The Unified Installer is a source installation kit for installing Python, Zope, Plone and their dependencies on Unix-like platforms. It has two major components:

• The source packages for Python, Zope, Plone, a couple of system libraries and some Python libraries;
• An installation script that uses the packages to create a ready-to-run, relatively self-contained, Python/Zope/Plone install that meets the Plone community's best-practices standards.

The new Zope/Plone install will use its own copy of Python, and the Python installed by the Unified Installer will not replace your system's copy of Python.

Why the Unified Installer? Why Not System Packages/Ports?

On the Plone help lists and channel, the suggestion to "just use the Unified Installer" often draws one of two reactions:

I prefer to manage the source install myself, picking all the target directories;

There's nothing wrong with that, though if you use the Unified Installer's target directories you may find it easier to get help from the Plone community. Also, note that the Unified Installer for Plone 3 makes it a bit easier to pick your own target directories than did previous versions.

If you still choose to install by hand, that's fine. You may still find it convenient to download the Unified Installer in order to get all the packages together, and you may find it useful to read the UI's install.sh script for ideas on building particular components.

I prefer to use my platform's ports/packages mechanism.

The history of platform packages for Zope and Plone is a troubled one. Platform packages have been of uneven quality and have used installation trees that make it difficult for the community to offer help when problems occur. Also, platform packages have historically been vulnerable to changes in the system Python. Zope/Plone is very picky about the version of Python used to run it, and an update of the system Python when some other item is installed can easily break Zope/Plone. At this point, you may be thinking that this just means that the packages have poorly specified dependencies. The Unified Installer was created because generation after generation of packages did not solve this problem.

Major Unified Installer Options

The Unified Installer for Plone 3 has three major options:

• Install as root or normal user;
• Install as a ZEO Cluster, or a stand-alone Zope;
• Install the full kit, or just a single running instance.

Each of these options are described in a separate section.

Note: Prior versions of the Unified Installer do not have these options

Changes for Plone 3

If you've used the Unified Installer for prior versions of Plone, you'll already know that the options above are new. There are a few additional changes:

• The installation script tries to determine whether or not you need new builds of the libz and libjpeg. If you don't, it won't build them.
• The UI now works more easily with odd-duck platforms like Solaris, where common GNU build tools may be in uncommon locations.
• This version omits some optional products (TextIndexNG#, ReportLab) bundled with prior versions.
• This version includes the new Python easy install kit, though it doesn't use it.

Changes for Plone 3.1

• The Unified Installer now uses buildout to configure Plone instances, which makes it much easier for you to control add-ons and upgrade your Plone installation.
• It's much easier to add additional Zope/Plone instances to an existing install base.
• There are additional options for:
• Controlling the installation target directory;
• Setting a user other than "admin" and/or setting a password of your choice;
• Using an already installed Python 2.4 (possibly the system copy). virtualenv is used to isolate the new installation so that your system Python is not touched.
• If libjpeg or libz installation is required, it's done locally to the new install. Even in a root-mode install, your system libraries are not touched.