Determine the required IP pool size for the new deployment, you can choose to define new IP address ranges or reuse your existing IP address ranges.

The VLAN tags in the existing deployment are reused in the new deployment. Ensure that the VLAN tags are properly retained in the new configuration.

In a Red Hat OpenStack Services on OpenShift (RHOSO) deployment, each service that is deployed on the Red Hat OpenShift Container Platform (RHOCP) worker nodes requires an IP address from the IP Address Management (IPAM) pool. In a Red Hat OpenStack Platform (RHOSP) deployment, all services that are hosted on a Controller node share the same IP address.

The RHOSO control plane has different requirements for the number of IP addresses that are made available for services. Depending on the size of the IP ranges that are used in the existing RHOSO deployment, you might reuse these ranges for the RHOSO control plane.

The total number of IP addresses that are required for the new control plane services in each isolated network is calculated as the sum of the following:

• The number of RHOCP worker nodes. Each worker node requires 1 IP address in the NodeNetworkConfigurationPolicy custom resource (CR).
• The number of IP addresses required for the data plane nodes. Each node requires an IP address from the NetConfig CRs.
• The number of IP addresses required for control plane services. Each service requires an IP address from the NetworkAttachmentDefinition CRs. This number depends on the number of replicas for each service.
• The number of IP addresses required for load balancer IP addresses. Each service requires a Virtual IP address from the IPAddressPool CRs.

For example, a simple single worker node RHOCP deployment with Red Hat OpenShift Local has the following IP ranges defined for the internalapi network:

• 1 IP address for the single worker node
• 1 IP address for the data plane node
• NetworkAttachmentDefinition CRs for control plane services: X.X.X.30-X.X.X.70 (41 addresses)
• IPAllocationPool CRs for load balancer IPs: X.X.X.80-X.X.X.90 (11 addresses)

This example shows a total of 54 IP addresses allocated to the internalapi allocation pools.

The requirements might differ depending on the list of RHOSP services to be deployed, their replica numbers, and the number of RHOCP worker nodes and data plane nodes.

Additional IP addresses might be required in future RHOSP releases, so you must plan for some extra capacity for each of the allocation pools that are used in the new environment.