下載jmx_exporter的jar包

https://repo1.maven.org/maven2/io/prometheus/jmx/jmx_prometheus_javaagent/0.3.1/jmx_prometheus_javaagent-0.3.1.jar

創建配置文件namenode.yaml(datanode.yaml)放在任意位置，內容爲你想要的metrics

參考配置：

---
startDelaySeconds: 0
hostPort: master:1234 #master爲本機IP（一般可設置爲localhost）；1234爲想設置的jmx端口（可設置爲未被佔用的端口）
#jmxUrl: service:jmx:rmi:///jndi/rmi://127.0.0.1:1234/jmxrmi
ssl: false
lowercaseOutputName: false
lowercaseOutputLabelNames: false

其他參數參考：

Name	Description
startDelaySeconds	start delay before serving requests. Any requests within the delay period will result in an empty metrics set.
hostPort	The host and port to connect to via remote JMX. If neither this nor jmxUrl is specified, will talk to the local JVM.
username	The username to be used in remote JMX password authentication.
password	The password to be used in remote JMX password authentication.
jmxUrl	A full JMX URL to connect to. Should not be specified if hostPort is.
ssl	Whether JMX connection should be done over SSL. To configure certificates you have to set following system properties: `-Djavax.net.ssl.keyStore=/home/user/.keystore` `-Djavax.net.ssl.keyStorePassword=changeit` `-Djavax.net.ssl.trustStore=/home/user/.truststore` `-Djavax.net.ssl.trustStorePassword=changeit`
lowercaseOutputName	Lowercase the output metric name. Applies to default format and `name`. Defaults to false.
lowercaseOutputLabelNames	Lowercase the output metric label names. Applies to default format and `labels`. Defaults to false.
whitelistObjectNames	A list of ObjectNames to query. Defaults to all mBeans.
blacklistObjectNames	A list of ObjectNames to not query. Takes precedence over `whitelistObjectNames`. Defaults to none.
rules	A list of rules to apply in order, processing stops at the first matching rule. Attributes that aren't matched aren't collected. If not specified, defaults to collecting everything in the default format.
pattern	Regex pattern to match against each bean attribute. The pattern is not anchored. Capture groups can be used in other options. Defaults to matching everything.
attrNameSnakeCase	Converts the attribute name to snake case. This is seen in the names matched by the pattern and the default format. For example, anAttrName to an_attr_name. Defaults to false.
name	The metric name to set. Capture groups from the `pattern` can be used. If not specified, the default format will be used. If it evaluates to empty, processing of this attribute stops with no output.
value	Value for the metric. Static values and capture groups from the `pattern` can be used. If not specified the scraped mBean value will be used.
valueFactor	Optional number that `value` (or the scraped mBean value if `value` is not specified) is multiplied by, mainly used to convert mBean values from milliseconds to seconds.
labels	A map of label name to label value pairs. Capture groups from `pattern` can be used in each. `name` must be set to use this. Empty names and values are ignored. If not specified and the default format is not being used, no labels are set.
help	Help text for the metric. Capture groups from `pattern` can be used. `name` must be set to use this. Defaults to the mBean attribute decription and the full name of the attribute.
type	The type of the metric, can be `GAUGE`, `COUNTER` or `UNTYPED`. `name` must be set to use this. Defaults to `UNTYPED`.

修改$HADOOP_HOME/etc/hadoop/hadoop-env.sh

NameNode節點添加：

export HADOOP_NAMENODE_OPTS="-Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.local.only=false   -Dcom.sun.management.jmxremote.port=1234 $HADOOP_NAMENODE_OPTS "

DataNode節點添加：

export HADOOP_DATANODE_OPTS="-Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.local.only=false   -Dcom.sun.management.jmxremote.port=1235 $HADOOP_DATANODE_OPTS "

提示：

端口1234（1235）要與之前設置的jmx端口保持一致

修改 (路徑根據實際位置寫)

$HADOOP_HOME/bin/hdfs

export HADOOP_NAMENODE_OPTS="$HADOOP_NAMENODE_OPTS -javaagent:/home/hadoop/jmx_prometheus_javaagent-0.3.1.jar=9200:/home/hadoop/namenode.yaml"

export HADOOP_DATANODE_OPTS="$HADOOP_DATANODE_OPTS -javaagent:/home/hadoop/jmx_prometheus_javaagent-0.3.1.jar=9300:/home/hadoop/datanode.yaml"

提示：9200（9300）爲jmx_exporter提供metrics數據端口，後續Prometheus從此端口獲取數據

訪問http://master:9200/metrics就能獲得需要的metrics數據:

# HELP jvm_buffer_pool_used_bytes Used bytes of a given JVM buffer pool.
# TYPE jvm_buffer_pool_used_bytes gauge
jvm_buffer_pool_used_bytes{pool="direct",} 1181032.0
jvm_buffer_pool_used_bytes{pool="mapped",} 0.0
# HELP jvm_buffer_pool_capacity_bytes Bytes capacity of a given JVM buffer pool.
# TYPE jvm_buffer_pool_capacity_bytes gauge
jvm_buffer_pool_capacity_bytes{pool="direct",} 1181032.0
jvm_buffer_pool_capacity_bytes{pool="mapped",} 0.0
# HELP jvm_buffer_pool_used_buffers Used buffers of a given JVM buffer pool.
...

下載Prometheus

https://prometheus.io/download/

解壓

修改配置文件 prometheus.yml

添加

  - job_name: hadoop-master

    static_configs:
      - targets: ['localhost:9200']

  - job_name: hadoop-slave1

    static_configs:
      - targets: ['slave1:9300']

運行