Files
nixos-servers/docs/plans/completed/monitoring-migration-victoriametrics.md
Torjus Håkestad a6013d3950
Some checks failed
Run nix flake check / flake-check (push) Failing after 6m25s
Run nix flake check / flake-check (pull_request) Failing after 3m52s
monitoring02: enable alerting and migrate CNAMEs from http-proxy
- Switch vmalert from blackhole mode to sending alerts to local
  Alertmanager
- Import alerttonotify service so alerts route to NATS notifications
- Move alertmanager and grafana CNAMEs from http-proxy to monitoring02
- Add monitoring CNAME to monitoring02
- Add Caddy reverse proxy entries for alertmanager and grafana
- Remove prometheus, alertmanager, and grafana Caddy entries from
  http-proxy (now served directly by monitoring02)
- Move monitoring02 Vault AppRole to hosts-generated.tf with
  extra_policies support and prometheus-metrics policy
- Update Promtail to use authenticated loki.home.2rjus.net endpoint
  only (remove unauthenticated monitoring01 client)
- Update pipe-to-loki and bootstrap to use loki.home.2rjus.net with
  basic auth from Vault secret
- Move migration plan to completed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-17 21:23:21 +01:00

157 lines
6.8 KiB
Markdown

# Monitoring Stack Migration to VictoriaMetrics
## Overview
Migrate from Prometheus to VictoriaMetrics on a new host (monitoring02) to gain better compression
and longer retention. Run in parallel with monitoring01 until validated, then switch over using
a `monitoring` CNAME for seamless transition.
## Current State
**monitoring02** (10.69.13.24) - **PRIMARY**:
- 4 CPU cores, 8GB RAM, 60GB disk
- VictoriaMetrics with 3-month retention
- vmalert with alerting enabled (routes to local Alertmanager)
- Alertmanager -> alerttonotify -> NATS notification pipeline
- Grafana with Kanidm OIDC (`grafana.home.2rjus.net`)
- Loki (log aggregation)
- CNAMEs: monitoring, alertmanager, grafana, grafana-test, metrics, vmalert, loki
**monitoring01** (10.69.13.13) - **SHUT DOWN**:
- No longer running, pending decommission
## Decision: VictoriaMetrics
Per `docs/plans/long-term-metrics-storage.md`, VictoriaMetrics is the recommended starting point:
- Single binary replacement for Prometheus
- 5-10x better compression (30 days could become 180+ days in same space)
- Same PromQL query language (Grafana dashboards work unchanged)
- Same scrape config format (existing auto-generated configs work)
If multi-year retention with downsampling becomes necessary later, Thanos can be evaluated.
## Architecture
```
┌─────────────────┐
│ monitoring02 │
│ VictoriaMetrics│
│ + Grafana │
monitoring │ + Loki │
CNAME ──────────│ + Alertmanager │
│ (vmalert) │
└─────────────────┘
│ scrapes
┌───────────────┼───────────────┐
│ │ │
┌────┴────┐ ┌─────┴────┐ ┌─────┴────┐
│ ns1 │ │ ha1 │ │ ... │
│ :9100 │ │ :9100 │ │ :9100 │
└─────────┘ └──────────┘ └──────────┘
```
## Implementation Plan
### Phase 1: Create monitoring02 Host [COMPLETE]
Host created and deployed at 10.69.13.24 (prod tier) with:
- 4 CPU cores, 8GB RAM, 60GB disk
- Vault integration enabled
- NATS-based remote deployment enabled
- Grafana with Kanidm OIDC deployed as test instance (`grafana-test.home.2rjus.net`)
### Phase 2: Set Up VictoriaMetrics Stack [COMPLETE]
New service module at `services/victoriametrics/` for VictoriaMetrics + vmalert + Alertmanager.
Imported by monitoring02 alongside the existing Grafana service.
1. **VictoriaMetrics** (port 8428):
- `services.victoriametrics.enable = true`
- `retentionPeriod = "3"` (3 months)
- All scrape configs migrated from Prometheus (22 jobs including auto-generated)
- Static user override (DynamicUser disabled) for credential file access
- OpenBao token fetch service + 30min refresh timer
- Apiary bearer token via vault.secrets
2. **vmalert** for alerting rules:
- Points to VictoriaMetrics datasource at localhost:8428
- Reuses existing `services/monitoring/rules.yml` directly via `settings.rule`
- Notifier sends to local Alertmanager at localhost:9093
3. **Alertmanager** (port 9093):
- Same configuration as monitoring01 (alerttonotify webhook routing)
- alerttonotify imported on monitoring02, routes alerts via NATS
4. **Grafana** (port 3000):
- VictoriaMetrics datasource (localhost:8428) as default
- Loki datasource pointing to localhost:3100
5. **Loki** (port 3100):
- Same configuration as monitoring01 in standalone `services/loki/` module
- Grafana datasource updated to localhost:3100
**Note:** pve-exporter and pushgateway scrape targets are not included on monitoring02.
pve-exporter requires a local exporter instance; pushgateway is replaced by VictoriaMetrics
native push support.
### Phase 3: Parallel Operation [COMPLETE]
Ran both monitoring01 and monitoring02 simultaneously to validate data collection and dashboards.
### Phase 4: Add monitoring CNAME [COMPLETE]
Added CNAMEs to monitoring02: monitoring, alertmanager, grafana, metrics, vmalert, loki.
### Phase 5: Update References [COMPLETE]
- Moved alertmanager, grafana, prometheus CNAMEs from http-proxy to monitoring02
- Removed corresponding Caddy reverse proxy entries from http-proxy
- monitoring02 Caddy serves alertmanager, grafana, metrics, vmalert directly
### Phase 6: Enable Alerting [COMPLETE]
- Switched vmalert from blackhole mode to local Alertmanager
- alerttonotify service running on monitoring02 (NATS nkey from Vault)
- prometheus-metrics Vault policy added for OpenBao scraping
- Full alerting pipeline verified: vmalert -> Alertmanager -> alerttonotify -> NATS
### Phase 7: Cutover and Decommission [IN PROGRESS]
- monitoring01 shut down (2026-02-17)
- Vault AppRole moved from approle.tf to hosts-generated.tf with extra_policies support
**Remaining cleanup (separate branch):**
- [ ] Update `system/monitoring/logs.nix` - Promtail still points to monitoring01
- [ ] Update `hosts/template2/bootstrap.nix` - Bootstrap Loki URL still points to monitoring01
- [ ] Remove monitoring01 from flake.nix and host configuration
- [ ] Destroy monitoring01 VM in Proxmox
- [ ] Remove monitoring01 from terraform state
- [ ] Remove or archive `services/monitoring/` (Prometheus config)
## Completed
- 2026-02-08: Phase 1 - monitoring02 host created
- 2026-02-17: Phase 2 - VictoriaMetrics, vmalert, Alertmanager, Loki, Grafana configured
- 2026-02-17: Phase 6 - Alerting enabled, CNAMEs migrated, monitoring01 shut down
## VictoriaMetrics Service Configuration
Implemented in `services/victoriametrics/default.nix`. Key design decisions:
- **Static user**: VictoriaMetrics NixOS module uses `DynamicUser`, overridden with a static
`victoriametrics` user so vault.secrets and credential files work correctly
- **Shared rules**: vmalert reuses `services/monitoring/rules.yml` via `settings.rule` path
reference (no YAML-to-Nix conversion needed)
- **Scrape config reuse**: Uses the same `lib/monitoring.nix` functions and
`services/monitoring/external-targets.nix` as Prometheus for auto-generated targets
## Notes
- VictoriaMetrics uses port 8428 vs Prometheus 9090
- PromQL compatibility is excellent
- VictoriaMetrics native push replaces Pushgateway (remove from http-proxy if not needed)
- monitoring02 deployed via OpenTofu using `create-host` script
- Grafana dashboards defined declaratively via NixOS, not imported from monitoring01 state
- Tempo and Pyroscope deferred (not actively used; can be added later if needed)