Python

The cPanel Setup Python App tool registers a Python WSGI app under your account, builds a virtualenv, and hands the running process to Phusion Passenger. CloudLinux ships Python interpreters as alt-python packages. Each app picks its own version, and the virtualenv lives separate from the system Python.

Available versions

Available versions vary by host. Typical rotation:

Python 3.11. Active.
Python 3.10. Maintained.
Python 3.9. Older, still common for legacy apps.

Older alt-python (3.7, 3.8, 2.7) may be available for compatibility. Avoid Python 2 for anything new.

Set up an app

Open Setup Python App

From cPanel home, scroll to Software and click Setup Python App.

Setup Python App tool icon — cPanel home → Software → Setup Python App

Click Create Application

On an empty account, you land on a list page with a + Create Application button.

Fill in the form

Python version: pick from the dropdown.
Application root: directory under your home, e.g. myapp. Created if it doesn’t exist.
Application URL: domain dropdown plus optional path. Use / for the root or /api for a sub-path.
Application startup file: defaults to passenger_wsgi.py. Leave it as that unless you have a reason.
Application Entry point: dotted path plus callable, format module:callable. For Django: <project>.wsgi:application. For Flask: <module>:app.
Passenger log file: optional. Useful for catching boot errors.

Save

Click Create. Passenger starts the app in the background.

Manage an app

Button	What it does
Run Pip Install	Reads `requirements.txt` and installs into the per-app virtualenv.
Stop App	Halts Passenger for this app. The URL returns 503.
Restart	Equivalent to `touch tmp/restart.txt`. Reloads the running app.
Edit	Reopens the form. Saving overwrites the `.htaccess`.
Destroy	Removes Passenger registration and the per-app virtualenv.

The Configuration files field accepts paths like requirements.txt (relative to the application root). The Environment variables editor sits below the buttons.

The Passenger contract

Passenger expects a WSGI callable named application. Your passenger_wsgi.py either defines it directly or imports it from your app. For Flask:

passenger_wsgi.py

from myapp import app as application

For Django:

passenger_wsgi.py

import os
import sys

sys.path.insert(0, '/home/<user>/myapp')
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myapp.settings')

from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()

Your code does not run a development server. No app.run(), no manage.py runserver.

Calling app.run() (Flask) or runserver (Django) inside a Passenger-managed app makes Passenger see no application and return a 500 with passenger_wsgi.py did not provide an "application" callable. Remove the call.

ASGI apps

Native ASGI (FastAPI, Starlette, Channels) needs a WSGI shim. The common bridge is asgiref.WsgiToAsgi reversed, but Passenger’s WSGI mode does not handle WebSockets or HTTP/2 streaming over ASGI. For a sync FastAPI subset, wrap with a2wsgi:

passenger_wsgi.py

from a2wsgi import ASGIMiddleware
from main import app as asgi_app

application = ASGIMiddleware(asgi_app)

For real WebSockets, run Daphne or Uvicorn outside the Selector.

Reference: where things live

What	Path
Activated env script	`~/virtualenv/<app-root>/<version>/bin/activate`
Installed packages	`~/virtualenv/<app-root>/<version>/lib/...`
Restart trigger	`~/<app-root>/tmp/restart.txt`
Passenger config	`~/<app-root>/.htaccess` (Selector-managed)
Boot log (if configured)	path you set in Passenger log file

From SSH, activate manually:

source ~/virtualenv/myapp/3.11/bin/activate && cd ~/myapp
pip install -r requirements.txt

Common issues

500: 'did not provide an application callable'

passenger_wsgi.py doesn’t expose a top-level name application. Either rename your callable to application, or alias it: application = app.

ImportError on a package that pip just installed

The package was installed against the system Python, not the per-app virtualenv. Run Pip Install from the cPanel UI, or activate the env in SSH first: source ~/virtualenv/<app>/<ver>/bin/activate.

Static files 404 on Django

Passenger only serves the WSGI app. Run manage.py collectstatic and serve /static/ directly from Apache. Add to .htaccess:

Alias /static/ /home/<user>/myapp/static/
<Directory "/home/<user>/myapp/static">
  Require all granted
</Directory>

`pip install pandas` (or numpy) runs out of memory

PMEM is ~1 GB. Heavy compiled wheels can OOM. Use prebuilt wheels (the default for pandas / numpy on linux x86_64), avoid --no-binary, and consider installing one package at a time.

Boot times out on a Django app

Default Passenger startup timeout is 60 seconds. Long migrations or heavy INSTALLED_APPS initialization can exceed it. Bump the timeout in .htaccess:

PassengerStartTimeout 120

Recipes

Deploy Django

Django app, virtualenv, static files.

Deploy Flask

Flask service via passenger_wsgi.py.

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Open a ticket

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Live chat

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Sources

cPanel Control Panels

Virtual Containers

Available versions

Set up an app

Manage an app

The Passenger contract

ASGI apps

Reference: where things live

Common issues

Recipes

Deploy Django

Deploy Flask

Need a hand?

Open a ticket

Live chat

​Available versions

​Set up an app

​Manage an app

​The Passenger contract

​ASGI apps

​Reference: where things live

​Common issues

​Recipes

Deploy Django

Deploy Flask

​Need a hand?

Open a ticket

Live chat

Available versions

Set up an app

Manage an app

The Passenger contract

ASGI apps

Reference: where things live

Common issues

Recipes

Need a hand?