# Alertmanager → Hermes Webhook Integration

Session-verified setup guide for routing Prometheus/Alertmanager alerts
through the Hermes webhook platform for automatic RCA delivery to Telegram.

## Architecture

```
Prometheus (rules) → Alertmanager → Hermes Webhook (8644) → Agent RCA → Telegram
```

The old Telegram-bridge-bot is replaced. Every alert triggers an agent run
that performs root-cause analysis and posts findings to the user's chat.

## Components

- **Prometheus**: scrapes exporters, evaluates alerting rules, fires alerts
- **Alertmanager**: deduplicates, groups, routes alerts to receivers
- **Hermes Webhook**: receives Alertmanager POST, triggers agent run
- **Agent**: analyzes alert payload, investigates Prometheus/APIs, delivers RCA

## Step-by-Step Setup

### 1. Hermes Webhook Subscription

```bash
hermes webhook subscribe alertmanager-rca \
  --prompt 'Alertmanager Event - Status: {status}
Severity: {commonLabels.severity}
Alert: {commonLabels.alertname}
Instance: {commonLabels.instance}
Summary: {commonAnnotations.summary}
Description: {commonAnnotations.description}

Perform a root cause analysis. Investigate the affected system using available
tools (Prometheus queries, SSH to hosts, API calls). Report findings concisely.' \
  --description "Alertmanager alerts → automatic RCA" \
  --deliver telegram \
  --deliver-chat-id "<your-chat-id>"
```

**Alertmanager payload structure** (top-level fields available in templates):
- `status` — "firing" or "resolved"
- `commonLabels` — merged labels across all alerts in the group
- `commonAnnotations` — merged annotations
- `alerts` — array of individual alert objects (NOT templatable with dot notation)
- `groupKey`, `receiver`, `externalURL`

### 2. Alertmanager Configuration

```yaml
route:
  receiver: hermes-rca
  group_by: ['alertname', 'instance']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 4h

receivers:
  - name: hermes-rca
    webhook_configs:
      - url: http://<hermes-ip>:8644/webhooks/alertmanager-rca
        send_resolved: true
        max_alerts: 0
```

Push to the monitoring container and reload:
```bash
# Config is typically mounted from host filesystem
# Adjust path to your setup
CONFIG_B64=$(base64 -w0 alertmanager.yml)
ssh root@<proxmox-host> "echo '$CONFIG_B64' | base64 -d | \
  pct exec <ct-id> -- tee /opt/monitoring/alertmanager/alertmanager.yml >/dev/null && \
  pct exec <ct-id> -- bash -lc 'docker restart alertmanager'"
```

### 3. Prometheus Alerting Rules

Copy `templates/alerting_rules.yml` to the Prometheus rules directory and reload:
```bash
RULES_B64=$(base64 -w0 alerting_rules.yml)
ssh root@<proxmox-host> "echo '$RULES_B64' | base64 -d | \
  pct exec <ct-id> -- tee /opt/monitoring/prometheus/rules/alerting_rules.yml >/dev/null && \
  pct exec <ct-id> -- bash -lc 'docker exec prometheus wget -qO- --post-data= http://localhost:9090/-/reload'"
```

### 4. Verification

```bash
# Check rules loaded
curl -s http://localhost:9090/api/v1/rules | python3 -m json.tool | head -40

# Check active alerts
curl -s http://localhost:9090/api/v1/alerts | python3 -m json.tool

# Check alertmanager sees the same alerts
curl -s http://localhost:9093/api/v2/alerts | python3 -m json.tool

# Test webhook end-to-end
hermes webhook test alertmanager-rca --payload '{"status":"firing","commonLabels":{"alertname":"TestAlert","severity":"warning"},"commonAnnotations":{"summary":"Test","description":"Testing webhook"}}'
```

## Critical Pitfalls

### 0. Webhook Agent Has No Investigation Tools (MOST COMMON FAILURE)

**Symptom**: Alert arrives via webhook, agent responds but says "I don't have
shell/curl/terminal tools available" and cannot perform RCA.

**Root Cause**: The default `hermes-webhook` toolset
(`_HERMES_WEBHOOK_SAFE_TOOLS` in `toolsets.py`) only includes `web_search`,
`web_extract`, `vision_analyze`, and `clarify` — no terminal, no file, no SSH.
This is intentional for security (webhook payloads are untrusted) but makes
local investigation impossible.

**Fix**: Add `webhook` to `platform_toolsets` in `~/.hermes/config.yaml`:
```yaml
platform_toolsets:
  webhook:
    - browser
    - code_execution
    - delegation
    - file
    - memory
    - session_search
    - skills
    - terminal
    - todo
    - vision
    - web
```
Then restart the gateway (from a SEPARATE shell — cannot restart from inside
the gateway process). Use a one-shot cronjob if no external shell is available:
```
cronjob(action='create', schedule='1m', prompt='systemctl --user restart hermes-gateway')
```

### 1. PVE Alert Storm (624 false alerts)

**Symptom**: Hundreds of `PVEHAServiceDegraded` or `PVENodeDown` alerts fire
immediately after enabling rules.

**Root Cause**: The `pve_up` and `pve_ha_state` metrics include ALL guests
(including intentionally stopped VMs/CTs) and ALL HA states (15 states per
guest). Without filtering:

- `pve_up == 0` matches every stopped guest (dozens)
- `pve_ha_state != 1` matches every non-started state × every guest (600+)

**Fix**: Filter rules strictly:
```yaml
# Only alert on actual PVE NODES, not guests
expr: pve_up{id=~"node/.*"} == 0

# Only alert on real error states
expr: pve_ha_state{state=~"error|fence|freeze|gone"} == 1
```

### 2. Stale Alerts in Alertmanager After Rule Changes

**Symptom**: Old alerts remain in Alertmanager's API even after Prometheus
stops firing them.

**Root Cause**: Alertmanager caches alerts and waits for Prometheus to send
"resolved" notifications. If the rule that generated them no longer exists,
Prometheus never sends the resolution.

**Fix**: Restart Alertmanager to flush its cache:
```bash
docker restart alertmanager
```

### 3. Blackbox ICMP False Positives

**Symptom**: `HostUnreachableICMP` fires for a host that is actually
reachable via TCP.

**Root Cause**: Many cloud providers and firewalls block ICMP echo requests
while allowing TCP traffic. PBS Remote (noris nbg1) is a typical example.

**Fix**: Either whitelist ICMP on the target firewall, or switch the
Blackbox probe from ICMP to TCP port check:
```yaml
# In blackbox.yml, use tcp module instead of icmp
modules:
  tcp_connect:
    prober: tcp
    timeout: 5s
    tcp:
      tls: false
```

### 4. File Transfer to LXC Containers

`scp` and `pct push` often fail with permission errors. The reliable method
is base64 encoding through SSH pipes:

```bash
# Encode locally, decode remotely
B64=$(base64 -w0 /local/file.py)
ssh root@<pve-host> "echo '$B64' | base64 -d | \
  pct exec <ct-id> -- tee /remote/path/file.py >/dev/null"
```

### 5. Docker Container Config Reload

When config files are bind-mounted from the host, edit the HOST file (not
inside the container). Then reload:

```bash
# Prometheus (hot reload via HTTP)
docker exec prometheus wget -qO- --post-data= http://localhost:9090/-/reload

# Alertmanager (hot reload via HTTP)
docker exec alertmanager wget -qO- --post-data= http://localhost:9093/-/reload

# If hot reload fails, restart the container
docker restart prometheus
docker restart alertmanager
```

## RCA Workflow

When an alert arrives via webhook, the agent should:

1. **Parse the alert** — extract alertname, severity, instance, summary
2. **Query Prometheus** — check related metrics, history, correlated alerts
3. **Investigate the root cause** — SSH to affected hosts, check logs, APIs
4. **Report findings** — concise summary with root cause and recommended fix

Example RCA script pattern (runs inside the monitoring container):
```python
import json, urllib.request, urllib.parse, socket

PROM = "http://127.0.0.1:9090"

def q(expr):
    url = f"{PROM}/api/v1/query?query={urllib.parse.quote(expr)}"
    with urllib.request.urlopen(url, timeout=5) as r:
        d = json.loads(r.read())
    return d.get("data", {}).get("result", [])

# Check probe success, HTTP status, TCP reachability
# Cross-reference with direct curl/socket connections
```

## Key Metrics Reference

| Metric | What it measures | Alert threshold |
|--------|-----------------|----------------|
| `up{job="node_exporter"}` | Node reachability | `== 0` for 2m |
| `pve_up{id=~"node/.*"}` | PVE node status (FILTER!) | `== 0` for 2m |
| `pve_ha_state{state=~"error\|fence\|freeze\|gone"}` | HA error states only | `== 1` for 1m |
| `ceph_health_status` | Cluster health (0=OK,1=WARN,2=ERR) | `>= 1` |
| `mysql_up` | Galera node alive | `== 0` for 1m |
| `mysql_global_status_wsrep_cluster_size` | Galera nodes connected | `< 3` for 2m |
| `probe_success{job="blackbox_icmp"}` | ICMP reachability | `== 0` for 2m |
| `probe_success{job="blackbox_http"}` | HTTP endpoint | `== 0` for 2m |

## Infrastructure Layout (Reference)

- Proxmox host: `10.0.20.70`, SSH key: `~/.ssh/id_ed25519_proxmox`
- Monitoring container: LXC CT 141 (IP `10.0.30.141`)
- Prometheus: `localhost:9090` (in CT141 Docker)
- Grafana: `localhost:3000` (in CT141 Docker, admin/Grafana2026!)
- Alertmanager: `localhost:9093` (in CT141 Docker)
- Hermes Gateway: `10.0.30.230:8644`
- Telegram chat ID: `223926918`
- PVE exporter: `pve-exporter:9221` (job `pve_api`)
- Ceph exporter: `10.0.20.70:9283` (job `ceph`)
- Galera nodes: `10.0.30.71/72/73` (job `mysqld_exporter`)
- PBS Remote: `213.95.54.60:8007` (job `pbs-remote`, ICMP blocked)