diff --git a/docs/running-on-kubernetes.md b/docs/running-on-kubernetes.md index 037e1d54661e..0dc2cece9110 100644 --- a/docs/running-on-kubernetes.md +++ b/docs/running-on-kubernetes.md @@ -232,7 +232,19 @@ For example, the claim name of a `persistentVolumeClaim` with volume name `check spark.kubernetes.driver.volumes.persistentVolumeClaim.checkpointpvc.options.claimName=check-point-pvc-claim ``` -The configuration properties for mounting volumes into the executor pods use prefix `spark.kubernetes.executor.` instead of `spark.kubernetes.driver.`. For a complete list of available options for each supported type of volumes, please refer to the [Spark Properties](#spark-properties) section below. +The configuration properties for mounting volumes into the executor pods use prefix `spark.kubernetes.executor.` instead of `spark.kubernetes.driver.`. For a complete list of available options for each supported type of volumes, please refer to the [Spark Properties](#spark-properties) section below. + +## Local Storage + +Spark uses temporary scratch space to spill data to disk during shuffles and other operations. When using Kubernetes as the resource manager the pods will be created with an [emptyDir](https://kubernetes.io/docs/concepts/storage/volumes/#emptydir) volume mounted for each directory listed in `SPARK_LOCAL_DIRS`. If no directories are explicitly specified then a default directory is created and configured appropriately. + +`emptyDir` volumes use the ephemeral storage feature of Kubernetes and do not persist beyond the life of the pod. + +### Using RAM for local storage + +`emptyDir` volumes use the nodes backing storage for ephemeral storage by default, this behaviour may not be appropriate for some compute environments. For example if you have diskless nodes with remote storage mounted over a network, having lots of executors doing IO to this remote storage may actually degrade performance. + +In this case it may be desirable to set `spark.kubernetes.local.dirs.tmpfs=true` in your configuration which will cause the `emptyDir` volumes to be configured as `tmpfs` i.e. RAM backed volumes. When configured like this Sparks local storage usage will count towards your pods memory usage therefore you may wish to increase your memory requests by increasing the value of `spark.kubernetes.memoryOverheadFactor` as appropriate. ## Introspection and Debugging @@ -804,6 +816,14 @@ specific to Spark on Kubernetes. spark.kubernetes.executor.volumes.persistentVolumeClaim.checkpointpvc.options.claimName=spark-pvc-claim. + + spark.kubernetes.local.dirs.tmpfs + false + + Configure the emptyDir volumes used to back SPARK_LOCAL_DIRS within the Spark driver and executor pods to use tmpfs backing i.e. RAM. See Local Storage earlier on this page + for more discussion of this. + + spark.kubernetes.memoryOverheadFactor 0.1 diff --git a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala index c7338a721595..dea3b2886375 100644 --- a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala +++ b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala @@ -225,6 +225,15 @@ private[spark] object Config extends Logging { "Ensure that major Python version is either Python2 or Python3") .createWithDefault("2") + val KUBERNETES_LOCAL_DIRS_TMPFS = + ConfigBuilder("spark.kubernetes.local.dirs.tmpfs") + .doc("If set to true then emptyDir volumes created to back SPARK_LOCAL_DIRS will have " + + "their medium set to Memory so that they will be created as tmpfs (i.e. RAM) backed " + + "volumes. This may improve performance but scratch space usage will count towards " + + "your pods memory limit so you may wish to request more memory.") + .booleanConf + .createWithDefault(false) + val APP_RESOURCE_TYPE = ConfigBuilder("spark.kubernetes.resource.type") .doc("This sets the resource type internally") diff --git a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStep.scala b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStep.scala index 70b307303d14..346ca40ce35b 100644 --- a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStep.scala +++ b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStep.scala @@ -22,6 +22,7 @@ import java.util.UUID import io.fabric8.kubernetes.api.model.{ContainerBuilder, HasMetadata, PodBuilder, VolumeBuilder, VolumeMountBuilder} import org.apache.spark.deploy.k8s.{KubernetesConf, KubernetesDriverSpecificConf, KubernetesRoleSpecificConf, SparkPod} +import org.apache.spark.deploy.k8s.Config._ private[spark] class LocalDirsFeatureStep( conf: KubernetesConf[_ <: KubernetesRoleSpecificConf], @@ -37,6 +38,7 @@ private[spark] class LocalDirsFeatureStep( .orElse(conf.getOption("spark.local.dir")) .getOrElse(defaultLocalDir) .split(",") + private val useLocalDirTmpFs = conf.get(KUBERNETES_LOCAL_DIRS_TMPFS) override def configurePod(pod: SparkPod): SparkPod = { val localDirVolumes = resolvedLocalDirs @@ -45,6 +47,7 @@ private[spark] class LocalDirsFeatureStep( new VolumeBuilder() .withName(s"spark-local-dir-${index + 1}") .withNewEmptyDir() + .withMedium(if (useLocalDirTmpFs) "Memory" else null) .endEmptyDir() .build() } @@ -56,6 +59,7 @@ private[spark] class LocalDirsFeatureStep( .withMountPath(localDirPath) .build() } + val podWithLocalDirVolumes = new PodBuilder(pod.pod) .editSpec() .addToVolumes(localDirVolumes: _*) diff --git a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesDriverBuilder.scala b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesDriverBuilder.scala index 8f3f18ffadc3..44a6f8ba9564 100644 --- a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesDriverBuilder.scala +++ b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/KubernetesDriverBuilder.scala @@ -58,8 +58,7 @@ private[spark] class KubernetesDriverBuilder( val baseFeatures = Seq( provideBasicStep(kubernetesConf), provideCredentialsStep(kubernetesConf), - provideServiceStep(kubernetesConf), - provideLocalDirsStep(kubernetesConf)) + provideServiceStep(kubernetesConf)) val secretFeature = if (kubernetesConf.roleSecretNamesToMountPaths.nonEmpty) { Seq(provideSecretsStep(kubernetesConf)) @@ -70,6 +69,7 @@ private[spark] class KubernetesDriverBuilder( val volumesFeature = if (kubernetesConf.roleVolumes.nonEmpty) { Seq(provideVolumesStep(kubernetesConf)) } else Nil + val localDirsFeature = Seq(provideLocalDirsStep(kubernetesConf)) val bindingsStep = kubernetesConf.roleSpecificConf.mainAppResource.map { case JavaMainAppResource(_) => @@ -81,7 +81,7 @@ private[spark] class KubernetesDriverBuilder( .getOrElse(provideJavaStep(kubernetesConf)) val allFeatures = (baseFeatures :+ bindingsStep) ++ - secretFeature ++ envSecretFeature ++ volumesFeature + secretFeature ++ envSecretFeature ++ volumesFeature ++ localDirsFeature var spec = KubernetesDriverSpec.initialSpec(kubernetesConf.sparkConf.getAll.toMap) for (feature <- allFeatures) { diff --git a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesExecutorBuilder.scala b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesExecutorBuilder.scala index 364b6fb36772..e02974dbd63a 100644 --- a/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesExecutorBuilder.scala +++ b/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesExecutorBuilder.scala @@ -40,7 +40,7 @@ private[spark] class KubernetesExecutorBuilder( def buildFromFeatures( kubernetesConf: KubernetesConf[KubernetesExecutorSpecificConf]): SparkPod = { - val baseFeatures = Seq(provideBasicStep(kubernetesConf), provideLocalDirsStep(kubernetesConf)) + val baseFeatures = Seq(provideBasicStep(kubernetesConf)) val secretFeature = if (kubernetesConf.roleSecretNamesToMountPaths.nonEmpty) { Seq(provideSecretsStep(kubernetesConf)) } else Nil @@ -50,8 +50,10 @@ private[spark] class KubernetesExecutorBuilder( val volumesFeature = if (kubernetesConf.roleVolumes.nonEmpty) { Seq(provideVolumesStep(kubernetesConf)) } else Nil + val localDirsFeature = Seq(provideLocalDirsStep(kubernetesConf)) - val allFeatures = baseFeatures ++ secretFeature ++ secretEnvFeature ++ volumesFeature + val allFeatures = baseFeatures ++ secretFeature ++ secretEnvFeature ++ volumesFeature ++ + localDirsFeature var executorPod = SparkPod.initialPod() for (feature <- allFeatures) { diff --git a/resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStepSuite.scala b/resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStepSuite.scala index a339827b819a..b4ecfdfd46de 100644 --- a/resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStepSuite.scala +++ b/resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/features/LocalDirsFeatureStepSuite.scala @@ -21,7 +21,8 @@ import org.mockito.Mockito import org.scalatest.BeforeAndAfter import org.apache.spark.{SparkConf, SparkFunSuite} -import org.apache.spark.deploy.k8s.{KubernetesConf, KubernetesDriverSpecificConf, KubernetesRoleSpecificConf, SparkPod} +import org.apache.spark.deploy.k8s._ +import org.apache.spark.deploy.k8s.Config._ class LocalDirsFeatureStepSuite extends SparkFunSuite with BeforeAndAfter { private val defaultLocalDir = "/var/data/default-local-dir" @@ -111,4 +112,32 @@ class LocalDirsFeatureStepSuite extends SparkFunSuite with BeforeAndAfter { .withValue("/var/data/my-local-dir-1,/var/data/my-local-dir-2") .build()) } + + test("Use tmpfs to back default local dir") { + Mockito.doReturn(null).when(sparkConf).get("spark.local.dir") + Mockito.doReturn(null).when(sparkConf).getenv("SPARK_LOCAL_DIRS") + Mockito.doReturn(true).when(sparkConf).get(KUBERNETES_LOCAL_DIRS_TMPFS) + val stepUnderTest = new LocalDirsFeatureStep(kubernetesConf, defaultLocalDir) + val configuredPod = stepUnderTest.configurePod(SparkPod.initialPod()) + assert(configuredPod.pod.getSpec.getVolumes.size === 1) + assert(configuredPod.pod.getSpec.getVolumes.get(0) === + new VolumeBuilder() + .withName(s"spark-local-dir-1") + .withNewEmptyDir() + .withMedium("Memory") + .endEmptyDir() + .build()) + assert(configuredPod.container.getVolumeMounts.size === 1) + assert(configuredPod.container.getVolumeMounts.get(0) === + new VolumeMountBuilder() + .withName(s"spark-local-dir-1") + .withMountPath(defaultLocalDir) + .build()) + assert(configuredPod.container.getEnv.size === 1) + assert(configuredPod.container.getEnv.get(0) === + new EnvVarBuilder() + .withName("SPARK_LOCAL_DIRS") + .withValue(defaultLocalDir) + .build()) + } }