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Veritas Access Installation Guide

Last Published: 2018-07-27

Product(s): Access (7.3.1)

Platform: Linux

About calculating IP address requirements

This section provides an example of how to calculate IP addresses for a two-node cluster. In this example, all the nodes in the cluster have the same hardware configuration. Therefore, the number of network interface cards (NICs) is the same for all the nodes in the cluster.

Two private NICs and two public NICs should be connected to respective networks.
One public IP address should be assigned to one of the public interface for installation over ssh. None of the private interfaces should have the IP address in the same network segment.
The public IP address must be made permanent by writing it to the network configuration file /etc/sysconfig/network-scripts/ifcfg-ethX.

Table: Example calculation of required IPs for a standard configuration

Number of IPs	Item
2	Number of nodes in the cluster
4	Number of interfaces on each node
2	Number of the private interfaces that are required for each node

After two private interfaces on each node are selected, all remaining interfaces act as public interfaces.

To calculate the number of public interfaces per node

The total number of interfaces on the node, minus the number of private interfaces that are required on a node, is equal to the remaining number of public interfaces on the node.
```
Total number of interfaces (4)
- Number of private interfaces (2)
= Number of public interfaces 

4 - 2 = 2
```

To calculate the physical and the virtual IP addresses for the cluster

The total number of physical IP addresses that are required for the cluster installation is equal to the number of nodes in the cluster multiplied by the number of public interfaces on each node:
```
Total number of nodes (2)
x Number of public interfaces per node (2)
= Total number of physical IP addresses

= 2 x 2 = 4
```
The number of nodes in the cluster multiplied by the number of public interfaces on each node is equal to the total number of virtual IP addresses that are required for the cluster installation:
```
Total number of nodes (2)
x Number of public interfaces per node (2)
= Total number of virtual IP addresses

= 2 x 2 = 4
```
The number of IP addresses required for the Veritas Access Operations Manager is equal to one (1).

To calculate the total number of public IP addresses for the cluster

The number of physical IP addresses for the cluster, plus the number of virtual IP addresses for the cluster, plus the number of IP addresses for the Operations Manager is equal to the total number of public IP addresses that are required for the cluster.
```
Total number of physical IP addresses/cluster (4)
+ Total number of virtual IP addresses/cluster (4)
+ Number of IP addresses for the Management Console (1)
= Total number of public IP addresses required for the cluster

= 4 + 4 + 1 = 9
```

To request and specify IP addresses

Request the public IP addresses that you need from your Network Administrator.
For example, if the Network Administrator provides you with IP addresses 10.209.105.120 through 10.209.105.128, you can allocate the resources in the following manner:
```
Start of Physical IP address: 10.209.105.120
Start of Virtual IP address: 10.209.105.124
Management Console IP:"10.209.105.128"
```
This entry gives you four physical IP addresses (10.209.105.120 to 10.209.105.123), four virtual IP addresses (10.209.105.124 to 10.209.105.127), and one IP address for the Operations Manager (10.209.105.128).
10.209.105.120 and 10.209.105.121 are assigned to pubeth0 and pubeth1 as physical IP addresses on the first node.
10.209.105.122 and 10.209.105.123 are assigned to pubeth0 and pubeth1 as physical IP addresses on the second node.
10.209.105.124 to 10.209.105.127 are assigned to pubeth0 and pubeth1 as virtual IP addresses on the two nodes.