Race Condition in Public IP Allocation

[afritzler]

Description

When creating NATGateway and LoadBalancer resources in ironcore concurrently, the system assigns the same public IP to multiple entities.
This must never happen, as it breaks core network routing.

Expected Behavior

• Each resource gets a unique public IP.
• Allocation is atomic and free of race conditions.

Actual Behavior

• Multiple resources receive the same public IP.

Steps to Reproduce

1. Reduce the size of public IPs to e.g. a /30 IPv4 CIDR.
2. Create several NATGateway or LoadBalancer resources in parallel.
3. Check allocation logs → duplicated public IPs appear.

Severity

🚨 Critical

Definition of Done

• Public IP allocation is race-condition free.
• Add tests for concurrent resource creation.
• Improve allocator logging.