Internal IP addresses are either manually configured and included in the hosts file or assigned by Server Management via DHCP and referenced via the CMIC configuration.
External interfaces and corporate DNS must use the same hostnames that Hadoop uses on the internal BYNET network.
If an application or user requests data from the namenode service, the service returns a location based on the hostname Hadoop is using. When external clients access Hadoop, the Hadoop hostnames must be included in the corporate DNS or resolve the Hadoop hostname to its external interface via the local /etc/hosts.
The diagram illustrates the Hadoop cluster configured for external client access. The /etc/hosts file in each Hadoop node has hostnames associated with the internal BYNET network, while the external client’s /etc/hosts file is associated with the Hadoop node’s public IP.