Book Image

Monitoring Hadoop

By : Aman Singh
Book Image

Monitoring Hadoop

By: Aman Singh

Overview of this book

Table of Contents (14 chapters)

Logging levels


Every rule consists of two fields—selector field and action field. The selector field specifies a pattern of facilities and priority. Facility and priority is separated by a .; facility specifies the subsystem that produced the message. Table 1 lists out facilities and Table 2 lists out priorities:

Table 1: Facility

Facility

Description

Kernel

Kernel messages

User

User level messages

Mail

Mail messages

Daemon

System messages

FTP

FTP server messages

The log severity can be controlled using the priority option, and we can make it as verbose as we like. The trade off is always between size of logs and what to log.

Table 2: Priorities

Severity

Description

0

Emergency, system unstable

1

Alert: Immediate action

2

Critical: The state of the system/application is critical

3

Error condition: The system is throwing errors

4

Warning

7

Debug. Verbose logging of information

Log kernel-related messages to a separate file, with the pattern as kernel subsystem and...