• Support Logging setup

    Logstash Custom Parsing

    Logstash Custom Parsing

    You can setup Logstash to do custom parsing of your logs and then send the output to Loggly. Logstash is able to parse logs using grok filters. This can be useful if your log format is not one of our automatically parsed formats. Parsing allows you to use advance features like statistical analysis on value fields, faceted search, filters and more.

    1. Setup Logstash

    If you haven’t already, configure Logstash to output to Loggly.

    2. Configure A Grok Filter

    Grok is library of expressions that make it easy to extract data from your logs. You can select from hundreds of available grok patterns.

    In this example, we have taken an example of the kern.log file and created a custom log format for the kernel logs and added in the Grok Filter.

    Sample log line from kern.log file

    Sep 24 08:12:51 ubuntu kernel: [ 0.000000] Calgary: Unable to locate Rio Grande table in EBDA - bailing!

    Custom format used

    %{CISCOTIMESTAMP:timestamp} %{HOST:host} %{WORD:program}%{NOTSPACE} %{NOTSPACE}%{NUMBER:duration}%{NOTSPACE} %{GREEDYDATA:kernel_logs}

    Paste this into your logstash configuration file, replacing your own customer token.

          path => "/var/log/kern.log"
          start_position => beginning
          add_field => {"source" => "logstash"}
          match => {"message" => "%{CISCOTIMESTAMP:timestamp} %{HOST:host} %{WORD:program}%{NOTSPACE} %{NOTSPACE}%{NUMBER:duration}%{NOTSPACE} %{GREEDYDATA:kernel_logs}"}
          host => "logs-01.loggly.com"
          key => "TOKEN"
          proto => "http"


    3. Verify Events

    See the output below for the above mentioned custom format.

    Logstash Custom Parsing Example


    Advanced Logstash Custom Parsing Options

    Troubleshooting Logstash Custom Parser

    If you don’t see any data show up in the verification step, then check for these common problems.

    Check logstash configuration:

    Still Not Working?

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