Managing HP Serviceguard A.11.20.00 for Linux, June 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 78) and “Rules and Restrictions for Mixed
Mode” (page 79), 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
Keep the following rules in mind when creating entries in a Serviceguard node's/etc/hosts:
1. 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 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 80).
NOTE: Since Serviceguard recognizes only the hostname, gryf.uksr.hp.com and
gryf.cup.hp.com cannot be nodes in the same cluster, Serviceguard identifies them as the
same host gryf.
2. All primary IP addresses configured.
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 77).
124 Building an HA Cluster Configuration