Open source AI stack on VPS: Ollama, Open WebUI and n8n

Why assemble this stack rather than using each tool separately

What the stack delivers concretely

• Private inference — Mistral 7B, Llama 3, Phi-3 or any GGUF model runs locally; no prompt ever leaves your VPS.
• Multi-user chat interface — Open WebUI exposes separate accounts, isolated histories and an endpoint compatible with Ollama's OpenAI API.
• Automation without plugins — n8n consumes http://ollama:11434 via its native HTTP Request node; the n8n.io/integrations documentation confirms no additional dependency is required.
• Predictable cost — a single monthly VPS price replaces per-token fees from a cloud API; 8 GB of RAM is sufficient for Mistral 7B, Open WebUI and n8n in queue mode.
• Version control — each tool updates independently; no forced migration imposed by a SaaS vendor.
• Full portability — a docker compose down && docker compose up is enough to migrate the stack to a more powerful VPS; Docker volumes carry all state.
• Verified official Docker images — docker.io/ollama/ollama, ghcr.io/open-webui/open-webui and docker.io/n8nio/n8n are maintained by each respective project.
• Secure internal mesh — the three services communicate over a private Docker network; no LLM port is exposed publicly.

Prerequisites: RAM, CPU and domain

Deploy the stack with Docker Compose

1. 01

   Prepare the VPS

   Connect via SSH and install Docker if not already done: curl -fsSL https://get.docker.com | sh. Verify that Docker Compose is available with docker compose version. Create a working directory: mkdir -p /opt/ia-stack && cd /opt/ia-stack.

2. 02

   Write the docker-compose.yml

   Declare the three services in a single docker-compose.yml file on a shared internal network:

   services:
     ollama:
       image: docker.io/ollama/ollama
       volumes:
         - ollama_data:/root/.ollama
       networks:
         - ia
       restart: unless-stopped
   
     open-webui:
       image: ghcr.io/open-webui/open-webui:main
       environment:
         - OLLAMA_BASE_URL=http://ollama:11434
       volumes:
         - webui_data:/app/backend/data
       networks:
         - ia
       restart: unless-stopped
   
     n8n:
       image: docker.io/n8nio/n8n
       environment:
         - N8N_BASIC_AUTH_ACTIVE=true
         - N8N_BASIC_AUTH_USER=admin
         - N8N_BASIC_AUTH_PASSWORD=change-this-password
         - WEBHOOK_URL=https://n8n.your-domain.com
       volumes:
         - n8n_data:/home/node/.n8n
       networks:
         - ia
       restart: unless-stopped
   
   networks:
     ia:
       driver: bridge
   
   volumes:
     ollama_data:
     webui_data:
     n8n_data:

   No port is exposed on the host: the reverse proxy will be the only entry point.

3. 03

   Start the containers

   Launch the stack: docker compose up -d. Verify that all three containers are running with docker compose ps. To view the logs of a service: docker compose logs -f ollama. At this point, no service is accessible from the outside.

4. 04

   Download a model into Ollama

   Enter the Ollama container to fetch a model: docker compose exec ollama ollama pull mistral. The command downloads and quantizes the model into the ollama_data volume. Check the list of available models with docker compose exec ollama ollama list. Open WebUI will automatically detect the models present in Ollama at startup.

5. 05

   Configure the reverse proxy

   Install Caddy or Nginx on the host to expose Open WebUI and n8n over HTTPS. With Caddy, two blocks suffice in your Caddyfile:

   chat.your-domain.com {
     reverse_proxy open-webui:8080
   }
   
   n8n.your-domain.com {
     reverse_proxy n8n:5678
   }

   Caddy obtains and renews Let's Encrypt certificates automatically. Ollama is not exposed directly — it remains accessible only from other containers via the ia network.

6. 06

   Create the Open WebUI administrator account

   Open https://chat.your-domain.com in your browser. On first access, Open WebUI prompts you to create an administrator account (email + password). This account is local to your instance — no data transits to an external service. You can then create additional accounts from the administration interface and select a default model from those listed by Ollama.

7. 07

   Connect n8n to the Ollama API

   In n8n (https://n8n.your-domain.com), create a workflow and add an HTTP Request node. Configure it as follows: method POST, URL http://ollama:11434/api/generate, JSON body {"model": "mistral", "prompt": "{{ $json.prompt }}", "stream": false}. n8n communicates with Ollama via the internal Docker network — no API key, no external quota. This node is native to n8n and documented on n8n.io/integrations.

Securing the stack before exposing it

VPS profiles for the stack

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Use case: automating a summary pipeline with n8n