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Introduction

What is EasyBuild?

EasyBuild is a software build and installation framework that manages (scientific) software in an efficient way, without compromises on performance. Easybuild is especially tailored towards High Performance Computing (HPC) environments.

Elevator pitch

EasyBuild intends to relieve HPC support teams from manually managing software installations while at the same time providing a consistent and well performing scientific software stack to end users of HPC systems.

It serves as a uniform interface for installing scientific software and saves valuable time (and frustration) by the automation of tedious, boring and repetitive tasks.

In addition, EasyBuild can empower scientific researchers to self-manage their software stack, and it can serve as a tool that can be leveraged for building optimized container images.

The project has grown to become a platform for collaboration among worldwide HPC sites.

Key features

EasyBuild is capable of fully autonomously installing (scientific) software, including making sure that all necessary dependencies are installed, and automatically generating environment module files.

No admin privileges are required: it is sufficient to have write permissions to the preferred software installation prefix.

It is highly configurable via configuration files, environment variables, and command line options. The functionality can be dynamically extended via plugins, and hooks are available for further site-specific customizations if required.

The installation procedure executed by EasyBuild is thoroughly logged and fully transparent via dry runs and tracing.

EasyBuild supports using a custom module naming scheme, allows for hierarchical module naming schemes, and integrates with various other tools ranging from resource managers (Slurm and GC3Pie), container tools (Singularity and Docker), packaging tools (FPM), and so on.

The project is actively developed by a worldwide community, with stable versions being released every 6-8 weeks since 2012. Comprehensive testing practices are applied throughout the development cycle, with extensive suites of unit and integration tests being run in a CI environment, consistent testing of incoming contributions, and thorough regression testing before every release.

What EasyBuild is not

EasyBuild is not YABT (Yet Another Build Tool): it does not replace established build tools like CMake or make, it wraps around them. If the installation procedure of a software package involves running some unholy trinity of tools while whispering the correct magic incantations, EasyBuild automates this process for you.

It is not a replacement for traditional Linux package managers like yum, dnf or apt. EasyBuild relies on certain tools and libraries provided by the operating system. This includes glibc, OpenSSL, Infiniband, GPU drivers, and so on. It is required that these tools are installed and managed by other means. This is typically done via the package management tool that comes with your Linux distribution.

Finally, EasyBuild is not a magic solution to all your (software installation) problems. You may, and probably will still occasionally, run into compiler errors unless somebody has already taken care of the problem for you.

Implementation

EasyBuild is implemented in Python, and fully supports both Python 2.7 and 3.5+.

Releases are published via PyPI, under the GPLv2 open source license.

Development is done through the easybuilders organisation on GitHub, where each of the EasyBuild components is hosted in a separate repository.


Terminology

Over the years, we have come up with some terminology specific to EasyBuild to refer to particular components, which we use alongside established terminology relevant to the context of building and installing software.

It is important to be familiar with these terms.

Framework

The EasyBuild framework consists of a set of Python modules organised in packages (easybuild.framework, easybuild.tools, etc.) that collectively form the heart of EasyBuild.

It implements the common functionality that you need when building software from source, providing functions for unpacking source files, applying patch files, collecting the output produced by shell commands that are being run and checking their exit code, generating environment module files, etc.

The EasyBuild framework does not implement any specific installation procedure, it only provides the necessary functionality to facilitate this (see easyblocks).

Easyblocks

An easyblock is a Python module that implements a specific software installation procedure. It can be viewed as a plugin to the EasyBuild framework.

Easyblocks can be either generic or software-specific.

A generic easyblock implements an installation procedure that can be used for multiple different software packages. Commonly used examples include the ConfigureMake easyblock which implements the ubiquitous configure-make-make install procedure, and the PythonPackage easyblock that can be used to install a Python package.

A software-specific easyblock implements an installation procedure that is specific to a particular software packages. Infamous examples include the easyblocks we have for GCC, OpenFOAM, TensorFlow, ...

The installation procedure performed by an easyblock can be controlled by defining easyconfig parameters (see easyconfig files).

Easyconfig files

Easyconfig files (or easyconfigs for short), are simple text files written in Python syntax that specify what EasyBuild should install. They define the different easyconfig parameters that collectively form a complete specification for a particular software installation.

Some easyconfig parameters are mandatory. The following parameters must be defined in each easyconfig file:

  • name and version, which specify the name and version of the software to install (surprise!);
  • homepage and description, which provide key metadata for the software;
  • toolchain, which specifies the compiler toolchain to use to install the software (see toolchains tab);

Other easyconfig parameters are optional: they can be used to provide required information, or to control specific aspects of the installation procedure performed by the easyblock.

Some commonly used optional easyconfig parameters include:

  • easyblock, which specifies which (generic) easyblock should be used;
  • sources and source_urls, which specify the list of source files and where to download them;
  • dependencies and builddependencies, which specify (drum roll...) the list of (build) dependencies;
  • configopts, buildopts, and installopts, which specify options for the configuration/build/install commands, respectively;

If these parameters are not provided, the corresponding default value will be used.

Extensions

Extensions is the collective term we use for additional software packages that can be installed on top of another software package. Examples are Python packages, R libraries and Perl modules.

As you can tell the common terminology here is a mess, so we came up with a unifying term...

Extensions can be installed in different ways:

  • stand-alone, as a separate installation on top of one or more other installations;
  • as a part of a bundle of extensions that collectively form a separate installation;
  • or as an actual extension to a specific installation to yield a "batteries included" type of installation (for examples by adding a bunch of Python packages from PyPI into a Python installation);

Dependencies

A dependency is a common term in the context of software. It refers to a software package that is either strictly required by other software, or that can be leveraged to enhance other software (for example to support specific features).

There are three main types of dependencies for computer software:

  • a build dependency is only required when building/installing a software package; once the software package is installed, it is no longer needed to use that software;
  • a runtime dependency (often referred to simply as dependency) is a software package that is required to use (or run) another software package;
  • a link-time dependency is somewhere in between a build and runtime dependency: it is only needed when linking a software package; it can become either a build or runtime dependency, depending on exactly how the software is installed;

The distinction between link-time and build/runtime dependencies is irrelevant for this tutorial.

Toolchains

A compiler toolchain (or just toolchain for short) is a set of compilers, which are used to build software from source, together with a set of additional libraries that provide further core functionality.

We refer to the different parts of a toolchain as toolchain components.

The compiler component typically consists of C, C++, and Fortran compilers in the context of HPC, but additional compilers (for example, a CUDA compiler for GPGPU software) can also be included.

Additional toolchain components are usually special-purpose libraries:

  • an MPI library to support distributed computations (for example, Open MPI);
  • libraries providing efficient linear algebra routines (BLAS, LAPACK);
  • a library supporting computing Fast Fourier Transformations (for example, FFTW);

A toolchain that includes all of these libraries is referred to as a full toolchain, while a subtoolchain is a toolchain that is missing one or more of these libraries. A compiler-only toolchain only consists of compilers (no additional libraries).

System toolchain

The system toolchain is a special case which corresponds to using the system-provided compilers and libraries, rather than using toolchain components that were installed using EasyBuild.

It used sparingly, mostly to install software where no actual compilation is done or to build a set of toolchain compilers and its dependencies, since the versions of the system tools and libraries are beyond the control of EasyBuild, which could affect the reproducibility of the installation.

Common toolchains

The foss and intel toolchains are also known as the common toolchains, because they are widely adopted by the EasyBuild community.

The foss toolchain consists of all open source components (hence the name: "FOSS" stands for Free & Open Source Software): GCC, Open MPI, OpenBLAS, ScaLAPACK and FFTW.

The intel toolchain consists of the Intel C, C++ and Fortran compilers (on top of a GCC version controlled through EasyBuild) alongside the Intel MPI and Intel MKL libraries.

Roughly every 6 months, a new version of these common toolchains is agreed upon in the EasyBuild community, after extensive testing.

More information on these toolchains is available in the EasyBuild documentation.

Modules

Module is a massively overloaded term in (scientific) software and IT in general (kernel modules, Python modules, and so on). In the context of EasyBuild, the term 'module' usually refers to an environment module (file).

Environment modules is a well established concept on HPC systems: it is a way to specify changes that should be made to one or more environment variables in a shell-agnostic way. A module file is usually written in either Tcl or Lua syntax, and specifies which environment variables should be updated, and how (append, prepend, (re)define, undefine, etc.) upon loading the environment module. Unloading the environment module will restore the shell environment to its previous state.

Environment module files are processed via a modules tool, of which there are several conceptually similar yet slightly different implementations. The Tcl-based Environment Modules implementation, and Lmod, a more recent Lua-based implementation (which also supports module files written in Tcl syntax), are the most commonly used ones.

EasyBuild heavily relies on environment modules, and hence having a modules tool installed is a strict requirement in order to use EasyBuild. Both Lmod and the Tcl-based Environment Modules tools are supported by EasyBuild, as well as module files in both Tcl and Lua syntax.

Module files are automatically generated for each software installation by EasyBuild, and loading a module results in changes being made to the environment of the current shell session such that the corresponding software installation can be used.

Bringing it all together

The EasyBuild framework leverages easyblocks to automatically build and install (scientific) software, potentially including additional extensions, using a particular compiler toolchain, as specified in easyconfig files.

EasyBuild ensures that the specified dependencies are in place, and automatically generates a set of (environment) modules that facilitate access to the installed software.


Focus points

EasyBuild was created specifically for installing scientific software on HPC systems, which is reflected in some of the design choices that were made.

Performance

EasyBuild strongly prefers to build software from source code, whenever possible.

This is important to ensure that the binaries that are installed can maximally exploit the capabilities of the system architecture on which the software will be run.

For that same reason, EasyBuild optimizes software for the processor architecture of the build host by default, via compiler options like -march=native (GCC), -xHost (Intel compilers), etc. This behaviour may be changed via the --optarch configuration setting.

Reproducibility

In addition to performance, reproducibility of installations is a core aspect of EasyBuild.

Most software installations performed with EasyBuild use a particular toolchain, with which we aim to take control over the build environment and avoid relying on tools and libraries provided by the operating system. For similar reasons, we try to provide all required dependencies through EasyBuild as well, with a few notable exceptions, like OpenSSL for security reasons, and Infiniband and GPU drivers which are too closely intertwined with the operating system.

For both toolchains and dependencies, fixed software versions are specified in the easyconfig files. That way, easyconfig files can easily be shared with others: if they worked for you it is very likely that they will work for others too, because the vast majority of the software stack is controlled by EasyBuild.

Community effort

In a number of different ways, we try to encourage EasyBuild users to collaborate and help each other out.

We actively recommend people to report problems and bugs, to submit ideas for additional features and improvements, and to contribute back when possible, be it by opening pull requests to the EasyBuild framework, easyblocks, easyconfigs repositories, or to the EasyBuild documentation.

Through the foss and intel common toolchains, we try to focus the efforts of the EasyBuild community a bit to specific toolchains, which increases the usefulness of the easyconfig files we collect in the central repository.

Last but not least, EasyBuild provides various GitHub integration features that greatly facilitate the contribution process: opening, updating, and testing pull requests, reviewing incoming contributions, and much more can all be done directly from the EasyBuild command line. This not only saves time, effort, brain cycles, and mouse clicks for contributors, but it also makes the review process for maintainers significantly easier. All together this leads to improved stability and consistency.


Last update: March 6, 2021