- Syslog new log notifier and parser.
[-c epylog.conf] [-d LOGLEVEL] [--last PERIOD]
[--store-offsets] [--quiet] [--cron]
Epylog is a new log notifier and parser which runs periodically out of cron,
looks at your logs, processes the entries in order to present them in a more
comprehensive format, and then provides you with the output. It is written
specifically with large network clusters in mind where a lot of machines
(around 50 and upwards) log to the same loghost using syslog or syslog-ng.
Alternatively, Epylog can be invoked from the command line and provide a log
report based on a certain provided time period. In this case it relies on
syslog timestamps to find the offsets, as opposed to the end-of-log offsets
stored during the last run, though this behavior is not as reliable and is
easily thwarted by skewed clocks.
- -c config.file
- Provide an alternative config file to Epylog. By default,
it will look in /etc/epylog/epylog.conf.
- -d LOGLEVEL
- Logging level. The default is 1. 0 will produce no output
except for critical errors (useful for cron runs). 2 and above are
debugging levels. 5 is the most verbose.
- --last PERIOD
- Will make a report on events that occurred in the last
PERIOD. PERIOD can be either "hour", "day",
"week", "month", or more granular: "1h",
"2h", "3d", "2w", etc. When --last is
specified, epylog will ignore the saved offsets and locate the entries by
timestamps. CAUTION: this process is not to be trusted, since the
timestamps are not checked for any validity when arriving to the loghost.
One reporting machine with a skewed clock may confuse Epylog enough to
miss a lot of valid entries.
- When specified, will store the offset of the last log entry
processed in offsets.xml. During the cron runs epylog relies on the offset
information to find out what new entries to process. This is more
trustworthy than relying on timestamps. The default behavior is not to
store the offsets, as this allows to run epylog both from cron and
manually without the two interfering with each-other. The location of
offset.xml is specified in epylog.conf. See epylog.conf(5) for more
- In every way identical to -d 0.
- This is essentially --quiet --store-offsets, plus a
lockfile will be created and consulted, preventing more than one instance
of epylog from running. You can still run epylog manually -- the lockfile
is only checked when running in --cron mode.
The core of epylog is written in python. It
handles things like timestamp lookups, unwrapping of "last message
repeated" lines, handling of rotated files, preparing and publishing the
The modules are pluggable and can be either "internal", written in
python, or external. External modules can be written in any language, but at a
price of some convenience. For more info see epylog-modules(5)
Depending on the size of your logs, you might
want to initialize your offsets before letting epylog run from cron. When the
offsets.xml file is missing, epylog will by default process the entire log,
and depending on your configuration, that can be a lot of entries. A good way
to init epylog is to run:
epylog --last day --store-offsets
The useful way to run from a command line is with --last. E.g.:
epylog --last day
epylog --last 2w
When running from cron, you want to store the offsets and not rely on
timestamps. There is a mode that allows you to do this:
Konstantin Ryabitsev <email@example.com>