disco-slct is a mapreduce implementation of SLCT. According to the SLCT website:
SLCT is a tool that was designed to find clusters in logfile(s), so that each cluster corresponds to a certain line pattern that occurs frequently enough.
Examples of the clusters that SLCT, and thus disco-slct, is able to detect:
Dec 18 * myhost.mydomain sshd[*]: log: Connection from * port * Dec 18 * myhost.mydomain sshd[*]: log: Password authentication for * accepted.
With the help of SLCT, one can quickly build a model of logfile(s), and also identify rare lines that do not fit the model (and are possibly anomalous). disco-slct uses Disco for it's backend.
Optionally you'd want to push your logfiles to DDFS if you have a lot of them. Information on how to do this can be found in the Disco tutorial.
Next, you choose a threshold, which is the mininum support value for each log pattern. This is the number of lines that each line outputted by disco-slct will match in your log files.
$ python ./dslct.py -s <THRESHOLD> <DISCO_URL_TO_YOUR_LOGFILE>
You can always issue
$ python ./dslct.py --help
to see exact parameters to disco-slct.