [Meter] for the service.
          * @param scheduler The scheduler implementation to use.
+         * @param schedulingQuantum The interval between scheduling cycles.
          */
         public operator fun invoke(
             context: CoroutineContext,
             clock: Clock,
-            meter: Meter,
+            meterProvider: MeterProvider,
             scheduler: ComputeScheduler,
-            schedulingQuantum: Long = 300000,
+            schedulingQuantum: Duration = Duration.ofMinutes(5),
         ): ComputeService {
-            return ComputeServiceImpl(context, clock, meter, scheduler, schedulingQuantum)
+            return ComputeServiceImpl(context, clock, meterProvider, scheduler, schedulingQuantum)
         }
     }
 }
diff --git a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/ComputeServiceImpl.kt b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/ComputeServiceImpl.kt
index f1c055d4..824becf4 100644
--- a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/ComputeServiceImpl.kt
+++ b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/ComputeServiceImpl.kt
@@ -22,9 +22,8 @@
 
 package org.opendc.compute.service.internal
 
-import io.opentelemetry.api.common.Attributes
 import io.opentelemetry.api.metrics.Meter
-import io.opentelemetry.semconv.resource.attributes.ResourceAttributes
+import io.opentelemetry.api.metrics.MeterProvider
 import kotlinx.coroutines.*
 import mu.KotlinLogging
 import org.opendc.compute.api.*
@@ -35,6 +34,7 @@ import org.opendc.compute.service.driver.HostState
 import org.opendc.compute.service.scheduler.ComputeScheduler
 import org.opendc.utils.TimerScheduler
 import java.time.Clock
+import java.time.Duration
 import java.util.*
 import kotlin.coroutines.CoroutineContext
 import kotlin.math.max
@@ -42,15 +42,18 @@ import kotlin.math.max
 /**
  * Internal implementation of the OpenDC Compute service.
  *
- * @param context The [CoroutineContext] to use.
- * @param clock The clock instance to keep track of time.
+ * @param context The [CoroutineContext] to use in the service.
+ * @param clock The clock instance to use.
+ * @param meterProvider The [MeterProvider] for creating a [Meter] for the service.
+ * @param scheduler The scheduler implementation to use.
+ * @param schedulingQuantum The interval between scheduling cycles.
  */
 internal class ComputeServiceImpl(
     private val context: CoroutineContext,
     private val clock: Clock,
-    private val meter: Meter,
+    meterProvider: MeterProvider,
     private val scheduler: ComputeScheduler,
-    private val schedulingQuantum: Long
+    private val schedulingQuantum: Duration
 ) : ComputeService, HostListener {
     /**
      * The [CoroutineScope] of the service bounded by the lifecycle of the service.
@@ -63,6 +66,11 @@ internal class ComputeServiceImpl(
     private val logger = KotlinLogging.logger {}
 
     /**
+     * The [Meter] to track metrics of the [ComputeService].
+     */
+    private val meter = meterProvider.get("org.opendc.compute.service")
+
+    /**
      * The [Random] instance used to generate unique identifiers for the objects.
      */
     private val random = Random(0)
@@ -365,10 +373,12 @@ internal class ComputeServiceImpl(
             return
         }
 
+        val quantum = schedulingQuantum.toMillis()
+
         // We assume that the provisioner runs at a fixed slot every time quantum (e.g t=0, t=60, t=120).
         // This is important because the slices of the VMs need to be aligned.
         // We calculate here the delay until the next scheduling slot.
-        val delay = schedulingQuantum - (clock.millis() % schedulingQuantum)
+        val delay = quantum - (clock.millis() % quantum)
 
         timerScheduler.startSingleTimer(Unit, delay) {
             doSchedule()
@@ -414,7 +424,7 @@ internal class ComputeServiceImpl(
             // Remove request from queue
             queue.poll()
             _waitingServers.add(-1)
-            _schedulerDuration.record(now - request.submitTime, Attributes.of(ResourceAttributes.HOST_ID, server.uid.toString()))
+            _schedulerDuration.record(now - request.submitTime, server.attributes)
 
             logger.info { "Assigned server $server to host $host." }
 
diff --git a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/InternalServer.kt b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/InternalServer.kt
index d9d0f3fc..05a7e1bf 100644
--- a/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/InternalServer.kt
+++ b/opendc-compute/opendc-compute-service/src/main/kotlin/org/opendc/compute/service/internal/InternalServer.kt
@@ -22,6 +22,9 @@
 
 package org.opendc.compute.service.internal
 
+import io.opentelemetry.api.common.AttributeKey
+import io.opentelemetry.api.common.Attributes
+import io.opentelemetry.semconv.resource.attributes.ResourceAttributes
 import mu.KotlinLogging
 import org.opendc.compute.api.*
 import org.opendc.compute.service.driver.Host
@@ -50,6 +53,21 @@ internal class InternalServer(
     private val watchers = mutableListOf<ServerWatcher>()
 
     /**
+     * The attributes of a server.
+     */
+    internal val attributes: Attributes = Attributes.builder()
+        .put(ResourceAttributes.HOST_NAME, name)
+        .put(ResourceAttributes.HOST_ID, uid.toString())
+        .put(ResourceAttributes.HOST_TYPE, flavor.name)
+        .put(AttributeKey.longKey("host.num_cpus"), flavor.cpuCount.toLong())
+        .put(AttributeKey.longKey("host.mem_capacity"), flavor.memorySize)
+        .put(AttributeKey.stringArrayKey("host.labels"), labels.map { (k, v) -> "$k:$v" })
+        .put(ResourceAttributes.HOST_ARCH, ResourceAttributes.HostArchValues.AMD64)
+        .put(ResourceAttributes.HOST_IMAGE_NAME, image.name)
+        .put(ResourceAttributes.HOST_IMAGE_ID, image.uid.toString())
+        .build()
+
+    /**
      * The [Host] that has been assigned to host the server.
      */
     internal var host: Host? = null
diff --git a/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/ComputeServiceTest.kt b/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/ComputeServiceTest.kt
index d036ec00..564f9493 100644
--- a/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/ComputeServiceTest.kt
+++ b/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/ComputeServiceTest.kt
@@ -61,8 +61,7 @@ internal class ComputeServiceTest {
             filters = listOf(ComputeFilter(), VCpuFilter(allocationRatio = 1.0), RamFilter(allocationRatio = 1.0)),
             weighers = listOf(RamWeigher())
         )
-        val meter = MeterProvider.noop().get("opendc-compute")
-        service = ComputeService(scope.coroutineContext, clock, meter, computeScheduler)
+        service = ComputeService(scope.coroutineContext, clock, MeterProvider.noop(), computeScheduler)
     }
 
     @Test
diff --git a/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/InternalServerTest.kt b/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/InternalServerTest.kt
index 28fd8217..dfd3bc67 100644
--- a/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/InternalServerTest.kt
+++ b/opendc-compute/opendc-compute-service/src/test/kotlin/org/opendc/compute/service/InternalServerTest.kt
@@ -47,8 +47,9 @@ class InternalServerTest {
     fun testEquality() {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
+
         val a = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
         val b = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
@@ -59,8 +60,8 @@ class InternalServerTest {
     fun testEqualityWithDifferentType() {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val a = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         val b = mockk<Server>(relaxUnitFun = true)
@@ -73,8 +74,8 @@ class InternalServerTest {
     fun testInequalityWithDifferentType() {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val a = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         val b = mockk<Server>(relaxUnitFun = true)
@@ -87,8 +88,8 @@ class InternalServerTest {
     fun testInequalityWithIncorrectType() {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val a = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         assertNotEquals(a, Unit)
@@ -98,8 +99,8 @@ class InternalServerTest {
     fun testStartTerminatedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         every { service.schedule(any()) } answers { ComputeServiceImpl.SchedulingRequest(it.invocation.args[0] as InternalServer, 0) }
@@ -114,8 +115,8 @@ class InternalServerTest {
     fun testStartDeletedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.DELETED
@@ -127,8 +128,8 @@ class InternalServerTest {
     fun testStartProvisioningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.PROVISIONING
@@ -142,8 +143,8 @@ class InternalServerTest {
     fun testStartRunningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.RUNNING
@@ -157,8 +158,8 @@ class InternalServerTest {
     fun testStopProvisioningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
         val request = ComputeServiceImpl.SchedulingRequest(server, 0)
 
@@ -175,8 +176,8 @@ class InternalServerTest {
     fun testStopTerminatedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.TERMINATED
@@ -189,8 +190,8 @@ class InternalServerTest {
     fun testStopDeletedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.DELETED
@@ -203,8 +204,8 @@ class InternalServerTest {
     fun testStopRunningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>()
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
         val host = mockk<Host>(relaxUnitFun = true)
 
@@ -220,8 +221,8 @@ class InternalServerTest {
     fun testDeleteProvisioningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>(relaxUnitFun = true)
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
         val request = ComputeServiceImpl.SchedulingRequest(server, 0)
 
@@ -239,8 +240,8 @@ class InternalServerTest {
     fun testDeleteTerminatedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>(relaxUnitFun = true)
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.TERMINATED
@@ -255,8 +256,8 @@ class InternalServerTest {
     fun testDeleteDeletedServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>(relaxUnitFun = true)
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
 
         server.state = ServerState.DELETED
@@ -269,8 +270,8 @@ class InternalServerTest {
     fun testDeleteRunningServer() = runBlockingSimulation {
         val service = mockk<ComputeServiceImpl>(relaxUnitFun = true)
         val uid = UUID.randomUUID()
-        val flavor = mockk<InternalFlavor>()
-        val image = mockk<InternalImage>()
+        val flavor = mockFlavor()
+        val image = mockImage()
         val server = InternalServer(service, uid, "test", flavor, image, mutableMapOf(), mutableMapOf())
         val host = mockk<Host>(relaxUnitFun = true)
 
@@ -282,4 +283,20 @@ class InternalServerTest {
         coVerify { host.delete(server) }
         verify { service.delete(server) }
     }
+
+    private fun mockFlavor(): InternalFlavor {
+        val flavor = mockk<InternalFlavor>()
+        every { flavor.name } returns "c5.large"
+        every { flavor.uid } returns UUID.randomUUID()
+        every { flavor.cpuCount } returns 2
+        every { flavor.memorySize } returns 4096
+        return flavor
+    }
+
+    private fun mockImage(): InternalImage {
+        val image = mockk<InternalImage>()
+        every { image.name } returns "ubuntu-20.04"
+        every { image.uid } returns UUID.randomUUID()
+        return image
+    }
 }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
index a1cc3390..be6ef11e 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
@@ -25,6 +25,7 @@ package org.opendc.compute.simulator
 import io.opentelemetry.api.common.AttributeKey
 import io.opentelemetry.api.common.Attributes
 import io.opentelemetry.api.metrics.Meter
+import io.opentelemetry.api.metrics.MeterProvider
 import io.opentelemetry.semconv.resource.attributes.ResourceAttributes
 import kotlinx.coroutines.*
 import mu.KotlinLogging
@@ -59,7 +60,7 @@ public class SimHost(
     override val meta: Map<String, Any>,
     context: CoroutineContext,
     interpreter: SimResourceInterpreter,
-    private val meter: Meter,
+    meterProvider: MeterProvider,
     hypervisor: SimHypervisorProvider,
     scalingGovernor: ScalingGovernor = PerformanceScalingGovernor(),
     powerDriver: PowerDriver = SimplePowerDriver(ConstantPowerModel(0.0)),
@@ -82,6 +83,11 @@ public class SimHost(
     private val logger = KotlinLogging.logger {}
 
     /**
+     * The [Meter] to track metrics of the simulated host.
+     */
+    private val meter = meterProvider.get("org.opendc.compute.simulator")
+
+    /**
      * The event listeners registered with this host.
      */
     private val listeners = mutableListOf<HostListener>()
@@ -142,10 +148,9 @@ public class SimHost(
      * The total number of guests.
      */
     private val _guests = meter.upDownCounterBuilder("guests.total")
-        .setDescription("Number of guests")
+        .setDescription("Total number of guests")
         .setUnit("1")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The number of active guests on the host.
@@ -154,7 +159,6 @@ public class SimHost(
         .setDescription("Number of active guests")
         .setUnit("1")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The CPU demand of the host.
@@ -163,7 +167,6 @@ public class SimHost(
         .setDescription("The amount of CPU resources the guests would use if there were no CPU contention or CPU limits")
         .setUnit("MHz")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The CPU usage of the host.
@@ -172,7 +175,6 @@ public class SimHost(
         .setDescription("The amount of CPU resources used by the host")
         .setUnit("MHz")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The power usage of the host.
@@ -181,7 +183,6 @@ public class SimHost(
         .setDescription("The amount of power used by the CPU")
         .setUnit("W")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The total amount of work supplied to the CPU.
@@ -191,7 +192,6 @@ public class SimHost(
         .setUnit("1")
         .ofDoubles()
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The work performed by the CPU.
@@ -201,7 +201,6 @@ public class SimHost(
         .setUnit("1")
         .ofDoubles()
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The amount not performed by the CPU due to overcommitment.
@@ -211,7 +210,6 @@ public class SimHost(
         .setUnit("1")
         .ofDoubles()
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The amount of work not performed by the CPU due to interference.
@@ -221,7 +219,6 @@ public class SimHost(
         .setUnit("1")
         .ofDoubles()
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The amount of time in the system.
@@ -230,7 +227,6 @@ public class SimHost(
         .setDescription("The amount of time in the system")
         .setUnit("ms")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The uptime of the host.
@@ -239,7 +235,6 @@ public class SimHost(
         .setDescription("The uptime of the host")
         .setUnit("ms")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     /**
      * The downtime of the host.
@@ -248,7 +243,6 @@ public class SimHost(
         .setDescription("The downtime of the host")
         .setUnit("ms")
         .build()
-        .bind(Attributes.of(ResourceAttributes.HOST_ID, uid.toString()))
 
     init {
         // Launch hypervisor onto machine
@@ -391,13 +385,28 @@ public class SimHost(
         var state: ServerState = ServerState.TERMINATED
 
         /**
+         * The attributes of the guest.
+         */
+        val attributes: Attributes = Attributes.builder()
+            .put(ResourceAttributes.HOST_NAME, server.name)
+            .put(ResourceAttributes.HOST_ID, server.uid.toString())
+            .put(ResourceAttributes.HOST_TYPE, server.flavor.name)
+            .put(AttributeKey.longKey("host.num_cpus"), server.flavor.cpuCount.toLong())
+            .put(AttributeKey.longKey("host.mem_capacity"), server.flavor.memorySize)
+            .put(AttributeKey.stringArrayKey("host.labels"), server.labels.map { (k, v) -> "$k:$v" })
+            .put(ResourceAttributes.HOST_ARCH, ResourceAttributes.HostArchValues.AMD64)
+            .put(ResourceAttributes.HOST_IMAGE_NAME, server.image.name)
+            .put(ResourceAttributes.HOST_IMAGE_ID, server.image.uid.toString())
+            .build()
+
+        /**
          * The amount of time in the system.
          */
         private val _totalTime = meter.counterBuilder("guest.time.total")
             .setDescription("The amount of time in the system")
             .setUnit("ms")
             .build()
-            .bind(Attributes.of(AttributeKey.stringKey("server.id"), server.uid.toString()))
+            .bind(attributes)
 
         /**
          * The uptime of the guest.
@@ -406,7 +415,7 @@ public class SimHost(
             .setDescription("The uptime of the guest")
             .setUnit("ms")
             .build()
-            .bind(Attributes.of(AttributeKey.stringKey("server.id"), server.uid.toString()))
+            .bind(attributes)
 
         /**
          * The time the guest is in an error state.
@@ -415,7 +424,7 @@ public class SimHost(
             .setDescription("The time the guest is in an error state")
             .setUnit("ms")
             .build()
-            .bind(Attributes.of(AttributeKey.stringKey("server.id"), server.uid.toString()))
+            .bind(attributes)
 
         suspend fun start() {
             when (state) {
diff --git a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
index 9fa8af34..318b5a5d 100644
--- a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
+++ b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
@@ -49,6 +49,7 @@ import org.opendc.telemetry.sdk.toOtelClock
 import java.time.Duration
 import java.util.*
 import kotlin.coroutines.resume
+import kotlin.math.roundToLong
 
 /**
  * Basic test-suite for the hypervisor.
@@ -72,7 +73,7 @@ internal class SimHostTest {
      */
     @Test
     fun testOvercommitted() = runBlockingSimulation {
-        var requestedWork = 0L
+        var totalWork = 0L
         var grantedWork = 0L
         var overcommittedWork = 0L
 
@@ -89,7 +90,7 @@ internal class SimHostTest {
             meta = emptyMap(),
             coroutineContext,
             interpreter,
-            meterProvider.get("opendc-compute-simulator"),
+            meterProvider,
             SimFairShareHypervisorProvider()
         )
         val duration = 5 * 60L
@@ -134,15 +135,10 @@ internal class SimHostTest {
             object : MetricExporter {
                 override fun export(metrics: Collection<MetricData>): CompletableResultCode {
                     val metricsByName = metrics.associateBy { it.name }
-                    metricsByName["cpu.work.total"]?.let {
-                        requestedWork = it.doubleSumData.points.sumOf { point -> point.value }.toLong()
-                    }
-                    metricsByName["cpu.work.granted"]?.let {
-                        grantedWork = it.doubleSumData.points.sumOf { point -> point.value }.toLong()
-                    }
-                    metricsByName["cpu.work.overcommit"]?.let {
-                        overcommittedWork = it.doubleSumData.points.sumOf { point -> point.value }.toLong()
-                    }
+
+                    totalWork = metricsByName.getValue("cpu.work.total").doubleSumData.points.first().value.roundToLong()
+                    grantedWork = metricsByName.getValue("cpu.work.granted").doubleSumData.points.first().value.roundToLong()
+                    overcommittedWork = metricsByName.getValue("cpu.work.overcommit").doubleSumData.points.first().value.roundToLong()
                     return CompletableResultCode.ofSuccess()
                 }
 
@@ -176,7 +172,7 @@ internal class SimHostTest {
         reader.close()
 
         assertAll(
-            { assertEquals(4147200, requestedWork, "Requested work does not match") },
+            { assertEquals(4147200, totalWork, "Requested work does not match") },
             { assertEquals(2107200, grantedWork, "Granted work does not match") },
             { assertEquals(2040000, overcommittedWork, "Overcommitted work does not match") },
             { assertEquals(1500001, clock.millis()) }
@@ -188,7 +184,7 @@ internal class SimHostTest {
      */
     @Test
     fun testFailure() = runBlockingSimulation {
-        var requestedWork = 0L
+        var totalWork = 0L
         var grantedWork = 0L
         var totalTime = 0L
         var downTime = 0L
@@ -208,7 +204,7 @@ internal class SimHostTest {
             meta = emptyMap(),
             coroutineContext,
             interpreter,
-            meterProvider.get("opendc-compute-simulator"),
+            meterProvider,
             SimFairShareHypervisorProvider()
         )
         val duration = 5 * 60L
@@ -237,24 +233,14 @@ internal class SimHostTest {
             object : MetricExporter {
                 override fun export(metrics: Collection<MetricData>): CompletableResultCode {
                     val metricsByName = metrics.associateBy { it.name }
-                    metricsByName["cpu.work.total"]?.let {
-                        requestedWork = it.doubleSumData.points.sumOf { point -> point.value }.toLong()
-                    }
-                    metricsByName["cpu.work.granted"]?.let {
-                        grantedWork = it.doubleSumData.points.sumOf { point -> point.value }.toLong()
-                    }
-                    metricsByName["host.time.total"]?.let {
-                        totalTime = it.longSumData.points.first().value
-                    }
-                    metricsByName["host.time.down"]?.let {
-                        downTime = it.longSumData.points.first().value
-                    }
-                    metricsByName["guest.time.total"]?.let {
-                        guestTotalTime = it.longSumData.points.first().value
-                    }
-                    metricsByName["guest.time.error"]?.let {
-                        guestDownTime = it.longSumData.points.first().value
-                    }
+
+                    totalWork = metricsByName.getValue("cpu.work.total").doubleSumData.points.first().value.roundToLong()
+                    grantedWork = metricsByName.getValue("cpu.work.granted").doubleSumData.points.first().value.roundToLong()
+                    totalTime = metricsByName.getValue("host.time.total").longSumData.points.first().value
+                    downTime = metricsByName.getValue("host.time.down").longSumData.points.first().value
+                    guestTotalTime = metricsByName.getValue("guest.time.total").longSumData.points.first().value
+                    guestDownTime = metricsByName.getValue("guest.time.error").longSumData.points.first().value
+
                     return CompletableResultCode.ofSuccess()
                 }
 
@@ -290,8 +276,8 @@ internal class SimHostTest {
         reader.close()
 
         assertAll(
-            { assertEquals(2226039, requestedWork, "Total time does not match") },
-            { assertEquals(1086039, grantedWork, "Down time does not match") },
+            { assertEquals(2226040, totalWork, "Total time does not match") },
+            { assertEquals(1086040, grantedWork, "Down time does not match") },
             { assertEquals(1200001, totalTime, "Total time does not match") },
             { assertEquals(1200001, guestTotalTime, "Guest total time does not match") },
             { assertEquals(5000, downTime, "Down time does not match") },