Managing HP Serviceguard for Linux Ninth Edition, April 2009
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 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 more
information about configuring a combination of IPv6 and IPv4 addresses, see the
discussion of the HOSTNAME_ADDRESS_FAMILY parameter under “Cluster
Configuration Parameters ” (page 100).
Safeguarding against Loss of Name Resolution Services
When you employ any user-level Serviceguard command (including cmviewcl), the
command uses the name service you have configured (such as DNS) to obtain the
addresses of all the cluster nodes. If the name service is not available, the command
could hang or return an unexpected networking error message.
Preparing Your Systems 151