Managing Serviceguard Sixteenth Edition, March 2009

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 198) 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 example, consider a two node cluster (gryf and sly) with two private subnets
and a public subnet. These nodes will be granting access by a non-cluster node (bit)
which does not share the private subnets. The /etc/hosts file on both cluster nodes
should contain:
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
15.145.162.150 bit.uksr.hp.com bit
NOTE: Serviceguard recognizes only the hostname (the first element) in a fully
qualified domain name (a name with four elements separated by periods, like those
in the example above). This means, for example, that 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.
If applications require the use of hostname aliases, the Serviceguard hostname must
be one of the aliases in all the entries for that host. For example, if the two-node cluster
in the previous example were configured to use the alias hostnames alias-node1
and alias-node2, then the entries in /etc/hosts should look something like this:
15.145.162.131 gryf.uksr.hp.com gryf1 alias-node1
10.8.0.131 gryf2.uksr.hp.com gryf2 alias-node1
10.8.1.131 gryf3.uksr.hp.com gryf3 alias-node1
15.145.162.132 sly.uksr.hp.com sly1 alias-node2
10.8.0.132 sly2.uksr.hp.com sly2 alias-node2
10.8.1.132 sly3.uksr.hp.com sly3 alias-node2
Preparing Your Systems 197