The swarm openresty restart used 'container service update --force --detach' (fire-and-forget), so the deploy + e2e proceeded before openresty reconverged with prometheus.conf. The per-vhost log_by_lua then saw a nil metric_requests ('attempt to index global metric_requests') and the prometheus metricz/scrape e2e failed. Drop --detach so the update waits for convergence (bounded by the existing timeout 600). Also guard the per-vhost log_by_lua against a nil metric so any residual pre-init window can't throw.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>