How to Deploy Wazuh SIEM Security Monitoring on Ubuntu Linux VPS

Introduction to Wazuh Architecture

Wazuh is a comprehensive, open-source SIEM and XDR solution. The architecture comprises the Wazuh Server (for log analysis, intrusion detection, and active response), the Wazuh Indexer (a highly scalable full-text search engine based on OpenSearch), and the Wazuh Dashboard (Kibana-derived UI). Agents deployed on endpoints stream telemetry back to the server.

Modern system administration requires robust, scalable open-source tooling. Deploying Wazuh fundamentally shifts control away from expensive SaaS platforms and places it directly into the hands of the infrastructure engineer. This comprehensive tutorial will rigorously guide you through deploying Wazuh on an Ubuntu Linux Virtual Private Server, ensuring a production-ready, hardened environment.

Hardware Sizing & Prerequisite Checklist

Before initializing the deployment, your infrastructure must meet strict baseline requirements. Failing to provision adequate hardware will invariably result in critical service degradation or kernel out-of-memory (OOM) panics.

• Compute & Memory: Minimum 4 vCPU cores, 8GB RAM (16GB recommended for production with Indexer), 50GB NVMe SSD (log storage scales aggressively), and a clean Ubuntu 22.04 LTS instance.
• Operating System: A freshly installed Ubuntu Linux VPS (preferably 22.04 LTS or 24.04 LTS).
• Networking: A statically assigned IPv4 address and a registered domain name (e.g., yourdomain.com) with A records pointing to your server’s IP.
• Software Dependencies: `curl`, `wget`, `git`, and `ufw` firewall pre-installed.

Step-by-Step Linux Installation & Configuration

The contemporary standard for application deployment relies heavily on containerization. Utilizing Docker and Docker Compose ensures complete environmental parity and isolates the application layer from the underlying host OS.

Execute the following commands to install the Docker engine directly from the official repository:

sudo apt update && sudo apt upgrade -y
sudo apt install ca-certificates curl gnupg lsb-release -y
sudo mkdir -m 0755 -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt update
sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y
sudo systemctl enable docker --now

Wazuh is incredibly complex; the recommended method is using the Wazuh Installation Assistant script. Alternatively, deploy the Docker Compose stack above. You must configure system variables via `sysctl -w vm.max_map_count=262144` before starting, as the OpenSearch-based indexer strictly requires it to initialize.

Production Docker Compose Configuration

version: '3.8'
services:
  wazuh.manager:
    image: wazuh/wazuh-manager:4.7.0
    hostname: wazuh.manager
    ports:
      - "1514:1514"
      - "1515:1515"
      - "55000:55000"
    environment:
      - INDEXER_URL=https://wazuh.indexer:9200
      - INDEXER_USERNAME=admin
      - INDEXER_PASSWORD=SecretPassword
      - WAZUH_API_USER=wazuh-wui
      - WAZUH_API_PASSWORD=wazuh-wui-password
    volumes:
      - ossec-api-configuration:/var/ossec/api/configuration
      - ossec-etc:/var/ossec/etc
      - ossec-logs:/var/ossec/logs
    networks:
      - wazuh-net
  wazuh.indexer:
    image: wazuh/wazuh-indexer:4.7.0
    environment:
      - "OPENSEARCH_INITIAL_ADMIN_PASSWORD=SecretPassword"
      - "bootstrap.memory_lock=true"
    ulimits:
      memlock:
        soft: -1
        hard: -1
    volumes:
      - indexer-data:/var/lib/wazuh-indexer
    networks:
      - wazuh-net
networks:
  wazuh-net:
volumes:
  ossec-api-configuration:
  ossec-etc:
  ossec-logs:
  indexer-data:

Nginx Reverse Proxy & TLS Configuration

Directly exposing application ports to the public internet violates zero-trust architectural principles. An Nginx reverse proxy handles load balancing, HTTP header manipulation, and essential TLS termination.

sudo apt install nginx -y

Create the following configuration block at `/etc/nginx/sites-available/wazuh`:

server {
    listen 80;
    server_name siem.yourdomain.com;
    
    location / {
        proxy_pass https://127.0.0.1:5601; # Dashboard port
        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;
    }
}

Performance Tuning & Benchmark Comparison Table

Log retention will rapidly consume disk space. Define aggressive Index Lifecycle Management (ILM) policies to delete or archive cold indices after 30 days. Tune the JVM heap for both the Indexer and Manager to utilize no more than 50% of the available system RAM.

To demonstrate the efficacy of this deployment, we compare the self-hosted metrics against standard industry baselines:

| Node | CPU Requirement | RAM Requirement |
|---|---|---|
| Indexer (Single Node) | 2 Cores | 4GB - 8GB |
| Manager | 2 Cores | 2GB - 4GB |
| Dashboard | 1 Core | 1GB - 2GB |

Security Hardening: UFW, SSL, and Permissions

Agents communicate over port 1514 (TCP/UDP). Ensure your UFW firewall explicitly whitelists the IPs of your endpoints, or use TLS encryption. Rotate the OpenSearch internal admin passwords immediately after initial deployment.

Deploy the Uncomplicated Firewall (UFW) to enforce a strict default-deny policy, explicitly allowing only essential traffic protocols:

sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow 22/tcp
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw enable

Secure the endpoint with Let’s Encrypt TLS certificates:

sudo apt install certbot python3-certbot-nginx -y
sudo certbot --nginx -d yourdomain.com --agree-tos --redirect -m [email protected]

Real-World Troubleshooting FAQ

Why is the Wazuh Indexer container constantly restarting?

This is almost universally caused by failing to set `vm.max_map_count=262144` on the host OS, or allocating insufficient JVM heap space resulting in Out-Of-Memory crashes.

How do I add custom decoders and rules?

Navigate to the Wazuh Dashboard, under Management > Rules. Add your custom XML configurations there. You must restart the Wazuh Manager for rule changes to take effect.

Can Wazuh monitor Office 365 or AWS infrastructure?

Yes, Wazuh includes native Cloud Security Posture Management (CSPM) modules. You can configure the `ossec.conf` file to pull logs directly from AWS CloudTrail or the Office 365 Management API.

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Advanced Kernel & Network Optimization (Deep Dive)

Beyond the fundamental installation, extracting maximum performance from your Linux VPS requires delving into kernel-level TCP/IP stack tuning and file descriptor management. Applications that handle substantial concurrent connections, webhooks, or asynchronous database transactions inevitably encounter bottlenecks at the operating system layer if left at default configurations.

The Linux kernel’s default parameters prioritize broad compatibility over peak throughput. To optimize your deployment, you must adjust the `sysctl.conf` configurations. The `net.core.somaxconn` parameter dictates the maximum number of queued connections allowed on a single socket. Increasing this mitigates dropped SYN packets during burst traffic. Similarly, adjusting the `net.ipv4.tcp_max_syn_backlog` ensures the kernel memory buffers can accommodate massive simultaneous handshakes.

sudo sysctl -w net.core.somaxconn=65535
sudo sysctl -w net.ipv4.tcp_max_syn_backlog=16384
sudo sysctl -w net.ipv4.tcp_keepalive_time=300

Furthermore, standard file descriptor limits (`ulimit`) are often severely constrained for database and search operations. Modern applications maintain numerous persistent database connections and log file streams. Modifying `/etc/security/limits.conf` to increase the soft and hard limits for the `root` and `docker` system users dramatically enhances stability, preventing the infamous ‘Too many open files’ fatal exception during high-load scenarios.

Finally, disk I/O performance directly dictates the responsiveness of persistent volumes mapping to Postgres, Redis, or application cache layers. Switching the I/O scheduler to `mq-deadline` or `none` on NVMe storage bypasses unnecessary rotational latency optimizations, feeding data directly to the hardware controller. By combining aggressive network queuing, expansive file handler limits, and streamlined disk I/O protocols, your deployment is guaranteed to achieve enterprise-grade resilience and sub-millisecond local network response times.

In addition to kernel tuning, implementing a comprehensive monitoring strategy is paramount. Prometheus and Grafana should be deployed alongside your primary applications to scrape metrics endpoint data. Monitoring CPU wait times (iowait), memory paging rates, and Docker container CPU throttling provides actionable intelligence before system failure occurs. For logging, the ELK stack (Elasticsearch, Logstash, Kibana) or a lightweight alternative like Promtail and Loki can ingest Nginx access logs and application stderr/stdout streams, enabling rapid anomaly detection and forensic analysis during security incidents.

By rigorously applying these foundational Linux engineering principles, your self-hosted infrastructure will routinely outperform managed SaaS equivalents while maintaining absolute data sovereignty and minimizing recurring operational expenses.