The Ambari cluster installer automatically creates user and group accounts for you. Ambari preserves any existing user and group accounts, and uses these accounts when configuring Hadoop services. User and group creation applies to user/group accounts on the local operating system and to LDAP/AD accounts.
To set up custom accounts before running the Ambari installer, see Service Users and Groups (for the 1.x stack) or Service Users and Groups (for the 2.x stack) for more information about customizing service users and groups.
