# Installing Tahoe-LAFS

Welcome to the Tahoe-LAFS project, a secure, decentralized, fault-tolerant storage system. See Welcome to Tahoe-LAFS! for an overview of the architecture and security properties of the system.

This procedure should work on Windows, Mac, illumos (previously OpenSolaris), and too many flavors of Linux and of BSD to list.

## First: In Case Of Trouble

In some cases these instructions may fail due to peculiarities of your platform.

If the following instructions don’t Just Work without any further effort on your part, then please write to the tahoe-dev mailing list where friendly hackers will help you out.

## Pre-Packaged Versions

You may not need to build Tahoe at all.

If you are on Windows, please see Building Tahoe-LAFS on Windows for platform-specific instructions.

If you are on a Mac, you can either follow these instructions, or use the pre-packaged bundle described in OS-X Packaging. The Tahoe project hosts pre-compiled “wheels” for all dependencies, so use the `--find-links=` option described below to avoid needing a compiler.

Many Linux distributions include Tahoe-LAFS packages. Debian and Ubuntu users can `apt-get install tahoe-lafs`. See OSPackages for other platforms.

## Preliminaries

If you don’t use a pre-packaged copy of Tahoe, you can build it yourself. You’ll need Python2.7, pip, and virtualenv. On unix-like platforms, you will need a C compiler, the Python development headers, and some libraries (libffi-dev and libssl-dev).

On a modern Debian/Ubuntu-derived distribution, this command will get you everything you need:

    apt-get install build-essential python-dev libffi-dev libssl-dev libyaml-dev python-virtualenv

On OS-X, install pip and virtualenv as described below. If you want to compile the dependencies yourself (instead of using `--find-links` to take advantage of the pre-compiled ones we host), you’ll also need to install Xcode and its command-line tools.

Note that Tahoe-LAFS depends on openssl 1.1.1c or greater.

### Python 2.7

Check if you already have an adequate version of Python installed by running `python -V`. The latest version of Python v2.7 is recommended, which is 2.7.11 as of this writing. Python v2.6.x and v3 do not work. On Windows, we recommend the use of native Python v2.7, not Cygwin Python. If you don’t have one of these versions of Python installed, download and install the latest version of Python v2.7. Make sure that the path to the installation directory has no spaces in it (e.g. on Windows, do not install Python in the “Program Files” directory):

    % python --version
    Python 2.7.11

### pip

Many Python installations already include `pip`, but in case yours does not, get it with the pip install instructions:

    % pip --version
    pip 10.0.1 from ... (python 2.7)

### virtualenv

If you do not have an OS-provided copy of `virtualenv`, install it with the instructions from the virtualenv documentation:

    % virtualenv --version
    15.1.0

### C compiler and libraries

Except on OS-X, where the Tahoe project hosts pre-compiled wheels for all dependencies, you will need several C libraries installed before you can build. You will also need the Python development headers, and a C compiler (your python installation should know how to find these).

On Debian/Ubuntu-derived systems, the necessary packages are `python-dev`, `libffi-dev`, and `libssl-dev`, and can be installed with `apt-get`. On RPM-based system (like Fedora) these may be named `python-devel`, etc, instead, and cam be installed with `yum` or `rpm`.

Note that Tahoe-LAFS depends on openssl 1.1.1c or greater.

## Install the Latest Tahoe-LAFS Release

We recommend creating a fresh virtualenv for your Tahoe-LAFS install, to isolate it from any python packages that are already installed (and to isolate the rest of your system from Tahoe’s dependencies).

This example uses a virtualenv named `venv`, but you can call it anything you like. Many people prefer to keep all their virtualenvs in one place, like `~/.local/venvs/` or `~/venvs/`.

It’s usually a good idea to upgrade the virtualenv’s `pip` and `setuptools` to their latest versions, with `venv/bin/pip install -U pip setuptools`. Many operating systems have an older version of `virtualenv`, which then includes older versions of pip and setuptools. Upgrading is easy, and only affects the virtualenv: not the rest of your computer.

Then use the virtualenv’s `pip` to install the latest Tahoe-LAFS release from PyPI with `venv/bin/pip install tahoe-lafs`. After installation, run `venv/bin/tahoe --version` to confirm the install was successful:

    % virtualenv venv
    New python executable in ~/venv/bin/python2.7
    Installing setuptools, pip, wheel...done.

    % venv/bin/pip install -U pip setuptools
    Downloading/unpacking pip from https://pypi.python.org/...
    ...
    Successfully installed pip setuptools

    % venv/bin/pip install tahoe-lafs
    Collecting tahoe-lafs
    ...
    Installing collected packages: ...
    Successfully installed ...

    % venv/bin/tahoe --version
    tahoe-lafs: 1.15.0
    foolscap: ...

    %

On OS-X, instead of `pip install tahoe-lafs`, use this command to take advantage of the hosted pre-compiled wheels:

    venv/bin/pip install --find-links=https://tahoe-lafs.org/deps tahoe-lafs

### Install From a Source Tarball

You can also install directly from the source tarball URL:

    % virtualenv venv
    New python executable in ~/venv/bin/python2.7
    Installing setuptools, pip, wheel...done.

    % venv/bin/pip install https://tahoe-lafs.org/downloads/tahoe-lafs-1.15.0.tar.bz2
    Collecting https://tahoe-lafs.org/downloads/tahoe-lafs-1.15.0.tar.bz2
    ...
    Installing collected packages: ...
    Successfully installed ...

    % venv/bin/tahoe --version
    tahoe-lafs: 1.15.0
    ...

### Extras

Tahoe-LAFS provides some functionality only when explicitly requested at installation time. It does this using the “extras” feature of setuptools. You can request these extra features when running the `pip install` command like this:

    % venv/bin/pip install tahoe-lafs[tor]

This example enables support for listening and connecting using Tor. The Tahoe-LAFS documentation for specific features which require an explicit install-time step will mention the “extra” that must be requested.

### Hacking On Tahoe-LAFS

To modify the Tahoe source code, you should get a git checkout, and install with the `--editable` flag. You should also use the `[test]` extra to get the additional libraries needed to run the unit tests:

    % git clone https://github.com/tahoe-lafs/tahoe-lafs.git

    % cd tahoe-lafs

    % virtualenv venv

    % venv/bin/pip install --editable .[test]
    Obtaining file::~/tahoe-lafs
    ...
    Successfully installed ...

    % venv/bin/tahoe --version
    tahoe-lafs: 1.15.0
    ...

This way, you won’t have to re-run the `pip install` step each time you modify the source code.

## Running the `tahoe` executable

The rest of the Tahoe-LAFS documentation assumes that you can run the `tahoe` executable that you just created. You have four basic options:

- Use the full path each time (e.g. `~/venv/bin/tahoe`).
- “Activate” the virtualenv with `. venv/bin/activate`, to get a subshell with a `$PATH` that includes the `venv/bin/` directory, then you can just run `tahoe`.
- Change your `$PATH` to include the `venv/bin/` directory, so you can just run `tahoe`.
- Symlink from `~/bin/tahoe` to the `tahoe` executable. Since `~/bin` is typically in your `$PATH` (at least if it exists when you log in), this will let you just run `tahoe`.

You might also find the pipsi tool convenient: `pipsi install tahoe-lafs` will create a new virtualenv, install tahoe into it, then symlink just the executable (into `~/.local/bin/tahoe`). Then either add `~/.local/bin/` to your `$PATH`, or make one last symlink into `~/bin/tahoe`.

## Running the Self-Tests

To run the self-tests from a source tree, you’ll need `tox` installed. On a Debian/Ubuntu system, use `apt-get install tox`. You can also install it into your tahoe-specific virtualenv with `pip install tox`.

Then just run `tox`. This will create a new fresh virtualenv, install Tahoe (from the source tree, including any changes you have made) and all its dependencies (including testing-only dependencies) into the virtualenv, then run the unit tests. This ensures that the tests are repeatable and match the results of other users, unaffected by any other Python packages installed on your machine. On a modern computer this will take 5-10 minutes, and should result in a “all tests passed” mesage:

    % tox
    GLOB sdist-make: ~/tahoe-lafs/setup.py
    py27 recreate: ~/tahoe-lafs/.tox/py27
    py27 inst: ~/tahoe-lafs/.tox/dist/tahoe-lafs-1.15.0.zip
    py27 runtests: commands[0] | tahoe --version
    py27 runtests: commands[1] | trial --rterrors allmydata
    allmydata.test.test_auth
      AccountFileCheckerKeyTests
        test_authenticated ...                                           [OK]
        test_missing_signature ...                                       [OK]
     ...
    Ran 1186 tests in 423.179s

    PASSED (skips=7, expectedFailures=3, successes=1176)
    __________________________ summary ___________________________________
      py27: commands succeeded
      congratulations :)

## Common Problems

If you see an error like `fatal error: Python.h: No such file or directory` while compiling the dependencies, you need the Python development headers. If you are on a Debian or Ubuntu system, you can install them with `sudo apt-get install python-dev`. On RedHat/Fedora, install `python-devel`.

Similar errors about `openssl/crypto.h` indicate that you are missing the OpenSSL development headers (`libssl-dev`). Likewise `ffi.h` means you need `libffi-dev`.

Note that Tahoe-LAFS depends on openssl 1.1.1c or greater.

## Using Tahoe-LAFS

Now you are ready to deploy a decentralized filesystem. You will use the `tahoe` executable to create, configure, and launch your Tahoe-LAFS nodes. See How To Run Tahoe-LAFS for instructions on how to do that.