[feature]add apache hdfs monitoring

home/docs/help/hdfs_datanode.md

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+---
+id: hdfs_datanode
+title: Monitoring Apache HDFS DataNode Monitoring
+sidebar_label: Apache HDFS DataNode
+keywords: [big data monitoring system, distributed file system monitoring, Apache HDFS DataNode monitoring]
+---
+
+> Hertzbeat monitors metrics for Apache HDFS DataNode nodes.
+
+**Protocol Used: HTTP**
+
+## Pre-monitoring Operations
+
+Retrieve the HTTP monitoring port for the Apache HDFS DataNode. Value: `dfs.datanode.http.address`
+
+## Configuration Parameters
+
+| Parameter Name    | Parameter Description                                 |
+| ----------------- |-------------------------------------------------------|
+| Target Host       | IP(v4 or v6) or domain name of the target to be monitored. Exclude protocol. |
+| Port              | Monitoring port number for Apache HDFS DataNode, default is 50075. |
+| Query Timeout     | Timeout for querying Apache HDFS DataNode, in milliseconds, default is 6000 milliseconds. |
+| Metrics Collection Interval | Time interval for monitoring data collection, in seconds, minimum interval is 30 seconds. |
+| Probe Before Monitoring | Whether to probe and check monitoring availability before adding. |
+| Description/Remarks | Additional description and remarks for this monitoring. |
+
+### Metrics Collected
+
+#### Metric Set: FSDatasetState
+
+| Metric Name  | Metric Unit | Metric Description              |
+| ------------ | ----------- | ------------------------------ |
+| DfsUsed      | GB          | DataNode HDFS usage            |
+| Remaining    | GB          | Remaining space on DataNode HDFS |
+| Capacity     | GB          | Total capacity of DataNode HDFS |
+
+#### Metric Set: JvmMetrics
+
+| Metric Name            | Metric Unit | Metric Description                        |
+| ---------------------- | ----------- | ----------------------------------------- |
+| MemNonHeapUsedM        | MB          | Current usage of NonHeapMemory by JVM     |
+| MemNonHeapCommittedM   | MB          | Committed size of NonHeapMemory configured in JVM |
+| MemHeapUsedM           | MB          | Current usage of HeapMemory by JVM         |
+| MemHeapCommittedM      | MB          | Committed size of HeapMemory by JVM        |
+| MemHeapMaxM            | MB          | Maximum size of HeapMemory configured in JVM |
+| MemMaxM                | MB          | Maximum memory available for JVM at runtime |
+| ThreadsRunnable        | Count       | Number of threads in RUNNABLE state       |
+| ThreadsBlocked         | Count       | Number of threads in BLOCKED state        |
+| ThreadsWaiting         | Count       | Number of threads in WAITING state        |
+| ThreadsTimedWaiting    | Count       | Number of threads in TIMED WAITING state  |
+
+#### Metric Set: runtime
+
+| Metric Name  | Metric Unit | Metric Description |
+| ------------ | ----------- | ------------------ |
+| StartTime    |             | Startup time       |