[scotwells]

Requested by Scot Schuchert-Wells

What

The networkinterface and galactic-networkinterface controllers report reconcile errors for races that resolve on their own:

• The claim controller, galactic-networkinterface and Galactic all update status on the same NetworkInterface, claim and VPCAttachment, each from a cached copy. Whoever writes second gets a conflict.
• Short-lived guests are deleted while a reconcile is still running. The finalizer add, or a status write, then hits an object that no longer exists.
• A create can race the cache and return already-exists.

These errors keep the reconcile error floor alert firing. They don't point to any real fault.

Change

This follows the pattern the claim controller already uses:

• A conflict or already-exists now requeues with backoff instead of returning an error.
• A write to an interface, attachment or claim that was deleted mid-pass is a no-op. That includes the finalizer add.
• Every other error still surfaces.

Tests cover each case and confirm that other errors still surface. Each new test fails without the fix.

A later step could move each writer to server-side apply status with its own field manager. That would avoid the conflicts outright. It's left out here because it needs a managed-fields migration across two repos.

A companion Galactic change, datum-cloud/galactic#1375, handles the same races on its side.

[ecv]

Approve.

Same pattern as the claim controller and galactic#1375: a conflict, a cache-race already-exists, or a write to an object deleted mid-pass stops counting as a reconcile error, and every other error still surfaces. That takes routine races out of the error-floor alert without hiding real faults.

• Already-exists can only come from the two CreateOrUpdate calls (attachment, NAD), where it means the cache missed an object that exists. The requeue's Get then finds it and updates, so it cannot loop on a real collision.
• NotFound is swallowed only on the finalizer add and the three status writes, all after the object is gone; deletion handling and finalizer removal are untouched.
• The networkinterface controller reuses networkInterfaceClaimWriteRace, which matches conflicts only; the galactic one also takes already-exists, which fits its creates.

Follow-ups:

• Requeues log at V(1) only and carry no counter, so a pair of writers fighting forever would be invisible once the error floor stops seeing it. A conflict-requeue metric, as on galactic#1375, would keep that visible until the server-side apply move.

[kevwilliams]

Verified Requeue:true goes through the rate limiter so backoff holds, and each new test fails without its fix.