https://www.jianshu.com/p/b9245242472b
https://stackoverflow.com/questions/42637631/what-does-virtual-core-in-yarn-vcore-mean
https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.6.5/bk_yarn-resource-management/content/enabling_cgroups.html
https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.6.5/bk_yarn-resource-management/content/using_cgroups.html
http://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/NodeManagerCgroups.html
https://developer.ibm.com/hadoop/2017/06/30/deep-dive-yarn-cgroups/
https://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/FairScheduler.html
Chapter 11. Using the YARN CLI to View Logs for Running Applications
This chapter describes how to use the YARN CLI (Command Line Interface) to view log files for running applications. 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 a Running Application
Use the following command format to view all logs for a running application:
yarn logs -applicationId <Application ID>
View a Specific Log Type for a Running Application
Use the following command format to view all logs of a particular type for a running 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 a running application:
yarn logs -applicationId <Application ID> -am ALL
Use the following command format to view only the first ApplicationMaster containter log files:
yarn logs -applicationId <Application ID> -am 1
List Container IDs
Use the following command format to list all container IDs for a running 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 a running 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 a Running 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 commmand:
yarn logs -help
Commands for testing¶
These operations are here primarily for testing.
kill-container <name> --id container-id
Kill a YARN container belong to the application. This is useful primarily for testing the resilience to failures.
Container IDs can be determined from the application instance status JSON document.
