tahoe-lafs/README

Welcome to the AllMyData "tahoe" project. This project implements a
distributed fault-tolerant storage mesh.

The basic idea is that the data in this storage mesh is spread over all
participating nodes, using an algorithm that can recover the data even if a
majority of the nodes are no longer available.

The main application code is in the 'allmydata' package, under src/allmydata/
. There is also a patched version of PyCrypto (adding a faster CTR-mode) in
src/Crypto/ which gets installed to the 'allmydata.Crypto' package (since the
API is different than the normal Crypto package). It also includes Zooko's
PyFEC library, a fast python wrapper around the Rizzo 'fec' C library,
installed to the 'zfec' package and located in src/zfec/ .

DEPENDENCIES:

 * Python 2.4 or newer (tested against both 2.4 and 2.5) (language)
  http://python.org/

 * Twisted (tested against both 2.4 and 2.5) (network and operating system)
  http://twistedmatrix.com/

  You need the following subpackages (which are are included in the default
  Twisted distribution):

   * core (the standard Twisted package)
   * web, trial, conch

  Twisted requires zope.interface, a copy of which is included in the Twisted
  distribution.

 * Foolscap (0.1.2 or newer) (remote objects)
  http://twistedmatrix.com/trac/wiki/FoolsCap

  Note: since the Foolscap wire protocol is not yet compatible from one
  release to the next, make sure all of your nodes are using the same version
  of Foolscap

 * Nevow (probably 0.9.0 or later) (web presentation language)
  http://divmod.org/trac/wiki/DivmodNevow

 * PyOpenSSL (0.6 or later) (secure transport layer)
  http://pyopenssl.sourceforge.net

 * a C compiler (language)

 * GNU make (build tool)

 * to build the debian packages you will need all the usual debian-packaging
   tools, which means the 'build-essential' metapackage and all of the
   packages listed as "Build-Depends" in DIST/debian/control for your
   distribution. You will also want the 'fakeroot' package to allow the
   top-level 'make deb-DIST' targets work.


 * setuptools (build and distribution tool)
  http://peak.telecommunity.com/DevCenter/EasyInstall#installation-instructions

BUILDING:

 Just type 'make'. This works on Windows too, provided that you have the
 dependencies mentioned above (either a normal cygwin build or a mingw-style
 native build is supported by the makefile -- the cygwin build is the
 default).

 If the desired version of 'python' is not already on your PATH, then type
 'make PYTHON=/path/to/your/preferred/python'.

 'make test' runs the unit test suite.

INSTALLING:

 If you're running on a debian system, use 'make deb-dapper' or 'make
 deb-sid' to construct a debian package named 'allmydata-tahoe', which you
 can then install.

 If not, you'll need to run three separate install steps, one for each of the
 three subpackages (allmydata, allmydata.Crypto, and zfec). You may wish to
 use a different version of 'python' for these steps, or provide a --prefix
 or --root argument for the install.

  cd src/zfec && python setup.py install && cd ../..

  cd src/Crypto && python setup.py install && cd ../..

  # the allmydata subpackage's setup.py script is in the root directory
  python setup.py install

 To test that all the modules got installed properly, start a python
 interpreter and import modules as follows:

  % python
  Python 2.4.4 (#2, Jan 13 2007, 17:50:26)
  [GCC 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import allmydata.Crypto
  >>> import allmydata.interfaces
  >>> import fec
  >>>

 To run from a source tree (without installing first), type 'make', which
 will put all the necessary libraries into a local directory named
 instdir/lib/pythonN.N/site-packages/ , which you can then add to your
 PYTHONPATH .


RUNNING:

 If you installed one of the debian packages constructed by "make deb-*" then
 it creates an 'allmydata-tahoe' executable, usually in /usr/bin . If you
 didn't install a package you can find allmydata-tahoe in bin/ . This tool is
 used to create, start, and stop nodes. Each node lives in a separate base
 directory, inside of which you can add files to configure and control the
 node. Nodes also read and write files within that directory.

 A mesh consists of a single central 'introducer' node and a large number of
 'client' nodes. If you are joining an existing mesh, the introducer node
 will already be running, and you'll just need to create a client node. If
 you're creating a brand new mesh, you'll need to create both an introducer
 and a client (and then invite other people to create their own client nodes
 and join your mesh).

 The introducer node is constructed by running 'allmydata-tahoe
 create-introducer --basedir $HERE'. Once constructed, you can start the
 introducer by running 'allmydata-tahoe start --basedir $HERE' (or, if you
 are already in the introducer's base directory, just type 'allmydata-tahoe
 start'). Inside that base directory, there will be a pair of files
 'introducer.furl' and 'vdrive.furl'. Make a copy of these, as they'll be
 needed on the client nodes.

 To construct a client node, pick a new working directory for it, then run
 'allmydata-tahoe create-client --basedir $HERE'. Copy the two .furl files
 from the introducer into this new directory, then run 'allmydata-tahoe start
 --basedir $HERE'. After that, the client node should be off and running. The
 first thing it will do is connect to the introducer and introduce itself to
 all other nodes on the mesh. You can follow its progress by looking at the
 $HERE/twistd.log file.

 To actually use the client, enable the web interface by writing a port
 number (like "8080") into a file named $HERE/webport and then restarting the
 node with 'allmydata-tahoe restart --basedir $HERE'. This will prompt the
 client node to run a webserver on the desired port, through which you can
 view, upload, download, and delete files.