Mastering Internal Networking in Coolify: Connecting n8n, Flowise, and OpenSearch Like a Pro

If you run a self-hosted stack on Coolify (v4), you likely have powerful AI tools like n8n, Flowise, LangFlow, and OpenSearch running side-by-side. But there is a catch: out of the box, Coolify assigns them long, random container names like n8n-cs0gs0kogswgsgwk....

If you try to connect n8n to Flowise using that name, your connection breaks the moment you redeploy.

In this post, I will document how to set up stable internal hostnames, how to handle HTTPS-only services (like OpenSearch), and how to verify your connections using wget or curl.

Part 1: Setting Stable Hostnames

We want to move from fragile, random names to clean, permanent internal URLs. There are two ways to do this in Coolify.

Method A: For “Docker Image” Deployments

Use this for apps installed via the Coolify UI (e.g., Docling).

1. Go to the app Configuration.
2. Scroll to the Network section.
3. In the Network Aliases field, type your simple name (e.g., docling).
4. Click Save and Redeploy.

Result: Reachable at http://docling:5001.

Method B: For “Docker Compose” Deployments

Use this for Stacks or apps where you have the “Edit Compose File” button (e.g., n8n, LangFlow).

1. Click Edit Compose File.
2. Find the service definition (under services:).
3. Add the hostname property:

services:
  n8n:
    image: docker.n8n.io/n8nio/n8n:latest
    hostname: n8n  # <--- ADD THIS
    ...

4. Click Save & Restart.

Result: Reachable at http://n8n:5678.

Part 2: Verifying Connections

Don’t guess—test! Go to the Terminal of the app you are connecting from.

Docker containers are often minimal. Some have wget, some have curl. Here is how to use both.

Option A: Using wget (Most Common)

If curl is missing, use wget.

• -q: Quiet mode.
• -O-: Print output to screen (Standard Output).

wget -qO- http://flowise:3000

Option B: Using curl (Cleanest Output)

If installed, curl is excellent for debugging headers.

• -v: Verbose (shows the handshake).
• -I: Head only (shows status without downloading the page).

# Full check (shows handshake + content)
curl -v http://flowise:3000

# Status check only (cleaner)
curl -I http://flowise:3000

Part 3: The “HTTPS” Curveball (OpenSearch)

Most internal traffic is HTTP. However, services like OpenSearch force HTTPS even internally. If you use HTTP, the connection will be reset.

How to test securely (ignoring certificates)

Since OpenSearch uses a self-signed certificate, you must tell your tool to ignore verification.

With wget:

wget --no-check-certificate -qO- https://opensearch:9200

With curl:

curl -k -v https://opensearch:9200

(The -k flag stands for “insecure” / skip certificate check).

Part 4: Troubleshooting Guide

Interpret your terminal results to find the root cause:

Summary Cheat Sheet

Pro Tip: When configuring nodes in n8n or LangFlow to talk to OpenSearch, always look for the “Ignore SSL” or “Allow Insecure” toggle and turn it ON.