Runbook: Prometheus Node Exporter Installation

Overview

Install and configure Prometheus Node Exporter on Linux to expose system metrics (CPU, memory, disk, network) to Prometheus.

• OS: Ubuntu / Debian
• Default Port: 9100/TCP
• Metrics Endpoint: http://SERVER_IP:9100/metrics
• Service Manager: systemd

Choose one installation method. Do not install both on the same server.

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Method 1: Install via APT

1. Update Packages

sudo apt update

2. Check Available Version

apt-cache policy prometheus-node-exporter

3. Install Node Exporter

sudo apt install -y prometheus-node-exporter

4. Enable and Start Service

sudo systemctl enable --now prometheus-node-exporter

5. Verify Installation

sudo systemctl status prometheus-node-exporter
sudo ss -tulnp | grep 9100
curl -fsS http://localhost:9100/metrics | head

6. Check Logs

sudo journalctl -u prometheus-node-exporter -n 50 --no-pager

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Method 2: Manual Installation (GitHub Binary)

1. Set Version and Architecture

VERSION="1.9.1"
ARCH="amd64"
cd /tmp

2. Download Binary

wget "https://github.com/prometheus/node_exporter/releases/download/v${VERSION}/node_exporter-${VERSION}.linux-${ARCH}.tar.gz"

Use the appropriate architecture (amd64 or arm64). Verify the download checksum against the official release before installing. Do not bypass TLS certificate validation.

3. Extract and Install

tar -xzf "node_exporter-${VERSION}.linux-${ARCH}.tar.gz"

sudo install -o root -g root -m 0755 \
  "node_exporter-${VERSION}.linux-${ARCH}/node_exporter" \
  /usr/local/bin/node_exporter

4. Create Service User

sudo useradd --system --no-create-home \
  --shell /usr/sbin/nologin node_exporter

5. Create systemd Service

sudo tee /etc/systemd/system/node_exporter.service > /dev/null <<'EOF'
[Unit]
Description=Prometheus Node Exporter
Wants=network-online.target
After=network-online.target

[Service]
Type=simple
User=node_exporter
Group=node_exporter
ExecStart=/usr/local/bin/node_exporter
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

6. Enable and Start Service

sudo systemctl daemon-reload
sudo systemctl enable --now node_exporter

7. Verify Installation

/usr/local/bin/node_exporter --version
sudo systemctl status node_exporter
sudo ss -tulnp | grep 9100
curl -fsS http://localhost:9100/metrics | head

8. Check Logs

sudo journalctl -u node_exporter -n 50 --no-pager

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Prometheus Configuration

1. Edit Prometheus Configuration

On the Prometheus server:

sudo nano /etc/prometheus/prometheus.yml

2. Add Scrape Target

Add the following job under the existing scrape_configs section:

  - job_name: "node_exporter"
    scrape_interval: 15s
    static_configs:
      - targets:
          - "NODE_EXPORTER_IP:9100"

Replace NODE_EXPORTER_IP with the target server's IP address.

3. Validate and Restart Prometheus

promtool check config /etc/prometheus/prometheus.yml
sudo systemctl restart prometheus

Commands assume a systemd-based Prometheus installation.

4. Verify Target

Open:

http://PROMETHEUS_IP:9090/targets

Expected status: UP

Verify using PromQL:

up{job="node_exporter"}

Expected result: 1

---

Firewall Configuration

Allow inbound traffic on port 9100 from the Prometheus server only.

For UFW:

sudo ufw allow from PROMETHEUS_IP to any port 9100 proto tcp

Replace PROMETHEUS_IP with the actual Prometheus server IP.

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Service Management

Action	APT Installation	Manual Installation
Start	systemctl start prometheus-node-exporter	systemctl start node_exporter
Stop	systemctl stop prometheus-node-exporter	systemctl stop node_exporter
Restart	systemctl restart prometheus-node-exporter	systemctl restart node_exporter
Status	systemctl status prometheus-node-exporter	systemctl status node_exporter
Logs	journalctl -u prometheus-node-exporter -f	journalctl -u node_exporter -f

Use sudo for service management commands.

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Troubleshooting

Issue	Check / Resolution
Service not running	sudo journalctl -u node_exporter -n 50
Port 9100 unavailable	sudo ss -tulnp \| grep 9100
Prometheus target DOWN	Verify IP, firewall, service status and connectivity
Metrics endpoint unreachable	curl -v http://NODE_EXPORTER_IP:9100/metrics
GitHub SSL certificate error	Check proxy, TLS inspection and CA trust; do not disable certificate verification
Port already in use	Check for an existing Node Exporter instance

---

Rollback / Uninstall

APT Installation

sudo systemctl disable --now prometheus-node-exporter
sudo apt purge -y prometheus-node-exporter

Manual Installation

sudo systemctl disable --now node_exporter
sudo rm -f /etc/systemd/system/node_exporter.service
sudo systemctl daemon-reload
sudo rm -f /usr/local/bin/node_exporter
sudo userdel node_exporter

Remove the corresponding scrape target from Prometheus configuration and reload or restart Prometheus.

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Acceptance Criteria

• [ ] Node Exporter service is active (running).
• [ ] Port 9100/TCP is listening.
• [ ] /metrics endpoint returns HTTP 200.
• [ ] Prometheus target status is UP.
• [ ] up{job="node_exporter"} returns 1.
• [ ] Firewall permits access only from authorized monitoring hosts.