Managing HP Serviceguard A.12.00.00 for Linux, June 2014

4.8.3.2.2 Recommendations for IPv6-Only Mode
IMPORTANT: Check the latest Serviceguard for Linux release notes for the latest instructions and
recommendations.
• If you decide to migrate the cluster to IPv6-only mode, you should plan to do so while the
cluster is down.
4.8.3.3 What Is Mixed Mode?
If you configure mixed mode (HOSTNAME_ADDRESS_FAMILY set to ANY, or cmquerycl -a
any) then the addresses used by the cluster, including the heartbeat, and Quorum Server addresses
if any, can be IPv4 or IPv6 addresses. Serviceguard will first try to resolve a node's hostname to
an IPv4 address, then, if that fails, will try IPv6.
4.8.3.3.1 Rules and Restrictions for Mixed Mode
IMPORTANT: See the latest version of the Serviceguard release notes for the most current
information on these and other restrictions.
• Red Hat 5 and Red Hat 6 clusters are not supported.
NOTE: This also applies if HOSTNAME_ADDRESS_FAMILY is set to IPv6; Red Hat 5 supports
only IPv4-only clusters.
• The hostname resolution file on each node (for example, /etc/hosts) must contain entries
for all the IPv4 and IPv6 addresses used throughout the cluster, including all STATIONARY_IP
and HEARTBEAT_IP addresses as well any private addresses. There must be at least one
IPv4 address in this file (in the case of /etc/hosts, the IPv4 loopback address cannot be
removed). In addition, the file must contain the following entry:
::1 localhost ipv6-localhost ipv6-loopback
For more information and recommendations about hostname resolution, see “Configuring
Name Resolution” (page 145).
• You must use $SGCONF/cmclnodelist, not ~/.rhosts or /etc/hosts.equiv, to
provide root access to an unconfigured node.
See “Allowing Root Access to an Unconfigured Node” (page 144) for more information.
• Hostname aliases are not supported for IPv6 addresses, because of operating system limitations.
NOTE: This applies to all IPv6 addresses, whether HOSTNAME_ADDRESS_FAMILY is set to
IPV6 or ANY.
• Cross-subnet configurations are not supported.
This also applies if HOSTNAME_ADDRESS_FAMILY is set to IPV6. See “Cross-Subnet
Configurations” (page 27) for more information about such configurations.
• Virtual machines are not supported.
You cannot have a virtual machine that is either a node or a package if
HOSTNAME_ADDRESS_FAMILY is set to ANY or IPV6.
4.8.4 Cluster Configuration Parameters
You need to define a set of cluster parameters. These are stored in the binary cluster configuration
file, which is distributed to each node in the cluster. You configure these parameters by editing the
4.8 Cluster Configuration Planning 89