Examples — rsyslog 8.2412.0 documentation

# Examples

Below are example for templates and selector lines. I hope they are self-explanatory.

## Templates

Please note that the samples are split across multiple lines. A template MUST NOT actually be split across multiple lines.

A template that resembles traditional syslogd file output:

  $template TraditionalFormat,”%timegenerated% %HOSTNAME% %syslogtag%%msg:::drop-last-lf%\n”

A template that tells you a little more about the message:

  $template precise,”%syslogpriority%,%syslogfacility%,%timegenerated%,%HOSTNAME%, %syslogtag%,%msg%\n”

A template for RFC 3164 format:

  $template RFC3164fmt,”<%PRI%>%TIMESTAMP% %HOSTNAME% %syslogtag%%msg%”

A template for the format traditionally used for user messages:

  $template usermsg,” XXXX%syslogtag%%msg%\n\r”

And a template with the traditional wall-message format:

  $template wallmsg,”\r\n\7Message from syslogd@%HOSTNAME% at %timegenerated%

A template that can be used for the database write (please note the SQL template option)

  $template MySQLInsert,”insert iut, message, received at values (‘%iut%’, ‘%msg:::UPPERCASE%’, ‘%timegenerated:::date-mysql%’) into systemevents\r\n”, SQL

The following template emulates WinSyslog format (it’s an Adiscon format, you do not feel bad if you don’t know it ;)). It’s interesting to see how it takes different parts out of the date stamps. What happens is that the date stamp is split into the actual date and time and the these two are combined with just a comma in between them.

    $template WinSyslogFmt,"%HOSTNAME%,%timegenerated:1:10:date-rfc3339%,
    %timegenerated:12:19:date-rfc3339%,%timegenerated:1:10:date-rfc3339%,
    %timegenerated:12:19:date-rfc3339%,%syslogfacility%,%syslogpriority%,
    %syslogtag%%msg%\\n"

## Selector lines

    # Store critical stuff in critical
    #
    *.=crit;kern.none /var/adm/critical

This will store all messages with the priority crit in the file /var/adm/critical, except for any kernel message.

    # Kernel messages are first, stored in the kernel
    # file, critical messages and higher ones also go
    # to another host and to the console. Messages to
    # the host server.example.net are forwarded in RFC 3164
    # format (using the template defined above).
    #
    kern.* /var/adm/kernel
    kern.crit @server.example.net;RFC3164fmt
    kern.crit /dev/console
    kern.info;kern.!err /var/adm/kernel-info

The first rule direct any message that has the kernel facility to the file /var/adm/kernel.

The second statement directs all kernel messages of the priority crit and higher to the remote host server.example.net. This is useful, because if the host crashes and the disks get irreparable errors you might not be able to read the stored messages. If they’re on a remote host, too, you still can try to find out the reason for the crash.

The third rule directs these messages to the actual console, so the person who works on the machine will get them, too.

The fourth line tells rsyslogd to save all kernel messages that come with priorities from info up to warning in the file /var/adm/kernel-info. Everything from err and higher is excluded.

    # The tcp wrapper loggs with mail.info, we display
    # all the connections on tty12
    #
    mail.=info /dev/tty12

This directs all messages that uses mail.info (in source LOG_MAIL | LOG_INFO) to /dev/tty12, the 12th console. For example the tcpwrapper tcpd(8) uses this as it’s default.

    # Store all mail concerning stuff in a file
    #
    mail.\*;mail.!=info /var/adm/mail

This pattern matches all messages that come with the mail facility, except for the info priority. These will be stored in the file /var/adm/mail.

    # Log all mail.info and news.info messages to info
    #
    mail,news.=info /var/adm/info

This will extract all messages that come either with mail.info or with news.info and store them in the file /var/adm/info.

    # Log info and notice messages to messages file
    #
    *.=info;*.=notice;\
    mail.none /var/log/messages

This lets rsyslogd log all messages that come with either the info or the notice facility into the file /var/log/messages, except for all messages that use the mail facility.

    # Log info messages to messages file
    #
    *.=info;\
    mail,news.none /var/log/messages

This statement causes rsyslogd to log all messages that come with the info priority to the file /var/log/messages. But any message coming either with the mail or the news facility will not be stored.

    # Emergency messages will be displayed to all users
    #
    *.=emerg :omusrmsg:*

This rule tells rsyslogd to write all emergency messages to all currently logged in users.

    # Messages of the priority alert will be directed
    # to the operator
    #
    *.alert root,rgerhards

This rule directs all messages with a priority of alert or higher to the terminals of the operator, i.e. of the users “root’’ and “rgerhards’’ if they’re logged in.

    *.* @server.example.net

This rule would redirect all messages to a remote host called server.example.net. This is useful especially in a cluster of machines where all syslog messages will be stored on only one machine.

In the format shown above, UDP is used for transmitting the message. The destination port is set to the default auf 514. Rsyslog is also capable of using much more secure and reliable TCP sessions for message forwarding. Also, the destination port can be specified. To select TCP, simply add one additional @ in front of the host name (that is, @host is UDP, @@host is TCP). For example:

    *.* @@server.example.net

To specify the destination port on the remote machine, use a colon followed by the port number after the machine name. The following forwards to port 1514 on server.example.net:

    *.* @@server.example.net:1514

This syntax works both with TCP and UDP based syslog. However, you will probably primarily need it for TCP, as there is no well-accepted port for this transport (it is non-standard). For UDP, you can usually stick with the default auf 514, but might want to modify it for security reasons. If you would like to do that, it’s quite easy:

    *.* @server.example.net:1514
    *.* >dbhost,dbname,dbuser,dbpassword;dbtemplate

This rule writes all message to the database “dbname” hosted on “dbhost”. The login is done with user “dbuser” and password “dbpassword”. The actual table that is updated is specified within the template (which contains the insert statement). The template is called “dbtemplate” in this case.

    :msg,contains,"error" @server.example.net

This rule forwards all messages that contain the word “error” in the msg part to the server “errorServer”. Forwarding is via UDP. Please note the colon in front

See also

Help with configuring/using `Rsyslog`:

- Mailing list - best route for general questions

- GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with `Rsyslog`

See also

Contributing to `Rsyslog`:

- Source project: rsyslog project README.

- Documentation: rsyslog-doc project README

Copyright 2008-2023 Rainer Gerhards (Großrinderfeld), and Others.