Hortonworks and Cloudera are two main distributors of Hadoop. These distributors have their own style of installation. The installation is done as a package installation through
yum (CentOS) or
apt-get (Ubuntu). The directory structure is different for configuration files, log files,
.pid files, and so on.
Both these distributors have developed tools to provision, manage, and monitor the Hadoop clusters through a web UI. Cloudera Manager from Cloudera and Apache Ambari are being used by a majority of the companies. Ambari is an open source project that lacks features such as rolling upgrades, managements of third-party libraries, and so on. Cloudera Manager is a mature product and is available in both Express and Enterprise versions.
To read more about Cloudera Manager and Ambari, you can refer to the official website at http://www.cloudera.com/content/cloudera/en/products-and-services/cloudera-enterprise/cloudera-manager.html.