monitoring: derive nginx_exporter_listen from per-host wg_ip#39
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The default `nginx_exporter_listen: "10.10.0.2:9113"` hardcoded the first RU's WG address. With multiple RUs in groups['ru'] (live as of 2026-05-06), the second RU tried to bind 10.10.0.2:9113 — an address not assigned to its interface — and entered a systemd restart loop: HTTP server failed: listen tcp 10.10.0.2:9113: bind: cannot assign requested address vmagent's scrape_configs already uses `hostvars[h].wg_ip | default(wg_ru_ip)` per-host (vmagent-scrape.yml.j2), and node_exporter's listen address derives the same way. Bring nginx_exporter into line with that pattern so a fresh role apply on any RU produces a unit file that binds the local WG IP. Behaviour: * vm_my_ru (wg_ip=10.10.0.2) → listen 10.10.0.2:9113 (unchanged) * vm_my_ru2 (wg_ip=10.10.0.3) → listen 10.10.0.3:9113 (was broken) * future RUs auto-correct from inventory entry. Tested by re-deploying on vm_my_ru2: service active, port bound, metrics flow to vmagent → VictoriaMetrics. Grafana dashboards already group by instance label so multi-RU panels populate automatically. Signed-off-by: findias <findias@gmail.com>
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Why
nginx_exporter_listendefaulted to a hardcoded10.10.0.2:9113— the first RU's WG address. With multiple RUs ingroups['ru'](live as of 2026-05-06), the second RU tried to bind to an address not assigned to its interface and entered a systemd restart loop:Fix
Derive listen address from per-host
wg_ipwith the samedefault(wg_ru_ip)fallback that scrape configs and node_exporter already use:vmagent's
vmagent-scrape.yml.j2already iteratesgroups['ru']with the same expression, so listening + scraping stay in lockstep on each RU.Behaviour
vm_my_ru(wg_ip=10.10.0.2) → listen10.10.0.2:9113(unchanged)vm_my_ru2(wg_ip=10.10.0.3) → listen10.10.0.3:9113(was broken)Test plan
vm_my_ru2: service goes fromactivating(restart loop) toactive, port binds, metrics return.groups['ru']loop, pushes to VictoriaMetrics.up{job="nginx-vm_my_ru2", instance="5.8.50.41"}reports.vm_my_rucontinues to work becausewg_ip: 10.10.0.2in inventory matches the previous hardcoded default — the new expression resolves to the same value for it.