Deploy Prometheus on RamNode VPS

Prerequisites & VPS Selection

Small Setup

• 1GB RAM
• 1 vCPU
• 1-5 targets

Production

• 4GB+ RAM
• 4 vCPU
• 50+ targets

💡 Tip: Storage needs grow with retention period. Plan ~2GB per day for 100 active time series with 15s scrape interval.

Install Prometheus

Update your system and create a dedicated user for Prometheus:

Update system and create user

# Update system packages
sudo apt update && sudo apt upgrade -y

# Create prometheus user (no login shell)
sudo useradd --no-create-home --shell /bin/false prometheus

# Create directories
sudo mkdir -p /etc/prometheus
sudo mkdir -p /var/lib/prometheus

# Set ownership
sudo chown prometheus:prometheus /etc/prometheus
sudo chown prometheus:prometheus /var/lib/prometheus

Download and install the latest Prometheus release:

Download and install Prometheus

# Download Prometheus (check prometheus.io for latest version)
cd /tmp
PROM_VERSION="2.48.0"
wget https://github.com/prometheus/prometheus/releases/download/v${PROM_VERSION}/prometheus-${PROM_VERSION}.linux-amd64.tar.gz

# Extract the archive
tar xvfz prometheus-${PROM_VERSION}.linux-amd64.tar.gz
cd prometheus-${PROM_VERSION}.linux-amd64

# Copy binaries
sudo cp prometheus /usr/local/bin/
sudo cp promtool /usr/local/bin/

# Set ownership
sudo chown prometheus:prometheus /usr/local/bin/prometheus
sudo chown prometheus:prometheus /usr/local/bin/promtool

# Copy console libraries
sudo cp -r consoles /etc/prometheus
sudo cp -r console_libraries /etc/prometheus
sudo chown -R prometheus:prometheus /etc/prometheus/consoles
sudo chown -R prometheus:prometheus /etc/prometheus/console_libraries

# Verify installation
prometheus --version

Configure Prometheus

Create the main Prometheus configuration file:

Create configuration file

sudo nano /etc/prometheus/prometheus.yml

/etc/prometheus/prometheus.yml

global:
  scrape_interval: 15s
  evaluation_interval: 15s
  external_labels:
    monitor: 'prometheus-server'

# Alertmanager configuration (optional)
alerting:
  alertmanagers:
    - static_configs:
        - targets:
          # - alertmanager:9093

# Load rules once and periodically evaluate them
rule_files:
  # - "alert_rules.yml"

# Scrape configurations
scrape_configs:
  # Monitor Prometheus itself
  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

  # Monitor the local machine with Node Exporter
  - job_name: 'node'
    static_configs:
      - targets: ['localhost:9100']

Set permissions and validate

sudo chown prometheus:prometheus /etc/prometheus/prometheus.yml

# Validate the configuration
promtool check config /etc/prometheus/prometheus.yml

Install Node Exporter

Node Exporter collects hardware and OS metrics from your server:

Download and install Node Exporter

# Create node_exporter user
sudo useradd --no-create-home --shell /bin/false node_exporter

# Download Node Exporter
cd /tmp
NODE_VERSION="1.7.0"
wget https://github.com/prometheus/node_exporter/releases/download/v${NODE_VERSION}/node_exporter-${NODE_VERSION}.linux-amd64.tar.gz

# Extract and install
tar xvfz node_exporter-${NODE_VERSION}.linux-amd64.tar.gz
sudo cp node_exporter-${NODE_VERSION}.linux-amd64/node_exporter /usr/local/bin/
sudo chown node_exporter:node_exporter /usr/local/bin/node_exporter

Create Node Exporter systemd service

sudo nano /etc/systemd/system/node_exporter.service

/etc/systemd/system/node_exporter.service

[Unit]
Description=Node Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=node_exporter
Group=node_exporter
Type=simple
ExecStart=/usr/local/bin/node_exporter \
    --collector.systemd \
    --collector.processes

[Install]
WantedBy=multi-user.target

Start Node Exporter

sudo systemctl daemon-reload
sudo systemctl start node_exporter
sudo systemctl enable node_exporter
sudo systemctl status node_exporter

Create Prometheus Systemd Service

Create Prometheus service file

sudo nano /etc/systemd/system/prometheus.service

/etc/systemd/system/prometheus.service

[Unit]
Description=Prometheus Monitoring
Wants=network-online.target
After=network-online.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/usr/local/bin/prometheus \
    --config.file=/etc/prometheus/prometheus.yml \
    --storage.tsdb.path=/var/lib/prometheus/ \
    --web.console.templates=/etc/prometheus/consoles \
    --web.console.libraries=/etc/prometheus/console_libraries \
    --web.listen-address=0.0.0.0:9090 \
    --storage.tsdb.retention.time=30d \
    --web.enable-lifecycle

ExecReload=/bin/kill -HUP $MAINPID
Restart=on-failure

[Install]
WantedBy=multi-user.target

Start Prometheus

sudo systemctl daemon-reload
sudo systemctl start prometheus
sudo systemctl enable prometheus
sudo systemctl status prometheus

✅ Success! Prometheus is now accessible at http://YOUR_SERVER_IP:9090

Configure Nginx Reverse Proxy

Install Nginx and create password file

# Install Nginx and apache2-utils for htpasswd
sudo apt install nginx apache2-utils -y

# Create password file (replace 'admin' with your username)
sudo htpasswd -c /etc/nginx/.htpasswd admin

# Create Nginx configuration
sudo nano /etc/nginx/sites-available/prometheus

/etc/nginx/sites-available/prometheus

server {
    listen 80;
    server_name prometheus.yourdomain.com;

    location / {
        auth_basic "Prometheus";
        auth_basic_user_file /etc/nginx/.htpasswd;
        
        proxy_pass http://localhost:9090;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Enable site

sudo ln -s /etc/nginx/sites-available/prometheus /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl restart nginx

SSL Certificate with Let's Encrypt

Install Certbot and obtain SSL

# Install Certbot
sudo apt install certbot python3-certbot-nginx -y

# Obtain SSL certificate
sudo certbot --nginx -d prometheus.yourdomain.com

# Verify auto-renewal
sudo certbot renew --dry-run

Configure Alerting Rules

Create alert rules for common monitoring scenarios:

Create alert rules file

sudo nano /etc/prometheus/alert_rules.yml

/etc/prometheus/alert_rules.yml

groups:
  - name: node_alerts
    rules:
      # High CPU usage alert
      - alert: HighCPUUsage
        expr: 100 - (avg by(instance) (rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "High CPU usage on {{ $labels.instance }}"
          description: "CPU usage is above 80% for more than 5 minutes."

      # High memory usage alert
      - alert: HighMemoryUsage
        expr: (1 - (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes)) * 100 > 85
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "High memory usage on {{ $labels.instance }}"

      # Disk space running low
      - alert: DiskSpaceLow
        expr: (node_filesystem_avail_bytes{mountpoint="/"} / node_filesystem_size_bytes{mountpoint="/"}) * 100 < 15
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: "Low disk space on {{ $labels.instance }}"

      # Instance down alert
      - alert: InstanceDown
        expr: up == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Instance {{ $labels.instance }} down"

Enable rules and reload

# Edit prometheus.yml and uncomment: rule_files: ["alert_rules.yml"]
sudo nano /etc/prometheus/prometheus.yml

# Set ownership
sudo chown prometheus:prometheus /etc/prometheus/alert_rules.yml

# Validate rules
promtool check rules /etc/prometheus/alert_rules.yml

# Reload Prometheus configuration
curl -X POST http://localhost:9090/-/reload

Monitoring Examples

Monitor Multiple Servers

Multiple Node Exporter targets

# In prometheus.yml, update the node job:
scrape_configs:
  - job_name: 'node'
    static_configs:
      - targets:
          - 'server1.example.com:9100'
          - 'server2.example.com:9100'
          - '192.168.1.10:9100'
        labels:
          env: 'production'
      - targets:
          - 'staging1.example.com:9100'
        labels:
          env: 'staging'

Monitor Docker Containers

cAdvisor for Docker monitoring

# Run cAdvisor as a container
docker run -d \
  --name=cadvisor \
  --privileged \
  -p 8080:8080 \
  -v /:/rootfs:ro \
  -v /var/run:/var/run:ro \
  -v /sys:/sys:ro \
  -v /var/lib/docker/:/var/lib/docker:ro \
  gcr.io/cadvisor/cadvisor:latest

Add to prometheus.yml

  - job_name: 'cadvisor'
    static_configs:
      - targets: ['localhost:8080']

Monitor HTTP Endpoints (Blackbox)

Blackbox Exporter for endpoint monitoring

# Download and install blackbox_exporter
wget https://github.com/prometheus/blackbox_exporter/releases/download/v0.24.0/blackbox_exporter-0.24.0.linux-amd64.tar.gz
tar xvfz blackbox_exporter-0.24.0.linux-amd64.tar.gz
sudo cp blackbox_exporter-0.24.0.linux-amd64/blackbox_exporter /usr/local/bin/
sudo cp blackbox_exporter-0.24.0.linux-amd64/blackbox.yml /etc/prometheus/

# Start blackbox exporter
blackbox_exporter --config.file=/etc/prometheus/blackbox.yml &

HTTP endpoint monitoring config

  - job_name: 'blackbox-http'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
          - https://example.com
          - https://api.example.com/health
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: localhost:9115

Monitor MySQL/MariaDB

MySQL Exporter setup

# Create MySQL user for exporter
mysql -u root -p -e "
CREATE USER 'exporter'@'localhost' IDENTIFIED BY 'your_password';
GRANT PROCESS, REPLICATION CLIENT, SELECT ON *.* TO 'exporter'@'localhost';
FLUSH PRIVILEGES;"

# Create credentials file
cat > /etc/.mysqld_exporter.cnf << EOF
[client]
user=exporter
password=your_password
EOF

# Download and run mysqld_exporter
wget https://github.com/prometheus/mysqld_exporter/releases/download/v0.15.1/mysqld_exporter-0.15.1.linux-amd64.tar.gz
tar xvfz mysqld_exporter-0.15.1.linux-amd64.tar.gz
./mysqld_exporter --config.my-cnf=/etc/.mysqld_exporter.cnf &

Add MySQL to prometheus.yml

  - job_name: 'mysql'
    static_configs:
      - targets: ['localhost:9104']

Grafana Integration

Install Grafana

# Install Grafana
sudo apt-get install -y apt-transport-https software-properties-common wget
wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
echo "deb https://packages.grafana.com/oss/deb stable main" | sudo tee /etc/apt/sources.list.d/grafana.list
sudo apt-get update
sudo apt-get install grafana -y

# Start Grafana
sudo systemctl start grafana-server
sudo systemctl enable grafana-server

Add Prometheus as a Data Source:

Open Grafana at http://YOUR_IP:3000 (default: admin/admin)
Go to Configuration → Data Sources → Add data source
Select Prometheus
Set URL to http://localhost:9090
Click Save & Test

📊 Recommended Dashboards:

• Node Exporter Full (ID: 1860) - Server metrics
• Docker Dashboard (ID: 893) - Container monitoring
• MySQL Overview (ID: 7362) - Database metrics

Maintenance & Useful Queries

Storage Management

Storage management commands

# Check Prometheus storage usage
du -sh /var/lib/prometheus/

# Create snapshot via API
curl -X POST http://localhost:9090/api/v1/admin/tsdb/snapshot

# Copy to backup location
cp -r /var/lib/prometheus/snapshots/* /backup/prometheus/

Useful PromQL Queries

Common PromQL queries

# CPU usage percentage
100 - (avg by(instance) (rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100)

# Memory usage percentage
(1 - (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes)) * 100

# Disk usage percentage
(1 - (node_filesystem_avail_bytes{mountpoint="/"} / node_filesystem_size_bytes{mountpoint="/"})) * 100

# Network traffic (bytes/sec)
rate(node_network_receive_bytes_total[5m])

Troubleshooting

Prometheus won't start

Debug Prometheus startup

# Check logs
sudo journalctl -u prometheus -f

# Validate configuration
promtool check config /etc/prometheus/prometheus.yml

# Check file permissions
ls -la /etc/prometheus/
ls -la /var/lib/prometheus/

Target shows as DOWN

Debug target connectivity

# Check if exporter is running
curl localhost:9100/metrics

# Check firewall rules
sudo ufw status

# Test connectivity from Prometheus server
curl http://target_ip:9100/metrics

Reload without restart

Hot reload configuration

# Send SIGHUP signal
sudo kill -HUP $(pidof prometheus)

# Or use the reload endpoint
curl -X POST http://localhost:9090/-/reload

Congratulations!

You've successfully deployed Prometheus monitoring on your RamNode VPS. Your metrics collection system is now operational.

Setup Grafana Dashboards Explore More Guides

Security Considerations

• Never expose Prometheus directly to the internet - Always use a reverse proxy with authentication
• Use firewall rules - Restrict port 9090 and 9100 to trusted IPs only
• Enable HTTPS - Use SSL certificates for all external access
• Secure Node Exporters - Use basic auth or keep them on private networks
• Regular updates - Keep Prometheus and exporters updated for security patches

Self-Hosted Prometheus

📋 Guide Contents