Why does my yarn application not have logs even with logging enabled? Why does my yarn application not have logs even with logging enabled? hadoop hadoop

Why does my yarn application not have logs even with logging enabled?


yarn application -list

will list only the applications that are either in SUBMITTED, ACCEPTED or RUNNING state.

Log aggregation collects each container's logs and moves these logs onto the directory configured in yarn.nodemanager.remote-app-log-dir only after the completion of the application. Refer the description of yarn.log-aggregation-enable property here.

So, the applicationId listed by the command isn't completed yet and the logs are not yet collected. Thus the response when trying to access the logs of a running application

hdfs://<ip address>/var/log/hadoop-yarn/path/to/application/  does not have any log files

You can try the same command yarn logs -applicationId <application ID> to view the logs once the application has completed.

To list all the FINISHED applications, use

yarn application -list -appStates FINISHED

Or to list all the applications

yarn application -list -appStates ALL


Enable Log Aggregation

Log aggregation is enabled in the yarn-site.xml file. The yarn.log-aggregation-enable property enables log aggregation for running applications.

<property> <name>yarn.log-aggregation-enable</name> <value>true</value></property>


In version 2.3.2 of hadoop and higher you can get log aggregation to occur hourly on running jobs using this configuration in yarn-site.xml:

<property>    <name>yarn.nodemanager.log-aggregation.roll-monitoring-interval-seconds</name>    <value>3600</value></property>

See this for further details: https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.3.2/bk_yarn_resource_mgt/content/ref-375ff479-e530-46d8-9f96-8b52dadb5183.1.html