A pooled backend entry pointing at a remote host has no child process, so
the 'exit' handler that clears a dead local backend never fires. The
renderer's 60s keepalive touch also spares it from the idle reaper. Nothing
was left to retire the descriptor, so once the host went away the pool kept
serving it and every profile bound to that host stayed broken until restart.
Pooled remote descriptors now share the primary's liveness policy: probed on
the same revalidate tick, keyed per base URL, and dropped only after the
same consecutive-failure limit, so the next ensureBackend() rebuilds.
Co-authored-by: Rodrigo Fernandez <rod@nxtlevel.dev>
Brooklyn Nicholson
Gille