Deploying Applications

This guide walks through deploying real-world applications with pyinfra, from basic web applications to complex multi-tier architectures. You’ll learn how to structure deployments, handle dependencies, and create reusable deployment patterns.

Deployment Structure

A well-organized deployment typically includes:

myapp-deploy/
├── inventory/
│   ├── production.py
│   ├── staging.py
│   └── development.py
├── templates/
│   ├── nginx.conf.j2
│   ├── app.service.j2
│   └── env.j2
├── files/
│   ├── ssh_keys/
│   └── ssl/
├── deploy.py
└── tasks/
    ├── web.py
    ├── database.py
    └── monitoring.py

Simple Web Application

Let’s start with deploying a Python Flask application.

Create inventory

inventory.py

targets = [
    ("web-01.example.com", {
        "ssh_user": "deploy",
        "ssh_key": "~/.ssh/deploy_key",
    }),
]

# Application configuration
app_name = "myapp"
app_repo = "https://github.com/example/myapp.git"
app_branch = "main"
app_port = 8000
app_workers = 4
domain = "myapp.example.com"

Create nginx template

templates/nginx.conf.j2

server {
    listen 80;
    server_name {{ domain }};

    location / {
        proxy_pass http://127.0.0.1:{{ app_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;
    }

    location /static {
        alias /opt/{{ app_name }}/static;
    }
}

Create systemd service template

templates/app.service.j2

[Unit]
Description={{ app_name }} Application
After=network.target

[Service]
Type=simple
User={{ app_user }}
WorkingDirectory=/opt/{{ app_name }}
Environment="PATH=/opt/{{ app_name }}/venv/bin"
ExecStart=/opt/{{ app_name }}/venv/bin/gunicorn -w {{ app_workers }} -b 127.0.0.1:{{ app_port }} app:app
Restart=always

[Install]
WantedBy=multi-user.target

Create deploy file

deploy.py

from pyinfra import host
from pyinfra.operations import apt, files, git, server, systemd

# Install system dependencies
apt.packages(
    name="Install system packages",
    packages=[
        "python3",
        "python3-pip",
        "python3-venv",
        "nginx",
        "git",
    ],
    update=True,
    _sudo=True,
)

# Create application user
server.user(
    name="Create app user",
    user=host.data.app_name,
    home=f"/opt/{host.data.app_name}",
    shell="/bin/bash",
    system=True,
    _sudo=True,
)

# Create application directory
files.directory(
    name="Create app directory",
    path=f"/opt/{host.data.app_name}",
    user=host.data.app_name,
    group=host.data.app_name,
    mode="755",
    _sudo=True,
)

# Clone application repository
git.repo(
    name="Clone application",
    src=host.data.app_repo,
    dest=f"/opt/{host.data.app_name}",
    branch=host.data.app_branch,
    pull=True,
    user=host.data.app_name,
    _sudo=True,
)

# Create virtual environment
server.shell(
    name="Create Python virtual environment",
    commands=[
        f"cd /opt/{host.data.app_name}",
        "python3 -m venv venv",
    ],
    _sudo=True,
    _sudo_user=host.data.app_name,
)

# Install Python dependencies
server.shell(
    name="Install Python dependencies",
    commands=[
        f"cd /opt/{host.data.app_name}",
        "venv/bin/pip install -r requirements.txt",
    ],
    _sudo=True,
    _sudo_user=host.data.app_name,
)

# Configure systemd service
files.template(
    name="Create systemd service",
    src="templates/app.service.j2",
    dest=f"/etc/systemd/system/{host.data.app_name}.service",
    app_name=host.data.app_name,
    app_user=host.data.app_name,
    app_workers=host.data.app_workers,
    app_port=host.data.app_port,
    _sudo=True,
)

# Reload systemd
systemd.daemon_reload(
    name="Reload systemd",
    _sudo=True,
)

# Start and enable application service
server.service(
    name="Start application service",
    service=host.data.app_name,
    running=True,
    enabled=True,
    restarted=True,
    _sudo=True,
)

# Configure nginx
nginx_config = files.template(
    name="Configure nginx",
    src="templates/nginx.conf.j2",
    dest=f"/etc/nginx/sites-available/{host.data.app_name}",
    domain=host.data.domain,
    app_name=host.data.app_name,
    app_port=host.data.app_port,
    _sudo=True,
)

# Enable nginx site
files.link(
    name="Enable nginx site",
    path=f"/etc/nginx/sites-enabled/{host.data.app_name}",
    target=f"/etc/nginx/sites-available/{host.data.app_name}",
    _sudo=True,
)

# Remove default nginx site
files.file(
    name="Remove default nginx site",
    path="/etc/nginx/sites-enabled/default",
    present=False,
    _sudo=True,
)

# Restart nginx if config changed
server.service(
    name="Restart nginx",
    service="nginx",
    restarted=True,
    _sudo=True,
    _if=lambda: nginx_config.did_change(),
)

Deploy

pyinfra inventory.py deploy.py

Use dry-run mode first to preview changes: pyinfra inventory.py deploy.py --dry

Multi-Tier Application

Deploy an application with separate web and database tiers:

inventory.py

# Web servers
web_servers = [
    "web-01.example.com",
    "web-02.example.com",
]

web_servers_data = {
    "app_port": 8000,
    "app_workers": 4,
    "db_host": "db-01.example.com",
}

# Database servers
db_servers = [
    ("db-01.example.com", {
        "ssh_user": "postgres",
        "is_primary": True,
    }),
]

db_servers_data = {
    "postgres_version": "14",
    "max_connections": 200,
}

# All hosts
targets = web_servers + db_servers

# Global data
app_name = "myapp"
app_repo = "https://github.com/example/myapp.git"
environment = "production"

deploy.py

from pyinfra import host
from pyinfra.operations import apt, files, git, server

# Deploy to database servers
if "db_servers" in host.groups:
    apt.packages(
        name="Install PostgreSQL",
        packages=[
            f"postgresql-{host.data.postgres_version}",
            "postgresql-contrib",
        ],
        _sudo=True,
    )
    
    files.template(
        name="Configure PostgreSQL",
        src="templates/postgresql.conf.j2",
        dest=f"/etc/postgresql/{host.data.postgres_version}/main/postgresql.conf",
        max_connections=host.data.max_connections,
        _sudo=True,
    )
    
    server.service(
        name="Restart PostgreSQL",
        service="postgresql",
        restarted=True,
        _sudo=True,
    )

# Deploy to web servers
if "web_servers" in host.groups:
    # Install dependencies
    apt.packages(
        name="Install web server packages",
        packages=["python3", "python3-pip", "nginx", "postgresql-client"],
        _sudo=True,
    )
    
    # Create app user
    server.user(
        name="Create app user",
        user=host.data.app_name,
        home=f"/opt/{host.data.app_name}",
        system=True,
        _sudo=True,
    )
    
    # Clone application
    git.repo(
        name="Clone application",
        src=host.data.app_repo,
        dest=f"/opt/{host.data.app_name}",
        branch="main",
        pull=True,
        user=host.data.app_name,
        _sudo=True,
    )
    
    # Configure application with database connection
    files.template(
        name="Configure application",
        src="templates/app_config.py.j2",
        dest=f"/opt/{host.data.app_name}/config.py",
        db_host=host.data.db_host,
        app_port=host.data.app_port,
        environment=host.data.environment,
        user=host.data.app_name,
        _sudo=True,
    )
    
    # Install dependencies and start service
    server.shell(
        name="Install Python dependencies",
        commands=[
            f"cd /opt/{host.data.app_name}",
            "pip3 install -r requirements.txt",
        ],
        _sudo=True,
        _sudo_user=host.data.app_name,
    )

Reusable Deploy Functions

Create modular, reusable deployment components:

tasks/web.py

from pyinfra import host
from pyinfra.api import deploy
from pyinfra.operations import apt, files, git, server

@deploy("Setup web server")
def setup_web_server():
    """Install and configure nginx web server"""
    
    apt.packages(
        name="Install nginx",
        packages=["nginx"],
        _sudo=True,
    )
    
    files.template(
        name="Configure nginx",
        src="templates/nginx.conf.j2",
        dest="/etc/nginx/nginx.conf",
        workers=host.data.get("nginx_workers", 4),
        _sudo=True,
    )
    
    server.service(
        name="Ensure nginx is running",
        service="nginx",
        running=True,
        enabled=True,
        _sudo=True,
    )

@deploy("Deploy Python application")
def deploy_python_app(app_name, repo_url, branch="main"):
    """Deploy a Python application"""
    
    # Create user
    server.user(
        name=f"Create {app_name} user",
        user=app_name,
        home=f"/opt/{app_name}",
        system=True,
        _sudo=True,
    )
    
    # Clone repo
    git.repo(
        name=f"Clone {app_name}",
        src=repo_url,
        dest=f"/opt/{app_name}",
        branch=branch,
        pull=True,
        user=app_name,
        _sudo=True,
    )
    
    # Create venv and install deps
    server.shell(
        name="Setup Python environment",
        commands=[
            f"cd /opt/{app_name}",
            "python3 -m venv venv",
            "venv/bin/pip install -r requirements.txt",
        ],
        _sudo=True,
        _sudo_user=app_name,
    )

Use in main deploy:

deploy.py

from pyinfra import host
from tasks.web import setup_web_server, deploy_python_app

if "web_servers" in host.groups:
    setup_web_server()
    deploy_python_app(
        app_name=host.data.app_name,
        repo_url=host.data.app_repo,
        branch=host.data.app_branch,
    )

Handling Secrets

Never commit secrets to version control. Use environment variables or external secret management.

Using Environment Variables

inventory.py

import os

targets = ["web-01.example.com"]

# Load secrets from environment
database_password = os.environ.get("DATABASE_PASSWORD")
api_key = os.environ.get("API_KEY")
secret_key = os.environ.get("SECRET_KEY")

Set before deploying:

export DATABASE_PASSWORD="secret"
export API_KEY="key123"
export SECRET_KEY="random-secret"
pyinfra inventory.py deploy.py

Using .env Files

inventory.py

from pathlib import Path

# Load .env file (not committed to git)
env_file = Path(".env")
if env_file.exists():
    for line in env_file.read_text().splitlines():
        if "=" in line and not line.startswith("#"):
            key, value = line.split("=", 1)
            os.environ[key] = value

targets = ["web-01.example.com"]
database_password = os.environ.get("DATABASE_PASSWORD")

Database Migrations

Run database migrations as part of deployment:

deploy.py

from pyinfra import host
from pyinfra.operations import server

if "web_servers" in host.groups:
    # Deploy application first...
    
    # Run database migrations
    server.shell(
        name="Run database migrations",
        commands=[
            f"cd /opt/{host.data.app_name}",
            "venv/bin/python manage.py migrate",
        ],
        _sudo=True,
        _sudo_user=host.data.app_name,
    )
    
    # Collect static files
    server.shell(
        name="Collect static files",
        commands=[
            f"cd /opt/{host.data.app_name}",
            "venv/bin/python manage.py collectstatic --noinput",
        ],
        _sudo=True,
        _sudo_user=host.data.app_name,
    )

Zero-Downtime Deployments

Deploy updates without downtime:

deploy.py

from pyinfra import host
from pyinfra.operations import files, git, server

# Update code
git.repo(
    name="Pull latest code",
    src=host.data.app_repo,
    dest=f"/opt/{host.data.app_name}",
    branch=host.data.app_branch,
    pull=True,
    user=host.data.app_name,
    _sudo=True,
)

# Install any new dependencies
server.shell(
    name="Update dependencies",
    commands=[
        f"cd /opt/{host.data.app_name}",
        "venv/bin/pip install -r requirements.txt",
    ],
    _sudo=True,
    _sudo_user=host.data.app_name,
)

# Graceful reload (for gunicorn/uwsgi)
server.shell(
    name="Graceful reload",
    commands=[f"systemctl reload {host.data.app_name}"],
    _sudo=True,
)

Complete Example: Django Application

targets = [
    ("web-01.example.com", {
        "ssh_user": "deploy",
        "ssh_key": "~/.ssh/deploy_key",
    }),
]

app_name = "django_app"
app_repo = "https://github.com/example/django-app.git"
app_branch = "main"
app_port = 8000
app_workers = 4
domain = "example.com"

# Database config
db_name = "django_db"
db_user = "django_user"
db_host = "localhost"

from pyinfra import host
from pyinfra.operations import apt, files, git, postgresql, server, systemd

# Install system packages
apt.packages(
    name="Install system packages",
    packages=[
        "python3",
        "python3-pip",
        "python3-venv",
        "postgresql",
        "postgresql-contrib",
        "nginx",
        "git",
    ],
    update=True,
    _sudo=True,
)

# Create PostgreSQL database and user
postgresql.database(
    name="Create database",
    database=host.data.db_name,
    _sudo=True,
    _sudo_user="postgres",
)

postgresql.user(
    name="Create database user",
    user=host.data.db_user,
    password=host.data.db_password,
    _sudo=True,
    _sudo_user="postgres",
)

# Create app user
server.user(
    name="Create app user",
    user=host.data.app_name,
    home=f"/opt/{host.data.app_name}",
    system=True,
    _sudo=True,
)

# Clone application
git.repo(
    name="Clone application",
    src=host.data.app_repo,
    dest=f"/opt/{host.data.app_name}",
    branch=host.data.app_branch,
    pull=True,
    user=host.data.app_name,
    _sudo=True,
)

# Setup Python environment
server.shell(
    name="Create virtual environment",
    commands=[
        f"cd /opt/{host.data.app_name}",
        "python3 -m venv venv",
        "venv/bin/pip install -r requirements.txt",
    ],
    _sudo=True,
    _sudo_user=host.data.app_name,
)

# Configure Django settings
files.template(
    name="Configure Django",
    src="templates/django_settings.py.j2",
    dest=f"/opt/{host.data.app_name}/config/settings.py",
    db_name=host.data.db_name,
    db_user=host.data.db_user,
    db_password=host.data.db_password,
    db_host=host.data.db_host,
    secret_key=host.data.secret_key,
    user=host.data.app_name,
    _sudo=True,
)

# Run migrations
server.shell(
    name="Run Django migrations",
    commands=[
        f"cd /opt/{host.data.app_name}",
        "venv/bin/python manage.py migrate",
        "venv/bin/python manage.py collectstatic --noinput",
    ],
    _sudo=True,
    _sudo_user=host.data.app_name,
)

# Configure systemd service
files.template(
    name="Create systemd service",
    src="templates/gunicorn.service.j2",
    dest=f"/etc/systemd/system/{host.data.app_name}.service",
    _sudo=True,
)

systemd.daemon_reload(name="Reload systemd", _sudo=True)

server.service(
    name="Start application",
    service=host.data.app_name,
    running=True,
    enabled=True,
    restarted=True,
    _sudo=True,
)

# Configure nginx
files.template(
    name="Configure nginx",
    src="templates/nginx.conf.j2",
    dest=f"/etc/nginx/sites-available/{host.data.app_name}",
    _sudo=True,
)

files.link(
    name="Enable nginx site",
    path=f"/etc/nginx/sites-enabled/{host.data.app_name}",
    target=f"/etc/nginx/sites-available/{host.data.app_name}",
    _sudo=True,
)

server.service(
    name="Restart nginx",
    service="nginx",
    restarted=True,
    _sudo=True,
)

Best Practices

Structure your deploys - Split complex deployments into modular functions using @deploy

Test locally first - Use @local or @docker connectors to test deploys before running on production

Use dry-run mode - Always check what will change with --dry before deploying to production

Keep secrets secure - Use environment variables or secret management tools, never commit secrets

Version your infrastructure - Commit inventory and deploy files to git for version control

Next Steps

Idempotent Operations - Understand state management
Parallel Execution - Scale deployments across many hosts
Inventory and Data - Advanced inventory patterns

Get Started

Core Concepts

Guides

CLI Reference

Advanced

Deploying Applications

Deployment Structure

Simple Web Application

Multi-Tier Application

Reusable Deploy Functions

Handling Secrets

Using Environment Variables

Using .env Files

Database Migrations

Zero-Downtime Deployments

Complete Example: Django Application

Best Practices

Next Steps

​Deployment Structure

​Simple Web Application

​Multi-Tier Application

​Reusable Deploy Functions

​Handling Secrets

​Using Environment Variables

​Using .env Files

​Database Migrations

​Zero-Downtime Deployments

​Complete Example: Django Application

​Best Practices

​Next Steps

Deployment Structure

Simple Web Application

Multi-Tier Application

Reusable Deploy Functions

Handling Secrets

Using Environment Variables

Using .env Files

Database Migrations

Zero-Downtime Deployments

Complete Example: Django Application

Best Practices

Next Steps