This change modifies the validation logic for ServiceCIDR updates
(`ValidateServiceCIDRUpdate`) to specifically permit upgrading a
single-stack ServiceCIDR (either IPv4 or IPv6) to a dual-stack
configuration.
This reconfiguration path is considered safe because it only involves adding
a new CIDR range without altering the existing primary CIDR. This
ensures that existing Service IP allocations are not disrupted.
Other modifications, such as:
- Downgrading from dual-stack to single-stack
- Reordering CIDRs in a dual-stack configuration
- Changing the primary CIDR during a single-to-dual-stack
reconfiguration
remain disallowed by the validation. These operations carry a higher
risk of breaking existing Services or cluster networking
configurations. Preventing these updates automatically encourages
administrators to perform such changes manually after carefully
assessing the potential impact on their specific cluster environment.
The validation errors and controller logs provide guidance when such
disallowed changes are attempted.
Change-Id: I41dc09dfddb05f277925da2262f8114d6accbd1d
0266d3bcb3