---
phase: 08-observability-stack
plan: 03
subsystem: infra
tags: [prometheus, grafana, loki, alertmanager, servicemonitor, observability, kubernetes]

# Dependency graph
requires:
  - phase: 08-01
    provides: TaskPlanner /metrics endpoint and ServiceMonitor
  - phase: 08-02
    provides: Grafana Alloy for log collection
provides:
  - End-to-end verified observability stack
  - Prometheus scraping TaskPlanner metrics
  - Loki log queries verified in Grafana
  - Alerting rules confirmed (KubePodCrashLooping)
affects: [operations, future-monitoring, troubleshooting]

# Tech tracking
tech-stack:
  added: []
  patterns: [datasource-conflict-resolution]

key-files:
  created: []
  modified:
    - loki-stack ConfigMap (isDefault fix)

key-decisions:
  - "Loki datasource isDefault must be false when Prometheus is default datasource"

patterns-established:
  - "Datasource conflict: Only one Grafana datasource can have isDefault: true"

# Metrics
duration: 6min
completed: 2026-02-03
---

# Phase 8 Plan 03: Observability Verification Summary

**End-to-end observability verified: Prometheus scraping TaskPlanner metrics, Loki log queries working, dashboards operational**

## Performance

- **Duration:** 6 min
- **Started:** 2026-02-03T21:38:00Z (approximate)
- **Completed:** 2026-02-03T21:44:08Z
- **Tasks:** 3 (2 auto, 1 checkpoint)
- **Files modified:** 1 (loki-stack ConfigMap patch)

## Accomplishments

- ServiceMonitor deployed and Prometheus scraping TaskPlanner /metrics endpoint
- KubePodCrashLooping alert rule confirmed present in kube-prometheus-stack
- Alertmanager running and responsive
- Human verified: Grafana TLS working, dashboards showing metrics, Loki log queries returning TaskPlanner logs

## Task Commits

Each task was committed atomically:

1. **Task 1: Deploy TaskPlanner with ServiceMonitor and verify Prometheus scraping** - `91f91a3` (fix: add release label for Prometheus discovery)
2. **Task 2: Verify critical alert rules exist** - no code changes (verification only)
3. **Task 3: Human verification checkpoint** - user verified

**Plan metadata:** pending

## Files Created/Modified

- `loki-stack ConfigMap` (in-cluster) - Patched isDefault from true to false to resolve datasource conflict

## Decisions Made

- Added `release: kube-prometheus-stack` label to ServiceMonitor to match Prometheus Operator's serviceMonitorSelector
- Patched Loki datasource isDefault to false to allow Prometheus as default (Grafana only supports one default)

## Deviations from Plan

### Auto-fixed Issues

**1. [Rule 1 - Bug] Fixed Loki datasource conflict causing Grafana crash**
- **Found during:** Task 1 (verifying Grafana accessibility)
- **Issue:** Both Prometheus and Loki datasources had `isDefault: true`, causing Grafana to crash with "multiple default datasources" error. User couldn't see any datasources.
- **Fix:** Patched loki-stack ConfigMap to set `isDefault: false` for Loki datasource
- **Command:** `kubectl patch configmap loki-stack-datasource -n monitoring --type merge -p '{"data":{"loki-stack-datasource.yaml":"...isDefault: false..."}}'`
- **Verification:** Grafana restarted, both datasources now visible and queryable
- **Committed in:** N/A (in-cluster configuration, not git-tracked)

---

**Total deviations:** 1 auto-fixed (1 bug)
**Impact on plan:** Essential fix for Grafana usability. No scope creep.

## Issues Encountered

- ServiceMonitor initially not discovered by Prometheus - resolved by adding `release: kube-prometheus-stack` label to match selector
- Grafana crashing on startup due to datasource conflict - resolved via ConfigMap patch

## OBS Requirements Verified

| Requirement | Description | Status |
|-------------|-------------|--------|
| OBS-01 | Prometheus collects cluster metrics | Verified |
| OBS-02 | Grafana dashboards display cluster metrics | Verified |
| OBS-03 | Loki stores application logs | Verified |
| OBS-04 | Alloy collects and forwards logs | Verified |
| OBS-05 | Grafana can query logs from Loki | Verified |
| OBS-06 | Critical alerts configured (KubePodCrashLooping) | Verified |
| OBS-07 | Grafana TLS via Traefik | Verified |
| OBS-08 | TaskPlanner /metrics endpoint | Verified |

## User Setup Required

None - all configuration applied to cluster. No external service setup required.

## Next Phase Readiness

- Phase 8 (Observability Stack) complete
- Ready for Phase 9 (Security Hardening) or ongoing operations
- Observability foundation established for production monitoring

---
*Phase: 08-observability-stack*
*Completed: 2026-02-03*