Describe the problem/challenge you have

The webhook blocks the modification of the IP range for an ExternalIPPool, as it might lead to conflicts with resources already allocated from the original range. This is a safety measure to prevent accidental or unexpected reallocation or loss of IP addresses. However it blocks the allocation even if no resources are created with it.

Describe the solution you'd like

The webhook should verify whether any IP addresses within the original range are currently allocated (e.g., by Egress or other resources) before allowing the range to be modified. If no resources are using IPs in the area being shrunk/expanded, the webhook would allow it.

Anything else you would like to add?

Examples-
../ExternalIpPools.yaml": admission webhook "externalippoolvalidator.antrea.io" denied the request: existing IPRanges [192.168.100.10-192.168.100.200] cannot be deleted