[SPARK-22994][k8s] Use a single image for all Spark containers.

This change allows a user to submit a Spark application on kubernetes
having to provide a single image, instead of one image for each type
of container. The image's entry point now takes an extra argument that
identifies the process that is being started.

The configuration still allows the user to provide different images
for each container type if they so desire.

On top of that, the entry point was simplified a bit to share more
code; mainly, the same env variable is used to propagate the user-defined
classpath to the different containers.

Aside from being modified to match the new behavior, the
'build-push-docker-images.sh' script was renamed to 'docker-image-tool.sh'
to more closely match its purpose; the old name was a little awkward
and now also not entirely correct, since there is a single image. It
was also moved to 'bin' since it's not necessarily an admin tool.

Docs and scripts have been updated to match the new behavior.

Author: Marcelo Vanzin

sbin/build-push-docker-images.sh renamed to bin/docker-image-tool.sh

@@ -24,29 +24,11 @@ function error {
   exit 1
 }
 
-# Detect whether this is a git clone or a Spark distribution and adjust paths
-# accordingly.
 if [ -z "${SPARK_HOME}" ]; then
   SPARK_HOME="$(cd "`dirname "$0"`"/..; pwd)"
 fi
 . "${SPARK_HOME}/bin/load-spark-env.sh"
 
-if [ -f "$SPARK_HOME/RELEASE" ]; then
-  IMG_PATH="kubernetes/dockerfiles"
-  SPARK_JARS="jars"
-else
-  IMG_PATH="resource-managers/kubernetes/docker/src/main/dockerfiles"
-  SPARK_JARS="assembly/target/scala-$SPARK_SCALA_VERSION/jars"
-fi
-
-if [ ! -d "$IMG_PATH" ]; then
-  error "Cannot find docker images. This script must be run from a runnable distribution of Apache Spark."
-fi
-
-declare -A path=( [spark-driver]="$IMG_PATH/driver/Dockerfile" \
-                  [spark-executor]="$IMG_PATH/executor/Dockerfile" \
-                  [spark-init]="$IMG_PATH/init-container/Dockerfile" )
-
 function image_ref {
   local image="$1"
   local add_repo="${2:-1}"
@@ -60,35 +42,53 @@ function image_ref {
 }
 
 function build {
-  docker build \
-    --build-arg "spark_jars=$SPARK_JARS" \
-    --build-arg "img_path=$IMG_PATH" \
-    -t spark-base \
-    -f "$IMG_PATH/spark-base/Dockerfile" .
-  for image in "${!path[@]}"; do
-    docker build -t "$(image_ref $image)" -f ${path[$image]} .
-  done
+  # Detect whether this is a git clone or a Spark distribution and adjust paths
+  # accordingly.
+  local BUILD_ARGS
+  local IMG_PATH
+
+  if [ ! -f "$SPARK_HOME/RELEASE" ]; then
+    IMG_PATH=resource-managers/kubernetes/docker/src/main/dockerfiles
+    BUILD_ARGS=(
+      --build-arg
+      img_path=$IMG_PATH
+      --build-arg
+      spark_jars=assembly/target/scala-$SPARK_SCALA_VERSION/jars
+    )
+  else
+    # Not passed as an argument to docker, but used to validate the Spark directory.
+    IMG_PATH="kubernetes/dockerfiles"
+  fi
+
+  local DOCKERFILE=${DOCKERFILE:-"$IMG_PATH/spark/Dockerfile"}
+
+  if [ ! -d "$IMG_PATH" ]; then
+    error "Cannot find docker images. This script must be run from a runnable distribution of Apache Spark."
+  fi
+
+  docker build "${BUILD_ARGS[@]}" \
+    -t $(image_ref spark) \
+    -f "$DOCKERFILE" .
 }
 
 function push {
-  for image in "${!path[@]}"; do
-    docker push "$(image_ref $image)"
-  done
+  docker push "$(image_ref spark)"
 }
 
 function usage {
   cat <<EOF
 Usage: $0 [options] [command]
-Builds or pushes the built-in Spark Docker images.
+Builds or pushes the built-in Spark Docker image.
 
 Commands:
-  build       Build images.
-  push        Push images to a registry. Requires a repository address to be provided, both
-              when building and when pushing the images.
+  build       Build image.
+  push        Push a pre-built image to a registry. Requires a repository address to be provided,
+              both when building and when pushing the image.
 
 Options:
+  -f file     Dockerfile to build. By default builds the Dockerfile shipped with Spark.
   -r repo     Repository address.
-  -t tag      Tag to apply to built images, or to identify images to be pushed.
+  -t tag      Tag to apply to the built image, or to identify the image to be pushed.
   -m          Use minikube's Docker daemon.
 
 Using minikube when building images will do so directly into minikube's Docker daemon.
@@ -100,10 +100,10 @@ Check the following documentation for more information on using the minikube Doc
   https://kubernetes.io/docs/getting-started-guides/minikube/#reusing-the-docker-daemon
 
 Examples:
-  - Build images in minikube with tag "testing"
+  - Build image in minikube with tag "testing"
     $0 -m -t testing build
 
-  - Build and push images with tag "v2.3.0" to docker.io/myrepo
+  - Build and push image with tag "v2.3.0" to docker.io/myrepo
     $0 -r docker.io/myrepo -t v2.3.0 build
     $0 -r docker.io/myrepo -t v2.3.0 push
 EOF
@@ -116,10 +116,12 @@ fi
 
 REPO=
 TAG=
-while getopts mr:t: option
+DOCKERFILE=
+while getopts f:mr:t: option
 do
  case "${option}"
  in
+ f) DOCKERFILE=${OPTARG};;
  r) REPO=${OPTARG};;
  t) TAG=${OPTARG};;
  m)

docs/running-on-kubernetes.md

@@ -56,14 +56,13 @@ be run in a container runtime environment that Kubernetes supports. Docker is a
 frequently used with Kubernetes. With Spark 2.3, there are Dockerfiles provided in the runnable distribution that can be customized
 and built for your usage.
 
-You may build these docker images from sources.
-There is a script, `sbin/build-push-docker-images.sh` that you can use to build and push
-customized Spark distribution images consisting of all the above components.
+You may build these docker images from sources. Spark ships with a `bin/docker-image-tool.sh` script
+that can be used to build and publish the Spark Docker image to use with the Kubernetes backend.
 
 Example usage is:
 
-    ./sbin/build-push-docker-images.sh -r <repo> -t my-tag build
-    ./sbin/build-push-docker-images.sh -r <repo> -t my-tag push
+    ./bin/docker-image-tool.sh -r <repo> -t my-tag build
+    ./bin/docker-image-tool.sh -r <repo> -t my-tag push
 
 Docker files are under the `kubernetes/dockerfiles/` directory and can be customized further before
 building using the supplied script, or manually.
@@ -79,8 +78,7 @@ $ bin/spark-submit \
     --name spark-pi \
     --class org.apache.spark.examples.SparkPi \
     --conf spark.executor.instances=5 \
-    --conf spark.kubernetes.driver.container.image=<driver-image> \
-    --conf spark.kubernetes.executor.container.image=<executor-image> \
+    --conf spark.kubernetes.container.image=<spark-image> \
     local:///path/to/examples.jar
 ```
 
@@ -126,13 +124,7 @@ Those dependencies can be added to the classpath by referencing them with `local
 ### Using Remote Dependencies
 When there are application dependencies hosted in remote locations like HDFS or HTTP servers, the driver and executor pods
 need a Kubernetes [init-container](https://kubernetes.io/docs/concepts/workloads/pods/init-containers/) for downloading
-the dependencies so the driver and executor containers can use them locally. This requires users to specify the container
-image for the init-container using the configuration property `spark.kubernetes.initContainer.image`. For example, users
-simply add the following option to the `spark-submit` command to specify the init-container image:
-
-```
---conf spark.kubernetes.initContainer.image=<init-container image>
-```
+the dependencies so the driver and executor containers can use them locally.
 
 The init-container handles remote dependencies specified in `spark.jars` (or the `--jars` option of `spark-submit`) and
 `spark.files` (or the `--files` option of `spark-submit`). It also handles remotely hosted main application resources, e.g.,
@@ -147,9 +139,7 @@ $ bin/spark-submit \
     --jars https://path/to/dependency1.jar,https://path/to/dependency2.jar
     --files hdfs://host:port/path/to/file1,hdfs://host:port/path/to/file2
     --conf spark.executor.instances=5 \
-    --conf spark.kubernetes.driver.container.image=<driver-image> \
-    --conf spark.kubernetes.executor.container.image=<executor-image> \
-    --conf spark.kubernetes.initContainer.image=<init-container image>
+    --conf spark.kubernetes.container.image=<spark-image> \
     https://path/to/examples.jar
 ```
 
@@ -322,21 +312,27 @@ specific to Spark on Kubernetes.
   </td>
 </tr>
 <tr>
-  <td><code>spark.kubernetes.driver.container.image</code></td>
+  <td><code>spark.kubernetes.container.image</code></td>
   <td><code>(none)</code></td>
   <td>
-    Container image to use for the driver.
-    This is usually of the form <code>example.com/repo/spark-driver:v1.0.0</code>.
-    This configuration is required and must be provided by the user.
+    Container image to use for the Spark application.
+    This is usually of the form <code>example.com/repo/spark:v1.0.0</code>.
+    This configuration is required and must be provided by the user, unless explicit
+    images are provided for each different container type.
+  </td>
+</tr>
+<tr>
+  <td><code>spark.kubernetes.driver.container.image</code></td>
+  <td><code>(value of spark.kubernetes.container.image)</code></td>
+  <td>
+    Custom container image to use for the driver.
   </td>
 </tr>
 <tr>
   <td><code>spark.kubernetes.executor.container.image</code></td>
-  <td><code>(none)</code></td>
+  <td><code>(value of spark.kubernetes.container.image)</code></td>
   <td>
-    Container image to use for the executors.
-    This is usually of the form <code>example.com/repo/spark-executor:v1.0.0</code>.
-    This configuration is required and must be provided by the user.
+    Custom container image to use for executors.
   </td>
 </tr>
 <tr>
@@ -643,9 +639,9 @@ specific to Spark on Kubernetes.
 </tr>
 <tr>
   <td><code>spark.kubernetes.initContainer.image</code></td>
-  <td>(none)</td>
+  <td><code>(value of spark.kubernetes.container.image)</code></td>
   <td>
-   Container image for the <a href="https://kubernetes.io/docs/concepts/workloads/pods/init-containers/">init-container</a> of the driver and executors for downloading dependencies. This is usually of the form <code>example.com/repo/spark-init:v1.0.0</code>. This configuration is optional and must be provided by the user if any non-container local dependency is used and must be downloaded remotely.
+   Custom container image for the init container of both driver and executors.
   </td>
 </tr>
 <tr>

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Config.scala

@@ -29,17 +29,23 @@ private[spark] object Config extends Logging {
       .stringConf
       .createWithDefault("default")
 
+  val CONTAINER_IMAGE =
+    ConfigBuilder("spark.kubernetes.container.image")
+      .doc("Container image to use for Spark containers. Individual container types " +
+        "(e.g. driver or executor) can also be configured to use different images if desired, " +
+        "by setting the container-specific image name.")
+      .stringConf
+      .createOptional
+
   val DRIVER_CONTAINER_IMAGE =
     ConfigBuilder("spark.kubernetes.driver.container.image")
       .doc("Container image to use for the driver.")
-      .stringConf
-      .createOptional
+      .fallbackConf(CONTAINER_IMAGE)
 
   val EXECUTOR_CONTAINER_IMAGE =
     ConfigBuilder("spark.kubernetes.executor.container.image")
       .doc("Container image to use for the executors.")
-      .stringConf
-      .createOptional
+      .fallbackConf(CONTAINER_IMAGE)
 
   val CONTAINER_IMAGE_PULL_POLICY =
     ConfigBuilder("spark.kubernetes.container.image.pullPolicy")
@@ -148,8 +154,7 @@ private[spark] object Config extends Logging {
   val INIT_CONTAINER_IMAGE =
     ConfigBuilder("spark.kubernetes.initContainer.image")
       .doc("Image for the driver and executor's init-container for downloading dependencies.")
-      .stringConf
-      .createOptional
+      .fallbackConf(CONTAINER_IMAGE)
 
   val INIT_CONTAINER_MOUNT_TIMEOUT =
     ConfigBuilder("spark.kubernetes.mountDependencies.timeout")

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/Constants.scala

@@ -60,10 +60,9 @@ private[spark] object Constants {
   val ENV_APPLICATION_ID = "SPARK_APPLICATION_ID"
   val ENV_EXECUTOR_ID = "SPARK_EXECUTOR_ID"
   val ENV_EXECUTOR_POD_IP = "SPARK_EXECUTOR_POD_IP"
-  val ENV_EXECUTOR_EXTRA_CLASSPATH = "SPARK_EXECUTOR_EXTRA_CLASSPATH"
   val ENV_MOUNTED_CLASSPATH = "SPARK_MOUNTED_CLASSPATH"
   val ENV_JAVA_OPT_PREFIX = "SPARK_JAVA_OPT_"
-  val ENV_SUBMIT_EXTRA_CLASSPATH = "SPARK_SUBMIT_EXTRA_CLASSPATH"
+  val ENV_CLASSPATH = "SPARK_CLASSPATH"
   val ENV_DRIVER_MAIN_CLASS = "SPARK_DRIVER_CLASS"
   val ENV_DRIVER_ARGS = "SPARK_DRIVER_ARGS"
   val ENV_DRIVER_JAVA_OPTS = "SPARK_DRIVER_JAVA_OPTS"

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/InitContainerBootstrap.scala

@@ -77,6 +77,7 @@ private[spark] class InitContainerBootstrap(
         .withMountPath(INIT_CONTAINER_PROPERTIES_FILE_DIR)
         .endVolumeMount()
       .addToVolumeMounts(sharedVolumeMounts: _*)
+      .addToArgs("init")
       .addToArgs(INIT_CONTAINER_PROPERTIES_FILE_PATH)
       .build()
 

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/submit/steps/BasicDriverConfigurationStep.scala

@@ -66,7 +66,7 @@ private[spark] class BasicDriverConfigurationStep(
   override def configureDriver(driverSpec: KubernetesDriverSpec): KubernetesDriverSpec = {
     val driverExtraClasspathEnv = driverExtraClasspath.map { classPath =>
       new EnvVarBuilder()
-        .withName(ENV_SUBMIT_EXTRA_CLASSPATH)
+        .withName(ENV_CLASSPATH)
         .withValue(classPath)
         .build()
     }
@@ -133,6 +133,7 @@ private[spark] class BasicDriverConfigurationStep(
         .addToLimits("memory", driverMemoryLimitQuantity)
         .addToLimits(maybeCpuLimitQuantity.toMap.asJava)
         .endResources()
+      .addToArgs("driver")
       .build()
 
     val baseDriverPod = new PodBuilder(driverSpec.driverPod)

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/ExecutorPodFactory.scala

@@ -126,7 +126,7 @@ private[spark] class ExecutorPodFactory(
       .build()
     val executorExtraClasspathEnv = executorExtraClasspath.map { cp =>
       new EnvVarBuilder()
-        .withName(ENV_EXECUTOR_EXTRA_CLASSPATH)
+        .withName(ENV_CLASSPATH)
         .withValue(cp)
         .build()
     }
@@ -178,6 +178,7 @@ private[spark] class ExecutorPodFactory(
         .endResources()
       .addAllToEnv(executorEnv.asJava)
       .withPorts(requiredPorts.asJava)
+      .addToArgs("executor")
       .build()
 
     val executorPod = new PodBuilder()

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/submit/DriverConfigOrchestratorSuite.scala

@@ -34,8 +34,7 @@ class DriverConfigOrchestratorSuite extends SparkFunSuite {
   private val SECRET_MOUNT_PATH = "/etc/secrets/driver"
 
   test("Base submission steps with a main app resource.") {
-    val sparkConf = new SparkConf(false)
-      .set(DRIVER_CONTAINER_IMAGE, DRIVER_IMAGE)
+    val sparkConf = new SparkConf(false).set(CONTAINER_IMAGE, DRIVER_IMAGE)
     val mainAppResource = JavaMainAppResource("local:///var/apps/jars/main.jar")
     val orchestrator = new DriverConfigOrchestrator(
       APP_ID,
@@ -55,8 +54,7 @@ class DriverConfigOrchestratorSuite extends SparkFunSuite {
   }
 
   test("Base submission steps without a main app resource.") {
-    val sparkConf = new SparkConf(false)
-      .set(DRIVER_CONTAINER_IMAGE, DRIVER_IMAGE)
+    val sparkConf = new SparkConf(false).set(CONTAINER_IMAGE, DRIVER_IMAGE)
     val orchestrator = new DriverConfigOrchestrator(
       APP_ID,
       LAUNCH_TIME,
@@ -75,8 +73,8 @@ class DriverConfigOrchestratorSuite extends SparkFunSuite {
 
   test("Submission steps with an init-container.") {
     val sparkConf = new SparkConf(false)
-      .set(DRIVER_CONTAINER_IMAGE, DRIVER_IMAGE)
-      .set(INIT_CONTAINER_IMAGE, IC_IMAGE)
+      .set(CONTAINER_IMAGE, DRIVER_IMAGE)
+      .set(INIT_CONTAINER_IMAGE.key, IC_IMAGE)
       .set("spark.jars", "hdfs://localhost:9000/var/apps/jars/jar1.jar")
     val mainAppResource = JavaMainAppResource("local:///var/apps/jars/main.jar")
     val orchestrator = new DriverConfigOrchestrator(
@@ -98,7 +96,7 @@ class DriverConfigOrchestratorSuite extends SparkFunSuite {
 
   test("Submission steps with driver secrets to mount") {
     val sparkConf = new SparkConf(false)
-      .set(DRIVER_CONTAINER_IMAGE, DRIVER_IMAGE)
+      .set(CONTAINER_IMAGE, DRIVER_IMAGE)
       .set(s"$KUBERNETES_DRIVER_SECRETS_PREFIX$SECRET_FOO", SECRET_MOUNT_PATH)
       .set(s"$KUBERNETES_DRIVER_SECRETS_PREFIX$SECRET_BAR", SECRET_MOUNT_PATH)
     val mainAppResource = JavaMainAppResource("local:///var/apps/jars/main.jar")

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/submit/steps/BasicDriverConfigurationStepSuite.scala

@@ -47,7 +47,7 @@ class BasicDriverConfigurationStepSuite extends SparkFunSuite {
       .set(KUBERNETES_DRIVER_LIMIT_CORES, "4")
       .set(org.apache.spark.internal.config.DRIVER_MEMORY.key, "256M")
       .set(org.apache.spark.internal.config.DRIVER_MEMORY_OVERHEAD, 200L)
-      .set(DRIVER_CONTAINER_IMAGE, "spark-driver:latest")
+      .set(CONTAINER_IMAGE, "spark-driver:latest")
       .set(s"$KUBERNETES_DRIVER_ANNOTATION_PREFIX$CUSTOM_ANNOTATION_KEY", CUSTOM_ANNOTATION_VALUE)
       .set(s"$KUBERNETES_DRIVER_ENV_KEY$DRIVER_CUSTOM_ENV_KEY1", "customDriverEnv1")
       .set(s"$KUBERNETES_DRIVER_ENV_KEY$DRIVER_CUSTOM_ENV_KEY2", "customDriverEnv2")
@@ -79,7 +79,7 @@ class BasicDriverConfigurationStepSuite extends SparkFunSuite {
       .asScala
       .map(env => (env.getName, env.getValue))
       .toMap
-    assert(envs(ENV_SUBMIT_EXTRA_CLASSPATH) === "/opt/spark/spark-examples.jar")
+    assert(envs(ENV_CLASSPATH) === "/opt/spark/spark-examples.jar")
     assert(envs(ENV_DRIVER_MEMORY) === "256M")
     assert(envs(ENV_DRIVER_MAIN_CLASS) === MAIN_CLASS)
     assert(envs(ENV_DRIVER_ARGS) === "arg1 arg2 \"arg 3\"")

resource-managers/kubernetes/core/src/test/scala/org/apache/spark/deploy/k8s/submit/steps/initcontainer/InitContainerConfigOrchestratorSuite.scala

@@ -40,7 +40,7 @@ class InitContainerConfigOrchestratorSuite extends SparkFunSuite {
 
   test("including basic configuration step") {
     val sparkConf = new SparkConf(true)
-      .set(INIT_CONTAINER_IMAGE, DOCKER_IMAGE)
+      .set(CONTAINER_IMAGE, DOCKER_IMAGE)
       .set(s"$KUBERNETES_DRIVER_LABEL_PREFIX$CUSTOM_LABEL_KEY", CUSTOM_LABEL_VALUE)
 
     val orchestrator = new InitContainerConfigOrchestrator(
@@ -59,7 +59,7 @@ class InitContainerConfigOrchestratorSuite extends SparkFunSuite {
 
   test("including step to mount user-specified secrets") {
     val sparkConf = new SparkConf(false)
-      .set(INIT_CONTAINER_IMAGE, DOCKER_IMAGE)
+      .set(CONTAINER_IMAGE, DOCKER_IMAGE)
       .set(s"$KUBERNETES_DRIVER_SECRETS_PREFIX$SECRET_FOO", SECRET_MOUNT_PATH)
       .set(s"$KUBERNETES_DRIVER_SECRETS_PREFIX$SECRET_BAR", SECRET_MOUNT_PATH)