idk-installer

README

Infrastructure Development Kit Installer

This project is a universal installer for the Infrastructure Development Kit. The installer will run on any system supported by IDK (which is Arch and Ubuntu LTS Linux on ia64 and MacOS for now). It will select, install, and set up newest (or selected) version of IDK with a single command.

The most up-to-date version can always be downloaded from the address https://s3.amazonaws.com/downloads.3ofcoins.net/idk-installer.sh

How do I use it?

Download the script. Run it. IDK should be installed.

To see the archiver's options, run idk-installer.sh --help.

To see the installer's options, run idk-installer.sh -- -help.

How does it work?

The idk-installer.sh script is a compressed Makeself archive. It contains two statically compiled installer binaries, written in Go: one for Linux, and one for Mac OS X (both for 64-bit Intel architecture). When the script runs, the archive unpacks to a temporary directory and a setup shell script is started. This script just looks at current operating system & architecture, and runs appropriate installer binary.

The binary inspects system in more detail, looks for the most recent version (or a version specified on command line) of IDK for the system, downloads the package from S3, installs it, and runs idk setup to configure the system.

Does it have to be so complex?

Possibly not. On the other hand, as of now, this approach seems to provide the best user experience overall:

• There is one installer, user doesn't have to choose between many similar looking Omnibus packages.
• Using a separate installer makes it possible to install and setup IDK in a single pass; adding setup to package's post-install script breaks because chef-solo cookbooks may want to install packages themselves.
• Go binaries provide decent balance between portability (static binaries without external dependencies, so there's one binary per architecture, and only two architectures are supported) and development convenience (writing lowest-common-denominator shell scripts is painful). With Go it is possible to implement some logic in the installer: listing S3 bucket, finding most recent package version, download itself, client system inspection, integrity checks, etc.
• Makeself provides a safe, clean temporary directory to run in - it makes it easy to avoid leaving garbage around.

The downside is that the installer itself is quite big (3MB compressed), and it includes two separate binaries. But remember, we're speaking about installing a 100+MB piece of software that unpacks to 300MB+ directory; I believe that extra convenience and flexibility is worth it. Also, the installer is independent from IDK itself, so it can be cached by IDK and reused for subsequent upgrades. IDK can upgrade the cached installer (which should happen rarely), and the installer can upgrade IDK - no package will need to overwrite itself.