Added API to pass custom Prometheus configuration file contained in a…

… job image; automatically truncate the volume name to fit 63 chars

docs/api.md

@@ -1,11 +1,7 @@
 # SparkApplication API
 
-The Kubernetes Operator for Apache Spark uses  [CustomResourceDefinitions](https://kubernetes.io/docs/concepts/api-extension/custom-resources/) 
-named `SparkApplication` and `ScheduledSparkApplication` for specifying one-time Spark applications and Spark applications
-that are supposed to run on a standard [cron](https://en.wikipedia.org/wiki/Cron) schedule. Similarly to other kinds of 
-Kubernetes resources, they consist of a specification in a `Spec` field and a `Status` field. The definitions are organized 
-in the following structure. The v1beta1 version of the API definition is implemented 
-[here](../pkg/apis/sparkoperator.k8s.io/v1beta1/types.go).
+The Kubernetes Operator for Apache Spark uses  [CustomResourceDefinitions](https://kubernetes.io/docs/concepts/api-extension/custom-resources/) named `SparkApplication` and `ScheduledSparkApplication` for specifying one-time Spark applications and Spark applications
+that are supposed to run on a standard [cron](https://en.wikipedia.org/wiki/Cron) schedule. Similarly to other kinds of Kubernetes resources, they consist of a specification in a `Spec` field and a `Status` field. The definitions are organized in the following structure. The v1beta1 version of the API definition is implemented [here](../pkg/apis/sparkoperator.k8s.io/v1beta1/types.go).
 
 ```
 ScheduledSparkApplication
@@ -124,7 +120,8 @@ A `PrometheusSpec` configures how metrics are exposed to Prometheus.
 | ------------- | ------------- | ------------- |
 | `JmxExporterJar` | N/A | This specifies the path to the [Prometheus JMX exporter](https://github.com/prometheus/jmx_exporter) jar. |
 | `Port` | N/A | If specified, the value will be used in the Java agent configuration for the Prometheus JMX exporter. The Java agent gets bound to the specified port if specified or `8090` otherwise by default. |
-| `Configuration` | N/A | If specified, this contains the content of a custom Prometheus configuration used by the Prometheus JMX exporter. Otherwise, the content of `spark-docker/conf/prometheus.yaml` will be used. |
+| `ConfigFile` | N/A | This specifies the full path of the Prometheus configuration file in the Spark job image. If specified, it will override the default configurations and take precedence over `Configuration` shown below. |
+| `Configuration` | N/A | If specified, this contains the contents of a custom Prometheus configuration used by the Prometheus JMX exporter. Otherwise, the contents of `spark-docker/conf/prometheus.yaml` will be used, unless `ConfigFile` is specified. |
 
 ### `SparkApplicationStatus`
 

pkg/apis/sparkoperator.k8s.io/v1beta1/types.go

@@ -478,8 +478,12 @@ type PrometheusSpec struct {
 	// Optional.
 	// If not specified, 8090 will be used as the default.
 	Port *int32 `json:"port"`
+	// ConfigFile is the path to the custom Prometheus configuration file provided in the Spark job image.
+	// ConfigFile takes precedence over Configuration, which is shown below.
+	ConfigFile string `json:"configFile"`
 	// Configuration is the content of the Prometheus configuration needed by the Prometheus JMX exporter.
 	// Optional.
 	// If not specified, the content in spark-docker/conf/prometheus.yaml will be used.
+	// Configuration has no effect if ConfigFile is set.
 	Configuration *string `json:"configuration"`
 }

pkg/controller/sparkapplication/monitoring_config.go

@@ -18,6 +18,7 @@ package sparkapplication
 
 import (
 	"fmt"
+	"github.com/golang/glog"
 	corev1 "k8s.io/api/core/v1"
 	apiErrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -39,26 +40,55 @@ const (
 )
 
 func configPrometheusMonitoring(app *v1beta1.SparkApplication, kubeClient clientset.Interface) error {
-	prometheusConfigMapName := fmt.Sprintf("%s-%s", app.Name, prometheusConfigMapNameSuffix)
-	configMap := buildPrometheusConfigMap(app, prometheusConfigMapName)
-	retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
-		cm, err := kubeClient.CoreV1().ConfigMaps(app.Namespace).Get(prometheusConfigMapName, metav1.GetOptions{})
-
-		if apiErrors.IsNotFound(err) {
-			_, createErr := kubeClient.CoreV1().ConfigMaps(app.Namespace).Create(configMap)
-			return createErr
-		}
-		if err != nil {
-			return err
-		}
+	port := config.DefaultPrometheusJavaAgentPort
+	if app.Spec.Monitoring.Prometheus.Port != nil {
+		port = *app.Spec.Monitoring.Prometheus.Port
+	}
 
-		cm.Data = configMap.Data
-		_, updateErr := kubeClient.CoreV1().ConfigMaps(app.Namespace).Update(cm)
-		return updateErr
-	})
+	configFile := app.Spec.Monitoring.Prometheus.ConfigFile
+	var javaOption string
+	if configFile != "" {
+		glog.V(2).Infof("Overriding the default Prometheus configuration with config file %s in the Spark job image.", configFile)
+		javaOption = fmt.Sprintf("-javaagent:%s=%d:%s", app.Spec.Monitoring.Prometheus.JmxExporterJar,
+			port, configFile)
+	} else {
+		glog.V(2).Infof("Using the default Prometheus configuration.")
+		prometheusConfigMapName := fmt.Sprintf("%s-%s", app.Name, prometheusConfigMapNameSuffix)
+		configMap := buildPrometheusConfigMap(app, prometheusConfigMapName)
+		retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
+			cm, err := kubeClient.CoreV1().ConfigMaps(app.Namespace).Get(prometheusConfigMapName, metav1.GetOptions{})
+
+			if apiErrors.IsNotFound(err) {
+				_, createErr := kubeClient.CoreV1().ConfigMaps(app.Namespace).Create(configMap)
+				return createErr
+			}
+			if err != nil {
+				return err
+			}
+
+			cm.Data = configMap.Data
+			_, updateErr := kubeClient.CoreV1().ConfigMaps(app.Namespace).Update(cm)
+			return updateErr
+		})
 
-	if retryErr != nil {
-		return fmt.Errorf("failed to apply %s in namespace %s: %v", prometheusConfigMapName, app.Namespace, retryErr)
+		if retryErr != nil {
+			return fmt.Errorf("failed to apply %s in namespace %s: %v", prometheusConfigMapName, app.Namespace, retryErr)
+		}
+		javaOption = fmt.Sprintf("-javaagent:%s=%d:%s/%s", app.Spec.Monitoring.Prometheus.JmxExporterJar,
+			port, prometheusConfigMapMountPath, prometheusConfigKey)
+
+		if app.Spec.Monitoring.ExposeDriverMetrics {
+			app.Spec.Driver.ConfigMaps = append(app.Spec.Driver.ConfigMaps, v1beta1.NamePath{
+				Name: prometheusConfigMapName,
+				Path: prometheusConfigMapMountPath,
+			})
+		}
+		if app.Spec.Monitoring.ExposeExecutorMetrics {
+			app.Spec.Executor.ConfigMaps = append(app.Spec.Executor.ConfigMaps, v1beta1.NamePath{
+				Name: prometheusConfigMapName,
+				Path: prometheusConfigMapMountPath,
+			})
+		}
 	}
 
 	/* work around for push gateway issue: https://github.com/prometheus/pushgateway/issues/97 */
@@ -70,19 +100,7 @@ func configPrometheusMonitoring(app *v1beta1.SparkApplication, kubeClient client
 	app.Spec.SparkConf["spark.metrics.namespace"] = metricNamespace
 	app.Spec.SparkConf["spark.metrics.conf"] = metricConf
 
-	port := config.DefaultPrometheusJavaAgentPort
-	if app.Spec.Monitoring.Prometheus.Port != nil {
-		port = *app.Spec.Monitoring.Prometheus.Port
-	}
-	javaOption := fmt.Sprintf("-javaagent:%s=%d:%s/%s", app.Spec.Monitoring.Prometheus.JmxExporterJar,
-		port, prometheusConfigMapMountPath, prometheusConfigKey)
-
 	if app.Spec.Monitoring.ExposeDriverMetrics {
-		app.Spec.Driver.ConfigMaps = append(app.Spec.Driver.ConfigMaps, v1beta1.NamePath{
-			Name: prometheusConfigMapName,
-			Path: prometheusConfigMapMountPath,
-		})
-
 		if app.Spec.Driver.Annotations == nil {
 			app.Spec.Driver.Annotations = make(map[string]string)
 		}
@@ -97,11 +115,6 @@ func configPrometheusMonitoring(app *v1beta1.SparkApplication, kubeClient client
 		}
 	}
 	if app.Spec.Monitoring.ExposeExecutorMetrics {
-		app.Spec.Executor.ConfigMaps = append(app.Spec.Executor.ConfigMaps, v1beta1.NamePath{
-			Name: prometheusConfigMapName,
-			Path: prometheusConfigMapMountPath,
-		})
-
 		if app.Spec.Executor.Annotations == nil {
 			app.Spec.Executor.Annotations = make(map[string]string)
 		}

pkg/webhook/patch.go

@@ -18,6 +18,7 @@ package webhook
 
 import (
 	"fmt"
+	"github.com/golang/glog"
 
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -29,6 +30,7 @@ import (
 const (
 	sparkDriverContainerName   = "spark-kubernetes-driver"
 	sparkExecutorContainerName = "executor"
+	maxNameLength              = 63
 )
 
 // patchOperation represents a RFC6902 JSON patch operation.
@@ -206,6 +208,11 @@ func addGeneralConfigMaps(pod *corev1.Pod) []*patchOperation {
 	namesToMountPaths := config.FindGeneralConfigMaps(pod.Annotations)
 	for name, mountPath := range namesToMountPaths {
 		volumeName := name + "-vol"
+		if len(volumeName) > maxNameLength {
+			glog.V(2).Infof("ConfigMap volume name %s is too long. Truncating to length %d.", volumeName, maxNameLength)
+			volumeName = volumeName[0:maxNameLength]
+			glog.V(2).Infof("Truncated volume name: %s.", volumeName)
+		}
 		patchOps = append(patchOps, addConfigMapVolume(pod, name, volumeName))
 		patchOps = append(patchOps, addConfigMapVolumeMount(pod, volumeName, mountPath))
 	}