JobRejectedReason

Reasons a worker rejects a placement. See §4.1.

Zero-value trap: INSUFFICIENT_CAPACITY is 0, so an unset reason (or a value an older reader does not know) decodes as "insufficient capacity" — the one reason that makes the AutoManager wait for capacity rather than try elsewhere. Append new values; never renumber.

What each one tells the AutoManager: INSUFFICIENT_CAPACITY — the node is full right now; wait or place elsewhere. HARDWARE_UNAVAILABLE — a fact about THIS node (device missing, host port taken); exclude the node and place elsewhere. INVALID_SPEC — the job spec itself is wrong (missing required parameter, bad product template, tar sha mismatch, unrenderable compose); no node can run it, so end the job terminally — do not retry. UNKNOWN — unclassified; the AutoManager retries.