Solved

Where do syslog messages come from?

Posted on 2007-03-30
2
192 Views
Last Modified: 2013-12-16
Experts:

I am trying to learn about syslog (and syslog-ng).  I have a question:  Where do the log messages come from?  Does the kernel just spew messages all the time?  If logging is not configured, do the messages just go nowhere?  Does the programmer of a particular program decide the severity level (warn, info, etc) or does the system somehow classify the messages?  

For instance, as a programmer, can I just arbitrarily decide to send a log message classified as, say, daemon.warn?  Or am I limited to what types of messages I can send.  How would a program actually send a log message?  Would it use the "logger" command?

Thanks,
Tnic
Memphis TN
0
Comment
Question by:tayloenic
2 Comments
 
LVL 25

Expert Comment

by:Cyclops3590
ID: 18826030
0
 
LVL 48

Accepted Solution

by:
Tintin earned 125 total points
ID: 18834042
Lots of questions there.

1.  Log messages come from any program that does it's logging via syslog function call or via the command line 'logger' command.

2.  The Kernel will send out a variety of syslog messages. It depends on your syslog.conf configuration as to how much is actually recorded in log files.

3.  If syslogd is not running, or the syslog message doesn't match any of the syslog.conf entries, then it effectively gets binned.

4.  It's up to the programmer to decide what messages are debug, critical, notice, info etc.

5.  A programmer can use whatever facility and notice level they like for logging.  However, it is not a good idea to mix your logging with the standard existing syslog facilities.  LOCAL0 to LOCAL6 are reserved for custom apps, so you can log via them to keep the app logs separate from everything else.
0

Featured Post

Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Daily system administration tasks often require administrators to connect remote systems. But allowing these remote systems to accept passwords makes these systems vulnerable to the risk of brute-force password guessing attacks. Furthermore there ar…
Network Interface Card (NIC) bonding, also known as link aggregation, NIC teaming and trunking, is an important concept to understand and implement in any environment where high availability is of concern. Using this feature, a server administrator …
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

932 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

8 Experts available now in Live!

Get 1:1 Help Now