In HopsFS DataNodes should register with all the available NameNodes in the cluster. Part of the greater effort of using a service discovery system - Consul - is to abstract all the IPs or static hostnames from the configuration files and replace them with more generic domain names.
DNs construct a list of available NNs by squashing the configuration properties dfs.namenodes.rpc.addresses and dfs.namenode.rpc-address. With service discovery in place DNs should get all the NNs IPs by quering for a generic domain such as namenode.service.consul
This JIRA is related with https://logicalclocks.atlassian.net/browse/HOPSWORKS-1405