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Dire need for centralized logging

We have HA in some components of the application and any request can go to any of the tomcats in Data centre. The problem is that lately I have been asked to chase a lot of customer issues and its a PITA to grep logs across all machines and make a time line and then figure out what's going on.  What we need is to log to some central server in addition to local box and then all these debugging things can be grepped here.  We are finally picking logstash for this purpose because you can do lucene like search queries on customer name (we append customer name in thread). Also we generate a unique requestId for all requests coming to data centre which gets passed through many components. We would put all those logs in logstash so we can see how the request flows through all components. We would keep 1-2 months of logs else it would be tons of logs.

We are finally picking http://syslog4j.org/docs/javadoc/org/productivity/java/syslog4j/impl/log4j/Syslog4jAppender.html for this but running into some issues with appender. Will write a blog once I solve it.

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