You do not need to configure a private network for a single-node cluster. The scinstall utility automatically assigns the default private-network address and netmask, even though a private network is not used by the cluster.
Sun Cluster software uses the private network for internal communication among nodes and among non-global zones that are managed by Sun Cluster software. A Sun Cluster configuration requires at least two connections to the cluster interconnect on the private network. When you configure Sun Cluster software on the first node of the cluster, you specify the private-network address and netmask in one of the following ways:
Accept the default private-network address (172.16.0.0) and netmask (255.255.248.0). This IP address range supports a combined maximum of 64 nodes and non-global zones and a maximum of 10 private networks.
The maximum number of nodes that an IP address range can support does not reflect the maximum number of nodes that the hardware configuration can support.
Specify a different allowable private-network address and accept the default netmask.
Accept the default private-network address and specify a different netmask.
Specify both a different private-network address and a different netmask.
If you choose to specify a different netmask, the scinstall utility prompts you for the number of nodes and the number of private networks that you want the IP address range to support. The number of nodes that you specify should also include the expected number of non-global zones that will use the private network.
The utility calculates the netmask for the minimum IP address range that will support the number of nodes and private networks that you specified. The calculated netmask might support more than the supplied number of nodes, including non-global zones, and private networks. The scinstall utility also calculates a second netmask that would be the minimum to support twice the number of nodes and private networks. This second netmask would enable the cluster to accommodate future growth without the need to reconfigure the IP address range.
The utility then asks you what netmask to choose. You can specify either of the calculated netmasks or provide a different one. The netmask that you specify must minimally support the number of nodes and private networks that you specified to the utility.
To change the private-network address and netmask after the cluster is established, see How to Change the Private Network Address or Address Range of an Existing Cluster in Sun Cluster System Administration Guide for Solaris OS. You must bring down the cluster to make these changes.
Changing the cluster private IP address range might be necessary to support the addition of nodes, non-global zones, or private networks.
If you specify a private-network address other than the default, the address must meet the following requirements:
Address and netmask sizes - The private network address cannot be smaller than the netmask. For example, you can use a private network address of 172.16.10.0 with a netmask of 255.255.255.0. But you cannot use a private network address of 172.16.10.0 with a netmask of 255.255.0.0.
Acceptable addresses - The address must be included in the block of addresses that RFC 1918 reserves for use in private networks. You can contact the InterNIC to obtain copies of RFCs or view RFCs online at http://www.rfcs.org.
Use in multiple clusters - You can use the same private network address in more than one cluster. Private IP network addresses are not accessible from outside the cluster.
IPv6 - Sun Cluster software does not support IPv6 addresses for the private interconnect. The system does configure IPv6 addresses on the private network adapters to support scalable services that use IPv6 addresses. But internode communication on the private network does not use these IPv6 addresses.