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Understanding the Grid parameters

You can tweak the behavior of the Hub/Node using the configuration parameters and do stuff such as :

Have the Hub (or) the Node listen on a different port other than the default ones.
Explicitly specify the host for either the Hub (or) the Node.
Use a JSON configuration file to control the Hub (or) the Node behavior.
Control which of the optional servlets should be wired in at the Hub or at the Node.
Enable debug level logs and have them redirected to a file for later analysis.

and much more…