Operator supplied the topology: "the entire rack is on the same circuit,
public ip is served by firewall on the same circuit. load tripped
breaker, entire rack goes dark."
That inverts the argument I committed one commit ago in 3cc55b4. I held
the load attribution partly because a site-wide blackout looked like too
large a blast radius for one GPU box. It is not — it is exactly the
blast radius a shared circuit predicts. The observation I treated as
unexplained was the signature of the mechanism.
Kept the wrong version visible with a superseded marker rather than
editing it away, per the superseded-claims convention: the reasoning
circulated in two althing messages and a peer adopted it.
Holding the attribution as unmeasured was still correct; the argument
used to hold it was reasoning about wiring neither side had seen and
neither side asked for.
Records the finding that outlives the incident: the same circuit powers
ana-ml2, ana-gw, ana-wg, ana-nas and the BMCs, so the load takes every
recovery path with it. Composed with ana-gw's WAN admin being closed
(tunnel-only) and the tunnel terminating on ana-wg, there is no remote
management path to Anaheim during a rack power event, in-band or out.
Open question for the weekend triage: is any of that rack on UPS or a
second circuit?
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