Project: Druid (App Definition and Development / Database)
File: ambari-metrics-emitter.md

id: ambari-metrics-emitter title: "Ambari Metrics Emitter" <!-- ~ Licensed to the Apache Software Foundation (ASF) under one ~ or more contributor license agreements. See the NOTICE file ~ distributed with this work for additional information ~ regarding copyright ownership. The ASF licenses this file ~ to you under the Apache License, Version 2.0 (the ~ "License"); you may not use this file except in compliance ~ with the License. You may obtain a copy of the License at ~ ~ http://www.apache.org/licenses/LICENSE-2.0 ~ ~ Unless required by applicable law or agreed to in writing, ~ software distributed under the License is distributed on an ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY ~ KIND, either express or implied. See the License for the ~ specific language governing permissions and limitations ~ under the License. --> To use this Apache Druid extension, `ambari-metrics-emitter` in the extensions load list. This extension emits Druid metrics to an ambari-metrics carbon server. Events are sent after been pickled (i.e., batched). The size of the batch is configurable. All the configuration parameters for ambari-metrics emitter are under `druid.emitter.ambari-metrics`. |property|description|required?|default| |--|--||-| |`druid.emitter.ambari-metrics.hostname`|The hostname of the ambari-metrics server.|yes|none| |`druid.emitter.ambari-metrics.port`|The port of the ambari-metrics server.|yes|none| |`druid.emitter.ambari-metrics.protocol`|The protocol used to send metrics to ambari metrics collector. One of http/https|no|http| |`druid.emitter.ambari-metrics.trustStorePath`|Path to trustStore to be used for https|no|none| |`druid.emitter.ambari-metrics.trustStoreType`|trustStore type to be used for https|no|none| |`druid.emitter.ambari-metrics.trustStoreType`|trustStore password to be used for https|no|none| |`druid.emitter.ambari-metrics.batchSize`|Number of events to send as one batch.|no|100| |`druid.emitter.ambari-metrics.eventConverter`| Filter and converter of druid events to ambari-metrics timeline event(please see next section). |yes|none| |`druid.emitter.ambari-metrics.flushPeriod` | Queue flushing period in milliseconds. |no|1 minute| |`druid.emitter.ambari-metrics.maxQueueSize`| Maximum size of the queue used to buffer events. |no|`MAX_INT`| |`druid.emitter.ambari-metrics.alertEmitters`| List of emitters where alerts will be forwarded to. |no| empty list (no forwarding)| |`druid.emitter.ambari-metrics.emitWaitTime` | wait time in milliseconds to try to send the event otherwise emitter will throwing event. |no|0| |`druid.emitter.ambari-metrics.waitForEventTime` | waiting time in milliseconds if necessary for an event to become available. |no|1000 (1 sec)| Ambari Metrics Timeline Event Converter defines a mapping between druid metrics name plus dimensions to a timeline event metricName. ambari-metrics metric path is organized using the following schema: `<namespacePrefix>.[<druid service name>].[<druid hostname>].<druid metrics dimensions>.<druid metrics name>` Properly naming the metrics is critical to avoid conflicts, confusing data and potentially wrong interpretation later on. Example `druid.historical.hist-host1:8080.MyDataSourceName.GroupBy.query/time`: `druid` -> namespace prefix `historical` -> service name `hist-host1:8080` -> druid hostname `MyDataSourceName` -> dimension value `GroupBy` -> dimension value `query/time` -> metric name We have two different implementation of event converter: The first implementation called `all`, will send all the druid service metrics events. The path will be in the form `<namespacePrefix>.[<druid service name>].[<druid hostname>].<dimensions values ordered by dimension's name>.<metric>` User has control of `<namespacePrefix>.[<druid service name>].[<druid hostname>].` ```json druid.emitter.ambari-metrics.eventConverter={"type":"all", "namespacePrefix": "druid.test", "appName":"druid"} ``` The second implementation called `whiteList`, will send only the white listed metrics and dimensions. Same as for the `all` converter user has control of `<namespacePrefix>.[<druid service name>].[<druid hostname>].` White-list based converter comes with the following default white list map located under resources in `./src/main/resources/defaultWhiteListMap.json` Although user can override the default white list map by supplying a property called `mapPath`. This property is a String containing the path for the file containing white list map JSON object. For example the following converter will read the map from the file `/pathPrefix/fileName.json`. ```json druid.emitter.ambari-metrics.eventConverter={"type":"whiteList", "namespacePrefix": "druid.test", "ignoreHostname":true, "appName":"druid", "mapPath":"/pathPrefix/fileName.json"} ``` Druid emits a huge number of metrics we highly recommend to use the `whiteList` converter