Merge pull request #76834 from snarayan-redhat/OSDOCS-10734_ipv4pool

OSDOCS#10734: AWS Public IPv4 cost mitigation

Author: snarayan-redhat

modules/installation-aws-permissions.adoc

@@ -307,3 +307,10 @@ If you are managing your cloud provider credentials with mint mode, the IAM user
 ====
 * `sts:AssumeRole`
 ====
+
+.Required permissions for enabling Bring your own public IPv4 addresses (BYOIP) feature for installation
+[%collapsible]
+====
+* `ec2:DescribePublicIpv4Pools`
+* `ec2:DisassociateAddress`
+====

modules/installation-configuration-parameters.adoc

@@ -1002,6 +1002,17 @@ For a private cluster, specify a private subnet for each availability zone.
 For clusters that use AWS Local Zones, you must add AWS Local Zone subnets to this list to ensure edge machine pool creation.
 |Valid subnet IDs.
 
+|platform:
+  aws:
+    publicIpv4Pool:
+|The public IPv4 pool ID that is used to allocate Elastic IPs (EIPs) when `publish` is set to `External`. You must provision and advertise the pool in the same {aws-short} account and region of the cluster. You must ensure that you have 2n + 1 IPv4 available in the pool where _n_ is the total number of {aws-short} zones used to deploy the Network Load Balancer (NLB) for API, NAT gateways, and bootstrap node. For more information about bring your own IP addresses (BYOIP) in {aws-short}, see link:https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-byoip.html#byoip-onboard[Onboard your BYOIP].
+| A valid link:https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-public-ipv4-pools.html[public IPv4 pool id]
+
+[NOTE]
+====
+BYOIP can be enabled only for customized installations that have no network restrictions.
+====
+
 |platform:
   aws:
     preserveBootstrapIgnition: