In this recipe, we look at how we can fetch the configured parameters in the Hadoop cluster, without going through the files.
The parameters are either default values, defined by files such as
yarn-default.xml, and so on, or defined explicitly in the configuration files such as
mapred-site.xml, and a few others. The default files are part of the packaged jars with the distribution, and any changes we make overrides them.
To step through the recipe, the user needs at least one node in the cluster and needs to make sure that the Hadoop environment variables are in place. It is not necessary to start any of the daemons in the cluster. ...