Using the YARN CLI to viewlogs for applications

Use the YARN CLI to view logs for running application. Configure the log aggregation to aggregate and write out logs for all containers belonging to a single Application grouped by NodeManagers to single log files at a configured location in the file system.

You can access container log files using the YARN ResourceManager web UI, but more options are available when you use the yarn logs CLI command.

View all log files for an application

Use the following command format to view all logs for an application:

yarn logs -applicationId <Application ID>

View a specific log type for an application

Use the following command format to view all logs of a particular type for an application:

yarn logs -applicationId <Application ID> -log_files <log_file_type>

For example, to view only the stderr error logs:

yarn logs -applicationId <Application ID> -log_files stderr

The -logFiles option also supports Java regular expressions, so the following format would return all types of log files:

yarn logs -applicationId <Application ID> -log_files .*

View ApplicationMaster log files

Use the following command format to view all ApplicationMaster container log files for an application:

yarn logs -applicationId <Application ID> -am ALL

Use the following command format to view only the first ApplicationMaster container log files:

yarn logs -applicationId <Application ID> -am 1

List container IDs

Use the following command format to list all container IDs for an application:

yarn logs -applicationId <Application ID> -show_application_log_info

View log files for one container

Once you have the container IDs, you can use the following command format to list the log files for a particular container:

yarn logs -applicationId <Application ID> -containerId <Container ID>

Show container log file information

Use the following command format to list all of the container log file names (types) for an application:

yarn logs -applicationId <Application ID> -show_container_log_info

You can then use the -logFiles option to view a particular log type.

View a portion of the log files for one container

For large container log files, you can use the following command format to list only a portion of the log files for a particular container:

yarn logs -applicationId <Application ID> -containerId <Container ID> -size <bytes>

To view the first 1000 bytes:

yarn logs -applicationId <Application ID> -containerId <Container ID> -size 1000

To view the last 1000 bytes:

yarn logs -applicationId <Application ID> -containerId <Container ID> -size -1000

Download logs for an application

Use the following command format to download logs to a local folder:

yarn logs -applicationId <Application ID> -out <path_to_local_folder>

The container log files are organized in parent folders labeled with the applicable node ID.

Display help for YARN logs

To display Help for yarn logs, run the following command:

yarn logs -help