Managing HP Serviceguard for Linux, Tenth Edition, September 2012

IMPORTANT: See “About Hostname Address Families: IPv4-Only, IPv6-Only, and Mixed
Mode” (page 100) for a full discussion, including important restrictions for IPv6–only and
mixed modes.
If you use the -a option, Serviceguard will ignore the value of the
HOSTNAME_ADDRESS_FAMILY parameter in the existing cluster configuration, if any,
and attempt to resolve the cluster and Quorum Server hostnames as specified by the -a
option:
• If you specify -a ipv4, each of the hostnames must resolve to at least one IPv4
address; otherwise the command will fail.
• Similarly, if you specify -a ipv6, each of the hostnames must resolve to at least
one IPv6 address; otherwise the command will fail.
• If you specify -a any, Serviceguard will attempt to resolve each hostname to an
IPv4 address, then, if that fails, to an IPv6 address.
If you do not use the -a option:
• If a cluster is already configured, Serviceguard will use the value configured for
HOSTNAME_ADDRESS_FAMILY, which defaults to IPv4.
• If no cluster configured, and Serviceguard finds at least one IPv4 address that
corresponds to the local node's hostname (that is, the node on which you are running
cmquerycl), Serviceguard will attempt to resolve all hostnames to IPv4 addresses.
If no IPv4 address is found for a given hostname, Serviceguard will look for an IPv6
address. (This is the same behavior as if you had specified -a any.)
Specifying the Address Family for the Heartbeat
To tell Serviceguard to use only IPv4, or only IPv6, addresses for the heartbeat, use the
-h option. For example, to use only IPv6 addresses:
cmquerycl -v -h ipv6 -C $SGCONF/clust1.conf -n ftsys9 -n ftsys10
• -h ipv4 tells Serviceguard to discover and configure only IPv4 subnets. If it does
not find any eligible subnets, the command will fail.
• -h ipv6 tells Serviceguard to discover and configure only IPv6 subnets. If it does
not find any eligible subnets, the command will fail.
• If you don't use the -h option, Serviceguard will choose the best available
configuration to meet minimum requirements, preferring an IPv4 LAN over IPv6
where both are available. The resulting configuration could be IPv4 only, IPv6 only,
or a mix of both. You can override Serviceguard's default choices by means of the
HEARTBEAT_IP parameter, discussed under “Cluster Configuration Parameters ”
(page 103); that discussion also spells out the heartbeat requirements.
• The-h and -c options are mutually exclusive.
Configuring the Cluster 181