Linux Logging Configuration
Internal
rsyslogd Configuration
The main rsyslogd configuration file is /etc/rsyslog.conf.
The configuration file contains global directives, rules and modules. A rule consists of filter and action. The filters can be facility/priority-based, property-based and expression-based.
For more details on rsyslogd configuration see
rsyslogd Log Rotation Configuration
rsyslogd-managed log files can be automatically rotated. The logrotate package contains a cron task that rotates log files based on the configuration found in /etc/logrotate.conf and /etc/logrotate.d/. The cron job runs daily. The essential configuration is similar to:
# rotate log files weekly
weekly
# keep 4 weeks worth of backlogs
rotate 4
# create new (empty) log files after rotating old ones
create
# use date as a suffix of the rotated file
dateext
# uncomment this if you want your log files compressed
#compress
# RPM packages drop log rotation information into this directory
include /etc/logrotate.d
# no packages own wtmp and btmp -- we'll rotate them here
/var/log/wtmp {
monthly
create 0664 root utmp
minsize 1M
rotate 1
}
/var/log/btmp {
missingok
monthly
create 0600 root utmp
rotate 1
}
# system-specific logs may be also be configured here.
All entries in /etc/logrotate.conf apply to every log file managed by rsyslogd, including to those whose configuration is specified in individual entries or in /etc/logrotate.d. Individua log file handing can be specified in /etc/logrotate.conf, as it is the case for /var/log/wtmp and /var/log/btmp in the above example, or in separated files placed in /etc/logrotate.d. Comments must be placed on lines that begin with '#'. Details on the configuration file syntax can be obtained with:
man logrotate
Configuration directives:
daily | weekly | monthly | yearly
Specifies the rotation periodicity.
rotate <integer>
Specifies the number of rotation the log file undergoes before it is removed or mailed. If 0 is specified, old files are removed immediately.
Log Rotation Configuration File Syntax Verfiication
logrotate -d -f /etc/logrotate.conf
journald Configuration
More details about journald.