Logging does not work

I upgraded my elasticsearch node from 1.5.1 to 1.7.3.
Logging.yml file has not changed.
But i dont see any new records in elasticsearch.log since upgrade.

When starting elasticsearch daemon, this message appears:

log4j:WARN No appenders could be found for logger (common).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

I also copied elasticsearch.yml and logging.yml in $ES_HOME/config/ folder.
This did not help.

How can i see my log messages?

Its really impossible to tell what is up without looking at your system. It works for most folks.

I'd debug this by checking the command line parameters that are passed to java when running elasticsearch.

I checked /etc/init.d/elasticsearch script and found this java option

Somehow LOG_DIR variable was empty. I set it to /var/log/elasticsearch/ and it solved the problem.