Monitoring Ilograph with Vigilmon

Ilograph is an interactive architecture diagramming tool that lets engineers create rich, navigable system diagrams with perspectives and zoom levels. Self-hosted Ilograph deployments give teams full control over their architecture documentation — but self-hosting means owning the uptime. When your Ilograph server is unreachable, diagrams can't load and teams lose visibility into system architecture. Vigilmon monitors your Ilograph instance continuously so you find out before your engineers do.

What You'll Set Up

• HTTP uptime monitor for the Ilograph web application
• Keyword check to confirm diagram content loads correctly
• TCP port check for network-level connectivity
• SSL certificate expiry alerts for your Ilograph domain
• Heartbeat monitoring for diagram export and rendering workers

Prerequisites

• Self-hosted Ilograph instance running (Docker or Node.js)
• Ilograph accessible over HTTP or HTTPS on a domain or IP
• A free Vigilmon account

Step 1: Monitor the Ilograph Web Application

The Ilograph frontend is the interface your engineers use to load and navigate architecture diagrams. If this endpoint is unreachable, no one can view or update system documentation.

1. Log in to vigilmon.online and click Add Monitor.
2. Set Type to HTTP / HTTPS.
3. Enter your Ilograph URL: https://ilograph.yourdomain.com.
4. Set Check interval to 1 minute.
5. Set Expected HTTP status to 200.
6. Click Save.

If Ilograph is running behind a reverse proxy (nginx, Caddy, Traefik), the HTTP check confirms both the proxy and the Ilograph process are healthy. A 502 Bad Gateway response indicates the Ilograph container has crashed even though the proxy is still accepting connections.

Step 2: Verify the Ilograph Application Loads Correctly

An HTTP 200 response confirms the server is responding, but it doesn't confirm the Ilograph application actually initialized. Add a keyword check to catch misconfigured deployments:

1. Open your Ilograph HTTP / HTTPS monitor.
2. Under Advanced, set Expected body contains to ilograph — this string appears in every Ilograph HTML page.
3. Click Save.

A misconfigured environment variable, missing static asset, or failed initialization can cause Ilograph to serve a blank or error page with a 200 status. The keyword check catches this class of failure before your team reports that diagrams won't load.

Step 3: Add a TCP Port Check

Ilograph typically serves on port 443 or 80. A TCP port monitor provides a low-level connectivity check independent of the HTTP layer:

1. Add Monitor → TCP Port.
2. Host: ilograph.yourdomain.com, Port: 443 (or 80 for HTTP-only deployments).
3. Set Check interval to 2 minutes.
4. Click Save.

TCP-level checks catch network failures — firewall rule changes, container networking misconfigurations, or port binding conflicts — that occur before any HTTP response is generated. A TCP timeout when the HTTP monitor returns 200 indicates a split-horizon DNS or routing issue worth investigating.

Step 4: Add SSL Certificate Monitoring

A lapsed TLS certificate blocks all Ilograph access immediately with a browser security error. Engineers may interpret this as a full server outage and escalate before you've had a chance to investigate.

1. Open your Ilograph HTTP / HTTPS monitor.
2. Enable Monitor SSL certificate under the SSL section.
3. Set Alert when certificate expires in less than 21 days.
4. Click Save.

A 21-day lead time gives you three weeks to renew or investigate Let's Encrypt auto-renewal failures — enough runway to resolve ACME challenge issues, DNS propagation delays, or certificate authority problems without impacting users.

Step 5: Heartbeat Monitoring for Diagram Export Workers

Ilograph deployments often include background export processes that render diagrams to PNG, SVG, or PDF. Use Vigilmon's cron heartbeat to confirm these workers are running.

1. In Vigilmon, click Add Monitor → Cron Heartbeat.
2. Set the expected ping interval to match your export worker schedule (e.g. 60 minutes for an hourly health ping).
3. Copy the heartbeat URL (e.g. https://vigilmon.online/heartbeat/abc123).
4. Add the ping to the end of your export worker health check script:

#!/bin/bash
# Check that the Ilograph export worker is healthy
curl -sf http://localhost:9000/export/health && \
  curl -s https://vigilmon.online/heartbeat/abc123

Or as a Docker Compose health check with a post-check heartbeat:

services:
  ilograph-export:
    image: ilograph/export-worker
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:9000/export/health"]
      interval: 60s
      timeout: 10s
      retries: 3

Add a companion script that pings your Vigilmon heartbeat URL after a successful health check to confirm the export process is functioning end-to-end.

Step 6: Configure Alert Channels

1. Go to Alert Channels in Vigilmon and add Slack, email, or a webhook endpoint for your on-call rotation.
2. Set Consecutive failures before alert to 2 on the main Ilograph monitor — container restarts and brief probe misses can cause single false positives.
3. Use Maintenance windows to suppress alerts during Ilograph version upgrades:

# Pause alerts during upgrade
curl -X POST https://vigilmon.online/api/maintenance \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"monitor_id": "abc123", "duration_minutes": 15}'

docker pull ilograph/server && docker compose up -d

Summary

| Monitor | Target | What It Catches | |---|---|---| | Web application | https://ilograph.yourdomain.com | Frontend down, proxy failure | | Keyword check | Page body contains ilograph | Blank page, initialization failure | | TCP port | :443 | Network-level connectivity failure | | SSL certificate | Ilograph domain | Certificate renewal failure | | Cron heartbeat | Heartbeat URL | Export worker crash |

Ilograph turns architecture documentation into an interactive, navigable experience — but self-hosted means you own the reliability. With Vigilmon monitoring the HTTP frontend, page content, TCP connectivity, SSL certificate, and export workers, you'll catch failures in real time rather than learning about them when an engineer can't load a system diagram during an incident review.