NDB Cluster Installation Figure 23.4 NDB Cluster Multi-Computer Setup Network addressing.  In the interest of simplicity (and reliability), this  How-To  uses only numeric IP addresses. However, if DNS resolution is available on your network, it is possible to use host names in lieu of IP addresses in configuring Cluster. Alternatively, you can use the  hosts  file (typically  /etc/ hosts  for Linux and other Unix-like operating systems,  C:\WINDOWS\system32\drivers\etc\hosts on Windows, or your operating system’s equivalent) for providing a means to do host lookup if such is available. Prior to NDB 8.0.22, all network addresses used for connections to or from data and management nodes must use or be resolvable using IPv4. This includes addresses used by SQL nodes to contact the other nodes. Beginning with NDB 8.0.22, NDB Cluster supports IPv6 for connections between any and all cluster nodes. Potential hosts file issues.   A common problem when trying to use host names for Cluster nodes arises because of the way in which some operating systems (including some Linux distributions) set up the system’s own host name in the  /etc/hosts  during installation. Consider two machines with the host names  ndb1  and  ndb2 , both in the  cluster  network domain. Red Hat Linux (including some derivatives such as CentOS and Fedora) places the following entries in these machines’  /etc/hosts  files: SUSE Linux (including OpenSUSE) places these entries in the machines’  /etc/hosts  files: In both instances,  ndb1  routes  ndb1.cluster  to a loopback IP address, but gets a public IP address from DNS for  ndb2.cluster , while  ndb2  routes  ndb2.cluster  to a loopback address and obtains a # ndb1 /etc/hosts: 127.0.0.1 ndb1.cluster ndb1 localhost.localdomain localhost # ndb2 /etc/hosts: 127.0.0.1 ndb2.cluster ndb2 localhost.localdomain localhost # ndb1 /etc/hosts: 127.0.0.1 localhost 127.0.0.2 ndb1.cluster ndb1 # ndb2 /etc/hosts: 127.0.0.1 localhost 127.0.0.2 ndb2.cluster ndb2 3977