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Install and deploy

Fractal Server is the core ingredient of the Fractal framework, which includes several other Fractal components (e.g. a web client) and also relies on external resources being available (e.g. a PostgreSQL database and a SLURM cluster).

This page describes the basic procedure to setup and maintain a local fractal-server deployment, which is useful for testing and development, but a full-fledged deployment involves many more aspects. Some examples of deployment setups are available as container-based demos at https://github.com/fractal-analytics-platform/fractal-containers/tree/main/examples.

Prerequisites

The following will assume that:

  • You are using a Python version greater or equal than 3.11

  • You are working within an isolated Python environment, for example a virtual environment created through venv as in 

    python3 -m venv venv
./venv/bin/activate

  • You have configured the required environment variables (see configuration page).

  • If you choose to declare the environment variables using the .fractal_server.env file, that file must be placed in the current working directory;

  • You have access to a dedicated PostgreSQL database (see the database page).

  • A few common UNIX tools are available, including du, find, cut, cat, wc, bash, ls, tar, ssh and unzip.

Install

Fractal Server is hosted on PyPI, and can be installed with pip: 

pip install fractal-server

Fractal Server is also available as a Conda package, but the PyPI version is the recommended one.

For details on how to install Fractal Server in a development environment see the Development page.

How to deploy

Installing fractal-server will automatically install fractalctl, its companion command-line utility that provides the basic commands for deploying Fractal Server.

Set up database schemas

Use the command 

fractalctl set-db
to apply the schema migrations to the database. This command uses the configuration variables described in DatabaseSettings - notably including the database name POSTGRES_DB.

Note: the corresponding PostgreSQL database must already exist, since it won't be created by fractalctl set-db. You can often create it directly through createdb.

Initialize database data

With the command 

fractalctl init-db-data
you can initialize several relevant database tables. Its behaviors depends on the environment variables and command-line arguments (see the fractalctl init-db-data documentation), and it can optionally

  • create the default user group (if FRACTAL_DEFAULT_GROUP_NAME=All);
  • create the first admin user, by providing the --admin-* flags;
  • create the first resource/profile pair and associate users to them, providing --resource and --profile.

Start fractal-server

Use the command 

fractalctl start
to start the server using Uvicorn.

To verify that the server is up, you can use the /api/alive/ endpoint - as in 

curl http://localhost:8000/api/alive/
{"alive":true,"version":"2.17.0"}

Upgrade fractal-server

The high-level procedure for upgrading fractal-server on an existing instance is as follows:

  • Stop the running fractal-server process.
  • Create a backup dump of the current database data (see database page).
  • Review the CHANGELOG, and check whether this version upgrade requires any special procedure.
  • Upgrade fractal-server (e.g. as in pip install fractal-server==1.2.3).
  • Update the database schemas (as in fractalctl set-db).
  • If the CHANGELOG requires it, run the data-migration command (fractalctl update-db-data). Depending on the specific upgrade, this may require additional actions or information.
  • Restart the fractal-server process.