4. Collect Information

To deploy your Hadoop installation, you need to collect the following information:

The fully qualified domain name (FQDN) for each host in your system, and which components you want to set up on which host. The Ambari install wizard does not support using IP addresses. You can use hostname -f to check for the FQDN if you do not know it.
Note
While it is possible to deploy all of Hadoop on a single host, this is appropriate only for initial evaluation. In general you should use at least three hosts: one master host and two slaves.
The base directories you want to use as mount points for storing:
- NameNode data
- DataNodes data
- Secondary NameNode data
- Oozie data
- MapReduce data (Hadoop version 1.x)
- YARN data (Hadoop version 2.x)
- ZooKeeper data, if you install ZooKeeper
- Various log, pid, and db files, depending on your install type

	Note
While it is possible to deploy all of Hadoop on a single host, this is appropriate only for initial evaluation. In general you should use at least three hosts: one master host and two slaves.