Hadoop Node Manager Health Test
The NodeManager is the per-machine slave, which is responsible for launching the applications’ containers, monitoring their resource usage (CPU, memory, disk, network), and reporting the same to the ResourceManager.
The NodeManager runs services to determine the health of the node it is executing on. The services perform checks on the disk as well as any user specified tests. If any health check fails, the NodeManager marks the node as unhealthy.
The Hadoop Node Manager Health test monitors the NodeManager on each slave node in a cluster, retrieves the results of the health checks the NodeManager performs on each node, and reports the current status of that node. This way, the test promptly alerts administrators to unhealthy nodes.
Target of the test : A Hadoop cluster
Agent deploying the test : A remote agent
Outputs of the test : One set of the results for each slave node in the cluster
| Parameter | Description |
|---|---|
|
Test Period |
How often should the test be executed. |
|
Host |
The IP address of the NameNode that processes client connections to the cluster. NameNode is the master node in the Apache Hadoop HDFS Architecture that maintains and manages the blocks present on the DataNodes (slave nodes). NameNode is a very highly available server that manages the File System Namespace and controls access to files by clients. |
|
Port |
The port at which the NameNode accepts client connections. NameNode is the master node in the Apache Hadoop HDFS Architecture that maintains and manages the blocks present on the DataNodes (slave nodes). NameNode is a very highly available server that manages the File System Namespace and controls access to files by clients. By default, the NameNode's client connection port is 8020. |
|
Name Node Web Port |
The eG agent collects metrics using Hadoop's WebHDFS REST API. While some of these API calls pull metrics from the NameNode, some others get metrics from the resource manager. NameNode is the master node in the Apache Hadoop HDFS Architecture that maintains and manages the blocks present on the DataNodes (slave nodes). NameNode is a very highly available server that manages the File System Namespace and controls access to files by clients. To run API commands on the NameNode and pull metrics, the eG agent needs access to the NameNode's web port. To determine the correct web port of the NameNode, do the following:
Configure the <Port_Number> in the specification as the Name Node Web Port. In the case of the above sample configuration, this will be 50070. |
|
Name Node User Name |
The eG agent collects metrics using Hadoop's WebHDFS REST API. While some of these API calls pull metrics from the NameNode, some others get metrics from the resource manager. NameNode is the master node in the Apache Hadoop HDFS Architecture that maintains and manages the blocks present on the DataNodes (slave nodes). NameNode is a very highly available server that manages the File System Namespace and controls access to files by clients. In some Hadoop configurations, a simple authentication user name may be required for running API commands and collecting metrics from the NameNode. When monitoring such Hadoop installations, specify the name of the simple authentication user here. If no such user is available/required, then do not disturb the default value none of this parameter. |
|
Resource Manager IP and Resource Manager Web Port |
The eG agent collects metrics using Hadoop's WebHDFS REST API. While some of these API calls pull metrics from the NameNode, some others get metrics from the resource manager. The YARN Resource Manager Service (RM) is the central controlling authority for resource management and makes resource allocation decisions. To pull metrics from the resource manager, the eG agents first needs to connect to the resource manager. For this, you need to configure this test with the IP address/host name of the resource manager and its web port. Use the Resource Manager IP and Resource Manager Web Port parameters to configure these details. To determine the IP/host name and web port of the resource manager, do the following:
Configure the <IP_Address_or_Host_Name> in the specification as the Resource Manager IP, and the <Port_Number> as the Resource Manager Web Port. In the case of the above sample configuration, this will be 8080. |
|
Resource Manager Username |
The eG agent collects metrics using Hadoop's WebHDFS REST API. While some of these API calls pull metrics from the NameNode, some others get metrics from the resource manager. The YARN Resource Manager Service (RM) is the central controlling authority for resource management and makes resource allocation decisions. In some Hadoop configurations, a simple authentication user name may be required for running API commands and collecting metrics from the resource manager. When monitoring such Hadoop installations, specify the name of the simple authentication user here. If no such user is available/required, then do not disturb the default value none of this parameter. |
| Measurement | Description | Measurement Unit | Interpretation | ||||||
|---|---|---|---|---|---|---|---|---|---|
|
Health status |
Indicates the health status of this node as reported by the NodeManager. |
|
The values that this measure reports and their corresponding numeric values are as follows:
Note: By default, this measure reports the Measure Values listed above to indicate how healthy a node is. In the graph of this measure however, the same is indicated using the numeric equivalents only. |
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|
Health status updated interval |
Indicates the time period (in seconds) that has elapsed since the last time the NodeManager on this node communicated the health status to the resource manager. |
Seconds |
Ideally, the value of this measure should be low. A high value indicates that the NodeManager has not reported the node status to the resource manager for a long time. This is a cause for concern, as it implies that there could be operational issues with the NodeManager. A thorough investigation is warranted. |
