Langflow 1.6.9 (Ubuntu 22.04) AMI Administrator Guide

1. Quick Start Information

Usage instructions:

Connection Methods:

Access the instance via SSH using the ubuntu user. Use sudo to run commands requiring root privileges. To switch to the root user, use sudo su - root.

Install Information:

OS: Ubuntu 22.04 LTS
Langflow version: 1.6.9
Langflow Install Directory: /usr/local/langflow

Langflow Service Management:

To start Langflow Service: sudo systemctl start langflow
To stop Langflow Service: sudo systemctl stop langflow
To status Langflow Service: sudo systemctl status langflow

Accessing Langflow:

Visit https://YOUR_IP to start using Langflow.

Web username and password:

View via the command: sudo cat /usr/local/langflow/readme

Firewall Configuration:

Please allow SSH port 22 and Langflow port 443.
For security, it is recommended to limit access to trusted IPs only.

2. Overview

Welcome to this Langflow 1.6.9 AMI. This image is based on Ubuntu 22.04 LTS and has been pre-configured as a secure, auto-starting production environment.

This guide not only explains how to use this AMI but also details its internal configuration.

Core Features: Langflow 1.6.9, Full-featured (CPU Torch, EasyOCR), HTTPS, Password Authentication, systemd auto-start.
Target Audience: System administrators and advanced users who need to deploy or manage Langflow instances.

3. First Launch & Access (Mandatory)

Step 1: Configure Security Group (Firewall)

In your cloud provider's console (e.g., AWS EC2), add inbound rules to the security group for this instance to allow:

TCP Port 443 (HTTPS): Required for accessing the Langflow Web interface (Mandatory).
TCP Port 22 (SSH): (Optional) Allows logging into the server for management.

Step 2: Access the Langflow Instance

Get your instance's public IP address.
Open a brand new browser "Incognito Window".
In the address bar, type https:// and your IP address (do not add a port number): https://[Your_Public_IP]

Step 3: Handle the SSL Security Warning

You will see a full-screen security warning ("NET::ERR_CERT_AUTHORITY_INVALID").
This is normal, because this AMI uses a self-signed certificate to ensure traffic is encrypted.
Please click "Advanced" -> "Proceed to [IP Address] (unsafe)".

You will now see the Langflow login page. Please enter the default credentials (see Section 5).

4. Architecture & Detailed Configuration

All configurations in this AMI follow Linux production environment standards.

Service Architecture: [Public] -> Nginx (Port 443, SSL) -> Langflow (127.0.0.1:7860)
Service User: All applications run as the non-root user ubuntu.
Application Directory: /usr/local/langflow

4.1. Langflow Application & Virtual Environment

Path

/usr/local/langflow

Includes Files

.venv/: The Python virtual environment, containing langflow, torch, easyocr, and all other libraries.
.env: The configuration file storing all passwords and secret keys.

Configuration (How-To-Create)

This directory and environment were configured via the following steps (as root and ubuntu users):

# (As root) 1. Create directory and set permissions
sudo mkdir -p /usr/local/langflow
sudo chown ubuntu:ubuntu /usr/local/langflow

# (As root) 2. Switch to ubuntu user
sudo -u ubuntu -i

# --- (As ubuntu) 3. Install uv ---
curl -Lfs https://astral.sh/uv/install.sh | sh
source /home/ubuntu/.bashrc

# --- (As ubuntu) 4. Enter new directory and create environment ---
cd /usr/local/langflow
uv venv

# --- (As ubuntu) 5. Critical 3-step installation ---
# 5.1. Pre-install CPU version of torch
uv pip install torch --index-url https://download.pytorch.org/whl/cpu

# 5.2. Install Langflow 1.6.9 core
uv pip install "langflow==1.6.9" -U

# 5.3. Manually install "all" dependencies (easyocr, unstructured)
uv pip install easyocr unstructured

# --- (As ubuntu) 6. Exit ---
exit

4.2. Langflow Credentials (.env file)

Path

/usr/local/langflow/.env

File Content

(This is the environment variable file loaded by langflow.service)

# --- Force enable authentication ---
LANGFLOW_AUTO_LOGIN=False

# --- Your Superuser ---
# (Recommended to run "openssl rand -base64 18" to generate a strong password)
LANGFLOW_SUPERUSER=YOUR_ADMIN_NAME
LANGFLOW_SUPERUSER_PASSWORD=YOUR_PASSWORD

# --- Your Security Key ---
# (Must be set! Run "openssl rand -hex 32" to generate your own)
LANGFLOW_SECRET_KEY=Your_Own_64_Char_Secret_Key_Here

# --- Recommended Security Settings ---
LANGFLOW_NEW_USER_IS_ACTIVE=False
LANGFLOW_ENABLE_SUPERUSER_CLI=False

Configuration (How-To-Create)

# (As ubuntu user)
cd /usr/local/langflow
vi .env
# (Paste the content above)
chmod 600 .env

4.3. Langflow Auto-start Service (systemd)

Path

/etc/systemd/system/langflow.service

File Content

(This file defines how langflow runs as a system service)

[Unit]
Description=Langflow Server
After=network.target

[Service]
# Run as ubuntu user
User=ubuntu
Group=ubuntu

# Load all passwords and configurations from .env file
EnvironmentFile=/usr/local/langflow/.env

# (Critical) Set the correct working directory
WorkingDirectory=/usr/local/langflow/

# (Critical) uv is in ubuntu's home, langflow is in .venv (auto), listening locally
ExecStart=/home/ubuntu/.local/bin/uv run langflow run --host 127.0.0.1 --port 7860

# Auto-restart policy
Restart=always
RestartSec=5s

StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

Configuration (How-To-Create)

# (As root)
sudo vi /etc/systemd/system/langflow.service
# (Paste the content above)
sudo systemctl daemon-reload
sudo systemctl enable langflow

4.4. Nginx Reverse Proxy (SSL)

Path

/etc/nginx/sites-enabled/langflow

File Content

(This file is a symbolic link to /etc/nginx/sites-available/langflow)

# --- HTTP Redirect Block (Port 80 -> 443) ---
server {
    listen 80;
    listen [::]:80;

    # Listen on all IPs/Domains
    server_name _;

    # Force redirect all HTTP traffic to HTTPS
    return 301 https://$host$request_uri;
}

# --- Main Langflow Server Block (Port 443) ---
server {
    listen 443 ssl;
    listen [::]:443 ssl;

    server_name _;

    # SSL Configuration
    ssl_certificate /etc/nginx/ssl/langflow.crt;
    ssl_certificate_key /etc/nginx/ssl/langflow.key;
    ssl_protocols TLSv1.2 TLSv1.3;

    location / {
        # Forward traffic to local Langflow service
        proxy_pass http://127.0.0.1:7860;

        # Standard Proxy Headers
        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;

        # WebSocket Support (Required for Langflow chat)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}

Configuration (How-To-Create)

# (As root) 1. Create self-signed certificate (10-year validity)
sudo mkdir -p /etc/nginx/ssl
sudo openssl req -x509 -nodes -days 3650 -newkey rsa:2048 \
 -keyout /etc/nginx/ssl/langflow.key \
 -out /etc/nginx/ssl/langflow.crt \
 -subj "/C=US/ST/N/A/L/N/A/O=LangflowAMI/CN=localhost"

# (As root) 2. Create Nginx config file
sudo vi /etc/nginx/sites-available/langflow
# (Paste the Nginx config content above)

# (As root) 3. Activate configuration (create symbolic link)
sudo ln -s /etc/nginx/sites-available/langflow /etc/nginx/sites-enabled/

# (As root) 4. (Recommended) Remove default configuration
sudo rm /etc/nginx/sites-enabled/default

# (As root) 5. Restart Nginx
sudo systemctl restart nginx

5. Credentials & Security (Quick Reference)

View the default administrator and password via the command sudo cat /usr/local/langflow/readme

How to Change: Log in via SSH, edit the /usr/local/langflow/.env file, and then run sudo systemctl restart langflow.

6. Service Management (Quick Reference)

Check Langflow Status: sudo systemctl status langflow
Restart Langflow: sudo systemctl restart langflow
Check Langflow Logs: sudo journalctl -u langflow -f
Check Nginx Status: sudo systemctl status nginx
Restart Nginx: sudo systemctl restart nginx

7. Troubleshooting

Problem: Cannot connect to the server.
- Solution: Check your cloud provider's Security Group to ensure TCP Port 443 is open to your IP.
Problem: I see a "400 Bad Request".
- Solution: Ensure you are typing https:// in your browser's address bar, not http://. Use an incognito window.

1. Quick Start Information​

2. Overview​

3. First Launch & Access (Mandatory)​

Step 1: Configure Security Group (Firewall)​

Step 2: Access the Langflow Instance​

Step 3: Handle the SSL Security Warning​

Step 4: Login​

4. Architecture & Detailed Configuration​

4.1. Langflow Application & Virtual Environment​

Path​

Includes Files​

Configuration (How-To-Create)​

4.2. Langflow Credentials (.env file)​

Path​

File Content​

Configuration (How-To-Create)​

4.3. Langflow Auto-start Service (systemd)​

Path​

File Content​

Configuration (How-To-Create)​

4.4. Nginx Reverse Proxy (SSL)​

Path​

File Content​

Configuration (How-To-Create)​

5. Credentials & Security (Quick Reference)​

6. Service Management (Quick Reference)​

7. Troubleshooting​

1. Quick Start Information

2. Overview

3. First Launch & Access (Mandatory)

Step 1: Configure Security Group (Firewall)

Step 2: Access the Langflow Instance

Step 3: Handle the SSL Security Warning

Step 4: Login

4. Architecture & Detailed Configuration

4.1. Langflow Application & Virtual Environment

Path

Includes Files

Configuration (How-To-Create)

4.2. Langflow Credentials (.env file)

Path

File Content

Configuration (How-To-Create)

4.3. Langflow Auto-start Service (systemd)

Path

File Content

Configuration (How-To-Create)

4.4. Nginx Reverse Proxy (SSL)

Path

File Content

Configuration (How-To-Create)

5. Credentials & Security (Quick Reference)

6. Service Management (Quick Reference)

7. Troubleshooting