Yarn Log Overview

Log Description

The default paths for saving Yarn logs are as follows:

  • ResourceManager: /var/log/Bigdata/yarn/rm (run logs) and /var/log/Bigdata/audit/yarn/rm (audit logs)

  • NodeManager: /var/log/Bigdata/yarn/nm (run logs) and /var/log/Bigdata/audit/yarn/nm (audit logs)

Log archive rule: The automatic compression and archive function is enabled for Yarn logs. By default, when the size of a log file exceeds 50 MB, the log file is automatically compressed. The naming rule of the compressed log file is as follows: <Original log file name>-<yyyy-mm-dd_hh-mm-ss>.[ID].log.zip. A maximum of 100 latest compressed files are retained. The number of compressed files can be configured on Manager.

Log archive rule:

Table 1 Yarn log list

Log Type

Log File Name

Description

Run log

hadoop-<SSH_USER>-<process_name>-<hostname>.log

Yarn component log file, which records most of the logs generated when the Yarn component is running

yarn-<SSH_USER>-<process_name>-<hostname>.out

Log file that records Yarn running environment information

<process_name>-<SSH_USER>-<DATE>-<PID>-gc.log

Garbage collection log file

yarn-haCheck.log

ResourceManager active/standby status detection log file

yarn-service-check.log

Log file that records the health check details of the Yarn service

yarn-start-stop.log

Log file that records the startup and stop of the Yarn service

yarn-prestart.log

Log file that records cluster operations before the Yarn service startup

yarn-postinstall.log

Work log file after installation and before startup of the Yarn service

hadoop-commission.log

Yarn service entry log file

yarn-cleanup.log

Log file that records the cleanup operation during uninstallation of the Yarn service

yarn-refreshqueue.log

Yarn queue refresh log file

upgradeDetail.log

Upgrade log file

stderr/stdin/syslog

Container log file of the applications running on the Yarn service

yarn-application-check.log

Check log file of applications running on the Yarn service

yarn-appsummary.log

Running result log file of applications running on the Yarn service

yarn-switch-resourcemanager.log

Run log file that records the Yarn active/standby switchover

ranger-yarn-plugin-enable.log

Log file that records the enabling of Ranger authentication for Yarn

yarn-nodemanager-period-check.log

Periodic check log of Yarn NodeManager

yarn-resourcemanager-period-check.log

Periodic check log of Yarn ResourceManager

hadoop.log

Hadoop client logs

env.log

Environment information log file before the instance is started or stopped.

Audit logs

yarn-audit-<process_name>.log

ranger-plugin-audit.log

Yarn operation audit log file

SecurityAuth.audit

Yarn security audit log file

Log Level

Table 2 describes the log levels supported by Yarn, including OFF, FATAL, ERROR, WARN, INFO, and DEBUG, from high priority to low. Logs whose levels are higher than or equal to the specified level are printed. The number of printed logs decreases as the specified log level increases.

Table 2 Log levels

Level

Description

FATAL

Logs of this level record critical error information about the current event processing.

ERROR

Logs of this level record error information about the current event processing.

WARN

Logs of this level record exception information about the current event processing.

INFO

Logs of this level record normal running status information about the system and events.

DEBUG

Logs of this level record the system as well as system debugging information.

To modify log levels, perform the following operations:

  1. Go to the All Configurations page of the Yarn service by referring to Modifying Cluster Service Configuration Parameters.

  2. On the menu bar on the left, select the log menu of the target role.

  3. Select a desired log level.

  4. Click Save Configuration. In the dialog box that is displayed, click OK to make the setting take effect.

    Note

    The configurations take effect immediately without the need to restart the service.

Log Format

The following table lists the Yarn log formats.

Table 3 Log formats

Log Type

Format

Example

Run log

<yyyy-MM-dd HH:mm:ss,SSS>|<Log Level>|<Thread that generates the log>|<Message in the log>|<Location of the log event>

2014-09-26 14:18:59,109 | INFO | main | Client environment:java.compiler=<NA> | org.apache.zookeeper.Environment.logEnv(Environment.java:100)

Audit log

<yyyy-MM-dd HH:mm:ss,SSS>|<Log Level>|<Thread that generates the log>|<Message in the log>|<Location of the log event>

2014-09-26 14:24:43,605 | INFO | main-EventThread | USER=omm OPERATION=refreshAdminAcls TARGET=AdminService RESULT=SUCCESS | org.apache.hadoop.yarn.server.resourcemanager.RMAuditLogger$LogLevel$6.printLog(RMAuditLogger.java:91)