Add MetricsServlet for Spark metrics system

1 files changed, 17 insertions, 6 deletions

diff --git a/conf/metrics.properties.template b/conf/metrics.properties.template
index 63a5a2093e..07fd046539 100644
--- a/conf/metrics.properties.template
+++ b/conf/metrics.properties.template
@@ -3,8 +3,8 @@
 #  This file configures Spark's internal metrics system. The metrics system is
 #  divided into instances which correspond to internal components.
 #  Each instance can be configured to report its metrics to one or more sinks.
-#  Accepted values for [instance] are "master", "worker", "executor", "driver", 
-#  and "applications". A wild card "*" can be used as an instance name, in 
+#  Accepted values for [instance] are "master", "worker", "executor", "driver",
+#  and "applications". A wild card "*" can be used as an instance name, in
 #  which case all instances will inherit the supplied property.
 #
 #  Within an instance, a "source" specifies a particular set of grouped metrics.
@@ -19,7 +19,7 @@
 #  A "sink" specifies where metrics are delivered to. Each instance can be
 #  assigned one or more sinks.
 #
-#  The sink|source field specifies whether the property relates to a sink or 
+#  The sink|source field specifies whether the property relates to a sink or
 #  source.
 #
 #  The [name] field specifies the name of source or sink.
@@ -28,18 +28,29 @@
 #  source or sink is responsible for parsing this property.
 #
 #  Notes:
-#    1. To add a new sink, set the "class" option to a fully qualified class 
+#    1. To add a new sink, set the "class" option to a fully qualified class
 #    name (see examples below).
 #    2. Some sinks involve a polling period. The minimum allowed polling period
 #    is  1 second.
-#    3. Wild card properties can be overridden by more specific properties. 
-#    For example, master.sink.console.period takes precedence over 
+#    3. Wild card properties can be overridden by more specific properties.
+#    For example, master.sink.console.period takes precedence over
 #    *.sink.console.period.
 #    4. A metrics specific configuration
 #    "spark.metrics.conf=${SPARK_HOME}/conf/metrics.properties" should be
 #    added to Java properties using -Dspark.metrics.conf=xxx if you want to
 #    customize metrics system. You can also put the file in ${SPARK_HOME}/conf
 #    and it will be loaded automatically.
+#    5. MetricsServlet is added by default as a sink in master, worker and client
+#    driver, you can send http request "/metrics" to get a snapshot of all the
+#    registered metrics in json format. For master, requests "/metrics/master" and
+#    "/metrics/applications" can be sent seperately to get metrics snapshot of
+#    instance master and applications.
+#
+
+# Change MetricsServlet's property
+#*.sink.servlet.uri=/metrics
+#
+#*.sink.servlet.sample=false
 
 # Enable JmxSink for all instances by class name
 #*.sink.jmx.class=spark.metrics.sink.JmxSink