Monitoring YARN Application Execution
Monitoring the execution of YARN applications is crucial for ensuring the efficient and reliable operation of your Hadoop cluster. In this section, we will explore various approaches and techniques for monitoring YARN application execution.
YARN Resource Manager Web UI
The YARN Resource Manager provides a web-based user interface that allows you to monitor the execution of YARN applications. To access the YARN Resource Manager web UI, follow these steps:
- Open a web browser and navigate to
http://<resource-manager-host>:8088
.
- The YARN Resource Manager web UI will be displayed, showing information about running applications, cluster resources, and more.
The YARN Resource Manager web UI offers the following key features for monitoring application execution:
- Application List: View a list of all running and completed applications, along with their status, progress, and resource utilization.
- Application Details: Drill down into the details of a specific application, including its containers, logs, and resource usage.
- Node Manager Status: Monitor the status and resource utilization of individual YARN nodes.
- Cluster Metrics: View overall cluster-level metrics, such as available resources, used resources, and application throughput.
YARN provides a set of command-line tools that can be used to monitor application execution. Here are some of the most commonly used YARN CLI tools:
yarn application
: Retrieve information about running and completed applications.
yarn node
: Retrieve information about YARN nodes and their resource utilization.
yarn logs
: Retrieve the logs of a specific YARN application or container.
Here's an example of how to use the yarn application
command to retrieve information about a running application:
$ yarn application -status <application-id>
This command will display detailed information about the specified application, including its status, progress, and resource utilization.
YARN REST API
The YARN Resource Manager exposes a REST API that allows you to programmatically access application and cluster-level metrics. This can be particularly useful for integrating YARN monitoring into custom applications or third-party monitoring tools.
To use the YARN REST API, you can make HTTP requests to the appropriate endpoints. For example, to retrieve information about a running application, you can use the following REST API endpoint:
GET http://<resource-manager-host>:8088/ws/v1/cluster/apps/<application-id>
The response from this API call will contain detailed information about the specified application, which you can then use to monitor its execution.
By leveraging the YARN Resource Manager web UI, CLI tools, and REST API, you can effectively monitor the execution of YARN applications and ensure the overall health and performance of your Hadoop cluster.