Install bare metal prometheus node_exporter on Redhat distros.

node_exporter_install.sh

#!/bin/bash

# Exit immediately if a command exits with a non-zero status.
set -e

# Variables
NODE_EXPORTER_VERSION="1.8.2"
NODE_EXPORTER_USER="node_exporter"
NODE_EXPORTER_BINARY="/usr/local/bin/node_exporter"
NODE_EXPORTER_SERVICE="/etc/systemd/system/node_exporter.service"

# Determine the correct binary based on system architecture
ARCH=$(uname -m)
if [[ "$ARCH" == "x86_64" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-amd64.tar.gz"
elif [[ "$ARCH" == "aarch64" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-arm64.tar.gz"
elif [[ "$ARCH" == "armv5" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-armv5.tar.gz"
elif [[ "$ARCH" == "armv6" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-armv6.tar.gz"
elif [[ "$ARCH" == "armv7" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-armv7.tar.gz"
elif [[ "$ARCH" == "mips" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-mips.tar.gz"
elif [[ "$ARCH" == "mips64" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-mips64.tar.gz"
elif [[ "$ARCH" == "i386" || "$ARCH" == "i686" ]]; then
    DOWNLOAD_URL="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-386.tar.gz"
else
    echo "Unsupported architecture: $ARCH"
    exit 1
fi

# Verify that the URL exists
if ! curl --output /dev/null --silent --head --fail "$DOWNLOAD_URL"; then
    echo "Download URL does not exist: $DOWNLOAD_URL"
    exit 1
fi

# Ensure necessary utilities are installed
if ! command -v wget &>/dev/null || ! command -v tar &>/dev/null; then
    echo "Installing required utilities: wget, tar"
    sudo yum install -y wget tar
fi

# Create a dedicated user if not exists
if ! id -u "$NODE_EXPORTER_USER" >/dev/null 2>&1; then
    echo "Creating user: $NODE_EXPORTER_USER"
    sudo useradd -r -s /bin/false "$NODE_EXPORTER_USER"
fi

# Remove existing Node Exporter binary if reinstalling
if [ -f "$NODE_EXPORTER_BINARY" ]; then
    echo "Removing existing Node Exporter binary."
    sudo rm -f "$NODE_EXPORTER_BINARY"
fi

# Download and install Node Exporter
echo "Downloading and installing Node Exporter v$NODE_EXPORTER_VERSION"
wget -q "$DOWNLOAD_URL" -O /tmp/node_exporter.tar.gz
if [ ! -s /tmp/node_exporter.tar.gz ]; then
    echo "Download failed or file is empty. Exiting."
    exit 1
fi
tar -xzf /tmp/node_exporter.tar.gz -C /tmp
if [ ! -f "/tmp/node_exporter-${NODE_EXPORTER_VERSION}.linux-arm64/node_exporter" ]; then
    echo "Extracted binary not found. Exiting."
    exit 1
fi
if [ ! -d "/usr/local/bin" ]; then
    echo "Destination directory /usr/local/bin does not exist. Creating it."
    sudo mkdir -p /usr/local/bin
fi
sudo mv "/tmp/node_exporter-${NODE_EXPORTER_VERSION}.linux-arm64/node_exporter" "$NODE_EXPORTER_BINARY"
sudo chmod +x "$NODE_EXPORTER_BINARY"
rm -rf "/tmp/node_exporter-${NODE_EXPORTER_VERSION}.linux-arm64" /tmp/node_exporter.tar.gz

# Remove existing Node Exporter service file if reinstalling
if [ -f "$NODE_EXPORTER_SERVICE" ]; then
    echo "Removing existing Node Exporter service file."
    sudo rm -f "$NODE_EXPORTER_SERVICE"
fi

# Create systemd service file
echo "Creating systemd service file for Node Exporter"
cat <<EOF | sudo tee "$NODE_EXPORTER_SERVICE"
[Unit]
Description=Prometheus Node Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=$NODE_EXPORTER_USER
Group=$NODE_EXPORTER_USER
Type=simple
ExecStart=$NODE_EXPORTER_BINARY
RuntimeDirectory=node_exporter
StateDirectory=node_exporter
CacheDirectory=node_exporter

[Install]
WantedBy=multi-user.target
EOF

sudo systemctl daemon-reload

# Check if systemctl is available
if ! command -v systemctl &>/dev/null; then
    echo "Systemctl is not available on this system. Exiting."
    exit 1
fi

# Validate systemd service file before restarting
sudo systemd-analyze verify "$NODE_EXPORTER_SERVICE" || true

# Enable and start Node Exporter
sudo systemctl enable node_exporter
sudo systemctl restart node_exporter

# Verify that the service reloads without errors
if sudo systemctl is-active --quiet node_exporter; then
    echo "Node Exporter service restarted successfully."
else
    echo "Node Exporter service failed to restart. Check logs with: sudo journalctl -u node_exporter"
    exit 1
fi

# Verify the installation
if sudo systemctl is-active --quiet node_exporter; then
    echo "Node Exporter is running successfully."
    echo "Metrics available at: http://$(hostname -I | awk '{print $1}'):9100/metrics"
else
    echo "Node Exporter failed to start. Check the logs with: sudo journalctl -u node_exporter"
    exit 1
fi