fd0f4a0365
6d224861 came from a --no-checkout worktree whose empty index made the
commit drop every file except two. This restores 05b50d2b's full tree and
correctly adds stacks/stem95su/gdrive-sync.tf + the service-catalog stem95su
entry. Forward-only (parent=6d224861, no force-push); [ci skip] since the
live infra was never applied from the broken commit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
116 lines
6.4 KiB
Markdown
116 lines
6.4 KiB
Markdown
# iDRAC monitoring: Redfish → SNMP migration (design)
|
||
|
||
**Date:** 2026-06-05
|
||
**Status:** approved (Viktor) — SNMP primary + thin Redfish remnant
|
||
**Stack:** `stacks/monitoring`
|
||
|
||
## Problem
|
||
|
||
The R730 iDRAC Redfish exporter (`idrac-redfish-exporter`, mrlhansen
|
||
`idrac_exporter`, image `viktorbarzin/idrac-redfish-exporter:2.4.1-voltage-fix`)
|
||
is configured `metrics: all: true`. It collects on-demand and walks every
|
||
Redfish subtree, making dozens of sequential ~1–2 s requests to a slow BMC.
|
||
|
||
Measured live (Prometheus `scrape_duration_seconds{job="redfish-idrac"}`, 24 h):
|
||
- **avg 18.5 s, peak 28.3 s**, occasional fast-fail 0.085 s.
|
||
- Pinned to a **3 m interval / 45 s timeout** because it cannot run at the 2 m
|
||
global cadence.
|
||
|
||
The cost is dominated by walks that feed **dashboard-only** panels (`memory`
|
||
10 DIMMs, `network`, `events`/SEL); the operationally important metrics (fan
|
||
speed, temps, power, voltage) come from cheap single-request collectors.
|
||
|
||
## Decision
|
||
|
||
Make **SNMP the fast primary source** and keep a **thin, slow Redfish remnant**
|
||
for the few things SNMP cannot serve. SNMP walks are fast (the `snmp-ups` job
|
||
runs at 30 s); the iDRAC SNMP agent is already enabled and reachable.
|
||
|
||
Rejected alternatives: (1) pure collector-trim of Redfish — still BMC-bound and
|
||
slow; (2) pure SNMP / retire Redfish — would require re-pointing the **external
|
||
ha-sofia** `sensor.r730_fan_speed` REST sensor (collides with a live session
|
||
editing the fan dashboard) and would drop two cosmetic panels.
|
||
|
||
## Key findings (ground-truthed)
|
||
|
||
- **The `snmp-idrac` job was dead.** It specified **no `module`** param, so
|
||
`snmp_exporter` defaulted to `if_mib` and returned only the iDRAC NIC's
|
||
interface counters — zero health/power/thermal. Both iDRAC jobs relabel to
|
||
`r730_idrac_*`, which hid this. The alert `iDRACSNMPMetricsMissing` is
|
||
**misnamed** — its expr `absent(r730_idrac_idrac_system_health)` checks a
|
||
*Redfish* metric.
|
||
- **A generated `dell_idrac` module already exists**, unmounted, in
|
||
`prometheus_snmp_chart_values.yaml` (~lines 79–1628). The mounted config is
|
||
`ups_snmp_values.yaml` (huawei/if_mib/ip_mib only). iDRAC SNMP = v2c,
|
||
community `Public0` (already the `public_v2` auth in `ups_snmp_values.yaml`).
|
||
- **Live snmpwalk (Public0, 192.168.1.4) confirms** these return real data:
|
||
fan RPM `coolingDeviceReading` (.4.700.12.1.6 = 7080 RPM), temps
|
||
`temperatureProbeReading` (.700.20.1.6, tenths-°C), system watts
|
||
`amperageProbeReading` (.600.30.1.6 = 252 W), PSU input voltage
|
||
`powerSupplyCurrentInputVoltage` (.600.12.1.16), PSU watts/health, global
|
||
health `globalSystemStatus` (.5.2.1), `systemState*` rollups (.200),
|
||
`physicalDisk*` status, `memoryDevice*` size/status/type/speed (.1100),
|
||
`networkDevice*` status/connection (.1100.90), BIOS `2.19.0` (.300.50.1.8),
|
||
model/service-tag (.5.1.3).
|
||
- **Genuine SNMP gaps — but inert or cosmetic today:**
|
||
- SSD life-left % (`physicalDiskRemainingRatedWriteEndurance` .49) → returns
|
||
`255` (N/A) for every drive incl. the Samsung SSD. **Redfish today reports
|
||
`0`** on the one drive that has it, and the SSD-wear alerts guard on `> 0`,
|
||
so they **already never fire** → no functional loss.
|
||
- SEL event log (`5.5.2`) → `NoSuchObject`. The `idrac_events_log_entry`
|
||
metric is **already empty in Prometheus** today → no loss.
|
||
- Indicator LED (`5.1.4`) → absent. Cosmetic ("Off") panel.
|
||
- NIC link-speed Mbps → no OID (health + up/down preserved). Cosmetic.
|
||
- Average watts → no native OID; reconstruct via PromQL `avg_over_time()`.
|
||
|
||
Conclusion: **every metric with real, used data today has an SNMP equivalent.**
|
||
|
||
## Naming / enum strategy
|
||
|
||
`snmp_exporter` names metrics after MIB objects (`temperatureProbeReading`,
|
||
`coolingDeviceReading`, `globalSystemStatus`, …) → after the `r730_idrac_`
|
||
relabel they are `r730_idrac_<mibName>`, different from today's
|
||
`r730_idrac_idrac_*` / `r730_idrac_redfish_*`. **Re-point consumers** (not
|
||
alias): aliasing via `metric_relabel_configs` only renames `__name__` and
|
||
cannot fix the label-set mismatch (Redfish `member_id`/`name` vs SNMP numeric
|
||
indexes) nor the **enum-value mismatch** (DellStatus `3=OK` vs Redfish `1`;
|
||
`systemPowerState 4=on` vs Redfish `2`). Alert exprs must change regardless, so
|
||
re-pointing is the honest path. The module adds `lookups:` so SNMP series carry
|
||
human labels (probe/fan location, disk display name) like today.
|
||
|
||
## Consumed-metric → SNMP mapping (DIRECT / REGEN / remnant)
|
||
|
||
REGEN = OID returns data but must be added to the module walk.
|
||
|
||
| Consumed (today) | Source after migration |
|
||
|---|---|
|
||
| fan health | REGEN `coolingDeviceStatus` .700.12.1.5 |
|
||
| consumed watts | DIRECT `amperageProbeReading` (System Board Pwr Consumption) |
|
||
| system health rollup | DIRECT `globalSystemStatus` .5.2.1 |
|
||
| PSU health | DIRECT `powerSupplyStatus`/`powerSupplySensorState` |
|
||
| memory health | DIRECT `systemStateMemoryDeviceStatusCombined` .200.10.1.27 |
|
||
| storage drive health | DIRECT `physicalDiskComponentStatus` .5.5.1.20.130.4.1.24 |
|
||
| **SSD life %** | **remnant** (SNMP=255 N/A; already inert) |
|
||
| system power state | DIRECT `systemPowerState` .5.2.4 (enum 4=on) |
|
||
| PSU input voltage | DIRECT `powerSupplyCurrentInputVoltage` .600.12.1.16 |
|
||
| system health (absent-probe) | DIRECT `globalSystemStatus` |
|
||
| **fan speed RPM (HA)** | DIRECT via remnant (HA reads exporter directly); SNMP REGEN `coolingDeviceReading` for Grafana |
|
||
| temperature | DIRECT `temperatureProbeReading` .700.20.1.6 (÷10) |
|
||
| avg watts | PromQL `avg_over_time(amperageProbeReading)` |
|
||
| **SEL log** | **remnant** (already empty) |
|
||
| machine/bios info | REGEN model/svctag .5.1.3, BIOS .300.50.1.8 |
|
||
| memory size / cpu count | DIRECT `memoryDeviceSize` (sum) / `processorDeviceStatus` (count) |
|
||
| **indicator LED** | **remnant** (cosmetic) |
|
||
| storage drive info/health/capacity | DIRECT `physicalDisk*` |
|
||
| memory module info/health/cap/speed | DIRECT(size) + REGEN(status/type/speed .1100.50.1.{5,7,8,15}) |
|
||
| network port health/link / **Mbps** | REGEN `networkDevice*` (.1100.90); **Mbps → remnant/drop** |
|
||
| PSU output/input/capacity watts | DIRECT `powerSupplyOutputWatts`/`RatedInputWattage` |
|
||
|
||
## Remnant role
|
||
|
||
The Redfish exporter stays alive (so the external ha-sofia
|
||
`sensor.r730_fan_speed` REST poll is **unchanged** — no ha-sofia edit, no
|
||
collision). It is trimmed to `sensors,system,network,storage,events` and its
|
||
Prometheus scrape slows to 10 m, keeping **only** the gap metrics (indicator
|
||
LED, NIC Mbps, SSD-life, SEL) via `metric_relabel_configs` to avoid duplicate
|
||
series with SNMP.
|