Agent-Based Monitoring: Why You Need Eyes Inside Your Servers

Who This Is For

This guide is for DevOps engineers, system administrators, and developers who want to understand agent-based monitoring and whether they need it for their infrastructure.

If you're wondering whether to install a monitoring agent on your servers, this guide will help you decide.

What Is Agent-Based Monitoring?

Agent-based monitoring uses a small software program (the "agent") installed directly on your servers. The agent:

1. Runs continuously on the server
2. Collects metrics about system resources
3. Sends data to a central monitoring platform
4. Enables deep visibility not possible from outside

How It Works

┌─────────────────────────────────────┐
│           Your Server               │
│  ┌─────────────────────────────┐   │
│  │     Monitoring Agent        │   │
│  │  • Reads /proc/cpuinfo      │   │
│  │  • Reads /proc/meminfo      │   │
│  │  • Reads disk stats         │   │
│  │  • Monitors processes       │   │
│  └─────────────┬───────────────┘   │
└────────────────┼───────────────────┘
                 │
                 ▼ HTTPS (metrics)
         ┌───────────────┐
         │  Wakestack    │
         │  Dashboard    │
         └───────────────┘

What the Agent Collects

Agent-Based vs Agentless Monitoring

Agentless Monitoring

Checks services from outside:

• HTTP requests to endpoints
• TCP port checks
• Ping/ICMP
• DNS resolution

Pros: No installation, works immediately Cons: No internal visibility, only sees externally exposed services

Agent-Based Monitoring

Collects data from inside:

• System resource metrics
• Process information
• Internal service health
• Custom metrics

Pros: Deep visibility, root cause analysis Cons: Requires installation, more setup

You Need Both

Together: "Your API is down because CPU is at 100%"

Wakestack's Agent-Based Approach

Wakestack includes a lightweight Go agent that provides:

1. Essential Server Metrics

• CPU usage and load
• Memory utilization
• Disk space and I/O
• Running processes

2. Nested Host Integration

Connect server metrics to uptime checks:

Production API Server
├── HTTP /api/health (uptime check)
├── CPU: 78%
├── Memory: 65%
├── Disk: 45%
└── Processes: node, nginx

When uptime monitoring triggers, you see server state at the same moment.

3. Lightweight Footprint

4. Simple Installation

curl -sSL https://wakestack.co.uk/install.sh | bash

One command. Runs as systemd service. Auto-updates.

When You Need Agent-Based Monitoring

1. You Manage Your Own Servers

If you have SSH access to servers (VPS, bare metal, cloud VMs), you can install an agent and should.

• Digital Ocean droplets ✓
• AWS EC2 instances ✓
• Linode servers ✓
• Self-hosted hardware ✓

2. You Need to Know WHY Things Break

Uptime monitoring alerts tell you something is wrong. Agent monitoring tells you:

• Was it CPU exhaustion?
• Memory running out?
• Disk full?
• Process crashed?

3. You Want Proactive Alerts

Agent monitoring catches problems before they cause outages:

• Disk at 85% → Warning before 100%
• Memory growing → Alert before OOM
• CPU trending up → Scale before saturation

4. You Run Multiple Services Per Server

If one server hosts multiple applications:

• Web server
• Background workers
• Cache
• Database

Agent monitoring shows which service is consuming resources.

When You Don't Need Agent-Based Monitoring

1. You Use Serverless/PaaS

If you run on:

• Vercel
• Netlify
• Heroku
• AWS Lambda
• Cloudflare Workers

There's no server to monitor. Use uptime monitoring for endpoints.

2. You Already Have Infrastructure Monitoring

If you're using Datadog, New Relic, or Prometheus for infrastructure, you don't need another agent. Use Wakestack for uptime and status pages.

3. You Only Need External Checks

If you genuinely only care "is it up?" without caring why, agentless monitoring suffices.

Comparing Agent-Based Solutions

Wakestack Agent

Architecture: Single Go binary Metrics: CPU, memory, disk, processes Integration: With uptime monitoring and status pages Price: Included in all plans

Best for: Teams wanting server + uptime monitoring together

Datadog Agent

Architecture: Python-based, modular Metrics: Comprehensive (500+ integrations) Integration: Full observability platform Price: $15+/host/month

Best for: Enterprise teams needing deep infrastructure visibility

Prometheus Node Exporter

Architecture: Go binary, Prometheus ecosystem Metrics: Extensive system metrics Integration: Requires Prometheus + Grafana setup Price: Free (self-hosted)

Best for: Teams already running Prometheus

Netdata Agent

Architecture: C-based, highly optimized Metrics: Thousands of metrics, 1-second resolution Integration: Cloud or self-hosted Price: Free (basic), paid cloud features

Best for: Deep metrics with beautiful visualizations

Setting Up Wakestack's Agent

Step 1: Get Your Host Token

In Wakestack dashboard:

1. Navigate to Hosts
2. Click "Add Host"
3. Copy your unique host token

Step 2: Install the Agent

curl -sSL https://wakestack.co.uk/install.sh | bash

The script:

• Downloads the latest agent
• Creates systemd service
• Configures with your token
• Starts collection

Step 3: Verify Installation

Check agent status:

systemctl status wakestack-agent

View recent logs:

journalctl -u wakestack-agent -f

Step 4: Set Alert Thresholds

In Wakestack dashboard:

CPU warning: > 80%
CPU critical: > 95%
Memory warning: > 85%
Memory critical: > 95%
Disk warning: > 80%
Disk critical: > 90%

Step 5: Connect to Uptime Monitors

Link your server to its endpoints:

• API health check → This server
• Website → This server

Now you see correlated data.

Agent Security Considerations

What the Agent Does

• Reads system files (read-only)
• Sends metrics over HTTPS
• Auto-updates from official source

What the Agent Doesn't Do

• Make changes to your system
• Execute remote commands
• Access application data
• Store credentials

Best Practices

1. Use official installation - Don't download agents from unofficial sources
2. Keep updated - Auto-updates include security patches
3. Review permissions - Agent runs as non-root when possible
4. Monitor agent itself - Alert if agent stops reporting

Troubleshooting

Agent Not Reporting

Check if running:

systemctl status wakestack-agent

Check network:

curl -I https://api.wakestack.co.uk/health

High Agent Resource Usage

This shouldn't happen. If it does:

1. Check agent version (update if old)
2. Check for log spam
3. Contact support

Metrics Look Wrong

Verify manually:

free -h        # Memory
df -h          # Disk
top            # CPU/processes

Compare with dashboard values.

Try Wakestack Agent-Based Monitoring

Get infrastructure visibility alongside uptime monitoring.

• Server agent included free
• Uptime monitoring included
• Status pages included
• No credit card required

Start Monitoring →

Related Resources

• Server Monitoring: Complete Guide
• Uptime Monitoring: Complete Guide
• Uptime Monitoring for Servers