HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

Configuring Name Resolution
Serviceguard uses the name resolution services built into HP-UX.
NOTE: If you plan to use cmpreparecl (1m) (or cmpdeploycl (1m), which calls
cmpreparecl), the /etc/hosts and /etc/nsswitch.conf configuration described in this
subsection will be done automatically, but you should still read the entire subsection and make
sure you understand the issues.
In particular, you still need to make sure that aliases are properly represented in /etc/hosts,
as described below.
Serviceguard nodes can communicate over any of the cluster’s shared networks, so the network
resolution service you are using (such as DNS, NIS, or LDAP) must be able to resolve each of their
primary addresses on each of those networks to the primary hostname of the node in question.
In addition, HP recommends that you define name resolution in each node’s /etc/hosts file,
rather than rely solely on a service such as DNS. Configure the name service switch to consult the
/etc/hosts file before other services. See “Safeguarding against Loss of Name Resolution
Services” (page 169) for instructions.
NOTE: If you are using private IP addresses for communication within the cluster, and these
addresses are not known to DNS (or the name resolution service you use) these addresses must
be listed in /etc/hosts.
For requirements and restrictions that apply to IPv6–only clusters and mixed-mode clusters, see
“Rules and Restrictions for IPv6-Only Mode” (page 107) and “Rules and Restrictions for Mixed
Mode” (page 109), respectively, and the latest version of the Serviceguard release notes.
Keep the following rules in mind when creating entries in a Serviceguard node's/etc/hosts:
• NODE_NAME in the cluster configuration file must be identical to the hostname which is the
first element of a fully qualified domain name (a name with four elements separated by periods).
This hostname is what is returned by the HP-UX hostname(1) command.
For example, the NODE_NAME should be gryf rather than gryf.uksr.hp.com. For more
information, see the NODE_NAME entry under “Cluster Configuration Parameters ” (page 109).
NOTE: Since Serviceguard recognizes only the hostname, gryf.uksr.hp.com and
gryf.cup.hp.com cannot be nodes in the same cluster, as Serviceguard would see them
as the same host gryf.
• All primary IP addresses configured on the system must map to an entry in which the
NODE_NAME is either:
◦ the official hostname, as defined by hosts (4), for example
15.145.162.131 gryf
or :
◦ any of the aliases. Examples:
15.145.162.131 gryf.uksr.hp.com gryf
10.8.0.131 gryf.uksr.hp.com gryf
10.8.1.131 gryf.uksr.hp.com gryf
15.145.162.132 sly.uksr.hp.com sly
10.8.0.132 sly.uksr.hp.com sly
10.8.1.132 sly.uksr.hp.com sly
...
168 Building an HA Cluster Configuration