Managing HP Serviceguard for Linux, Tenth Edition, September 2012

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 101) and “Rules and Restrictions
for Mixed Mode” (page 103), respectively, and the latest version of the Serviceguard
release notes.
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 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
IMPORTANT: Serviceguard does not support aliases for IPv6 addresses.
For information about configuring an IPv6–only cluster, or a cluster that uses a combination
of IPv6 and IPv4 addresses for the nodes' hostnames, see “About Hostname Address
Families: IPv4-Only, IPv6-Only, and Mixed Mode” (page 100).
160 Building an HA Cluster Configuration