How to Monitor Apache HTTP Server Uptime with Vigilmon

Apache HTTP Server is the world's most widely deployed web server, powering everything from corporate intranets to high-traffic public websites. Yet most Apache monitoring stops at checking whether httpd is running — which completely misses the failures that matter most: a VirtualHost returning 500, an SSL certificate expiring in three days, a slow backend making every request time out, or a configuration reload that left Apache unable to bind its ports.

Vigilmon gives you external visibility into Apache HTTP Server uptime, response codes, latency, and SSL certificate health through HTTP probe monitoring and heartbeat checks. This tutorial covers the complete setup.

Why Apache Needs External Monitoring

Apache's built-in mod_status module exposes request rates, active connections, and worker slot counts — valuable for capacity planning, but not for uptime alerting. It cannot tell you:

Whether Apache is reachable from the public internet (your LAN monitoring might still reach it while external traffic can't)
Whether a specific VirtualHost is returning errors while the server process is running fine
Whether your SSL certificates are within days of expiry
Whether response times have climbed past acceptable thresholds for users
Whether Apache is serving the correct content (a misconfigured VirtualHost can return the default index page)

External monitoring from Vigilmon probes the paths your users actually hit, from network locations outside your infrastructure.

Step 1: Enable mod_status for Local Health Inspection

Enable mod_status for internal diagnostics (restrict to localhost — do not expose publicly):

# /etc/apache2/conf-enabled/server-status.conf  (Debian/Ubuntu)
# /etc/httpd/conf.d/server-status.conf           (RHEL/CentOS)

<Location "/server-status">
    SetHandler server-status
    Require local
    Require ip 127.0.0.1
</Location>

Reload Apache and verify locally:

apachectl configtest && systemctl reload apache2

curl http://127.0.0.1/server-status?auto
# Total Accesses: 42831
# Total kBytes: 394921
# CPULoad: .0123
# Uptime: 86401
# ReqPerSec: .496
# BytesPerSec: 4680
# BusyWorkers: 3
# IdleWorkers: 22

This gives you internal metrics. External monitoring through Vigilmon is what tells you when users can't reach your site at all.

Step 2: Add a Lightweight Health Endpoint

Create a dedicated health endpoint that Vigilmon can probe. This avoids checking your production URLs directly and gives you a clean 200/503 signal:

# Add to your VirtualHost configuration
<Location "/health">
    SetHandler None
    Options -All
    Require all granted
</Location>

Then create the health file:

echo "OK" > /var/www/html/health

Or, for a dynamic check that verifies Apache can process PHP or serve from disk:

<?php
// /var/www/html/health.php
http_response_code(200);
header('Content-Type: application/json');
echo json_encode([
    'status' => 'ok',
    'server' => 'apache',
    'timestamp' => date('c'),
]);

Test it:

curl -I http://localhost/health
# HTTP/1.1 200 OK
# Content-Type: text/plain

Step 3: Monitor Apache with Vigilmon

HTTP Uptime Monitor

Select HTTP / HTTPS as the monitor type
Set the URL to your health endpoint: https://your-domain.com/health
Set the check interval to 1 minute
Under Expected response, configure:
- Status code: 200
- (Optional) Response body contains: OK or "status":"ok"
Set the timeout to 5000ms — Apache requests taking longer than 5 seconds indicate a problem
Save the monitor

You can also add monitors for individual VirtualHosts if you host multiple sites:

https://site-a.example.com/health
https://site-b.example.com/health
https://api.example.com/health

Set Up Monitors via the Vigilmon API

If you're managing multiple Apache servers, use the Vigilmon API to create monitors programmatically:

curl -X POST https://api.vigilmon.online/v1/monitors \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Apache HTTP Server - Main",
    "type": "http",
    "url": "https://your-domain.com/health",
    "interval": 60,
    "timeout": 5000,
    "expected_status": 200,
    "regions": ["us-east", "eu-west", "ap-southeast"]
  }'

Response:

{
  "id": "mon_apache_01",
  "name": "Apache HTTP Server - Main",
  "status": "active",
  "url": "https://your-domain.com/health",
  "interval": 60,
  "uptime_7d": 100.0
}

Step 4: Monitor SSL Certificate Expiry

Apache sites almost always serve HTTPS. An expired certificate makes your site completely unreachable for users without a browser bypass.

Vigilmon monitors SSL certificates automatically when you add an HTTPS monitor. You'll receive an alert:

30 days before expiry
14 days before expiry
7 days before expiry

No configuration needed — just use the https:// scheme when adding your monitor.

You can also add a standalone SSL monitor to check expiry independent of your HTTP check:

Go to Monitors → New Monitor
Select SSL Certificate as the monitor type
Enter your domain: your-domain.com
Set alert thresholds (default: 30, 14, 7 days)
Save

If you run Apache with Let's Encrypt and certbot, the SSL monitor gives you advance warning if certbot renew has silently failed.

Step 5: Monitor Response Time and Latency

Slow responses are a failure mode too. Apache can return 200 while taking 8 seconds — technically "up" but effectively broken for users.

In your Vigilmon monitor settings:

Open the monitor for your Apache health endpoint
Go to Latency Alerting
Set a latency threshold, e.g. 2000ms (2 seconds)
Enable latency alerts to trigger if response time exceeds the threshold for 3 consecutive checks

This catches slow backends, runaway CGI scripts, or a full Apache worker pool making new requests queue up.

Step 6: Configure Alert Routing

When Apache goes down, you need immediate notification — not a daily digest.

Go to Alert Channels → Add Channel and configure one or more of:

Email — immediate notification to your on-call address
Webhook — integrate with Slack, PagerDuty, Opsgenie, or a custom handler
SMS — for critical infrastructure (paid plans)

Example webhook payload Vigilmon sends when Apache goes down:

{
  "monitor_name": "Apache HTTP Server - Main",
  "status": "down",
  "url": "https://your-domain.com/health",
  "error": "Connection timed out after 5000ms",
  "started_at": "2026-01-15T09:14:22Z",
  "checked_from": "us-east-1"
}

Assign the alert channel to your Apache monitors and set escalation rules — for example, page on-call only after 2 consecutive failures to avoid single-flap alerts.

Step 7: Add Monitors to a Public Status Page

If your Apache server hosts customer-facing applications, publish a status page so users can check availability without calling support.

In Vigilmon, go to Status Pages → New Status Page
Name it (e.g. "Service Status")
Add your Apache monitors as components:
- "Web Server" → Apache HTTP Server - Main
- "API" → Apache API endpoint
Publish

You get a public URL at https://status.vigilmon.online/your-page showing real-time uptime for each monitored component. Link it from your site's footer, your documentation, and your support portal.

Putting It All Together

Here's a summary of the monitoring setup for a typical Apache deployment:

| Monitor | Type | Check | Alert threshold | |---------|------|-------|----------------| | Apache main site | HTTP | /health → 200 | 1 consecutive failure | | SSL certificate | SSL | your-domain.com | 30 days before expiry | | Response latency | HTTP | /health < 2000ms | 3 consecutive slow responses | | API VirtualHost | HTTP | /api/health → 200 | 1 consecutive failure |

This gives you complete external visibility into Apache availability, SSL health, and performance — not just whether the process is running.

Get Started for Free

Vigilmon monitors Apache HTTP Server from multiple global regions with 1-minute check intervals, SSL certificate tracking, and instant alerts. The free tier includes up to 5 monitors with no credit card required.

Set up your first Apache monitor in under two minutes: vigilmon.online