IP groups overview
IBM® Cloud Pak System Software for Power® manages IP groups, or collections of IP addresses.
An IP group is a list or range of IP addresses that you can select to then use with specific virtual machines. For example, you might split 100 IP addresses into four blocks of 25 IP addresses to be used by four departments in your enterprise. Though these IP addresses are all on the same real subnet in this example, creating the IP groups enables you to isolate them. You can then ensure that they are only used by Cloud Pak System Software for a particular purpose. In addition, Cloud Pak System Software creates one IP group per location to hold all reserved virtual IP addresses for public access to the virtual machines. Since reserved Virtual IP addresses incur charges, this view provides a convenient location to see how many Virtual IP addresses are reserved.
Cloud Pak System Software accesses IP addresses through IP groups. Cloud Pak System Software uses all available IP addresses from the IP group. During the deployment process, virtual machines continue to be assigned IP addresses until the IP group runs out of IP addresses.
When you create an IP group, you specify settings such as gateway, subnet and DNS for use in connecting to the enterprise network. You then define the VLAN for the network traffic and a pool of IP addresses within the subnet. IP groups enable you to partition a subnet. Therefore, blocks of IP addresses from the subnet can be assigned to a virtual machine, department, or other entity. You can also partition the subnet into smaller groupings. You can create IP groups with duplicate subnet information. You can enter IP addresses by specifying a range in the console or the command-line interface.
If you do not enter any IP addresses, you cannot deploy virtual machines to hypervisors using that IP group. Messages alert you to possible errors.
The IP group must have available addresses for the maximum number of virtual machines that you want accessible in the cloud. To enhance performance, a minimum of 10 available IP addresses is optimal, however for any significant cloud deployments, substantially more available IP addresses are needed. To determine how many IP addresses you need, you can count the number of virtual image parts. Each virtual image part is equal to one unique IP address.