The European Environment for Scientific Software Installations (EESSI, pronounced as “easy”) is a collaboration between different HPC sites and industry partners, with the common goal to set up a shared repository of scientific software installations that can be used on a variety of systems, regardless of which flavor/version of Linux distribution or processor architecture is used, or whether it is a full-size HPC cluster, a cloud environment or a personal workstation. The concept of the EESSI project was inspired by the Compute Canada software stack, and consists of three main layers: - a filesystem layer leveraging the established CernVM-FS technology, to globally distribute the EESSI software stack; - a compatibility layer using Gentoo Prefix, to ensure compatibility with different client operating systems (different Linux distributions, macOS, Windows Subsystem for Linux); - a software layer, hosting optimized installations of scientific software along with required dependencies, which were built for different processor architectures, and where archspec, EasyBuild and Lmod are leveraged. We use Ansible for automating the deployment of the EESSI software stack. Terraform is used for creating cloud instances which are used for development, building software, and testing. We also employ ReFrame for testing the different layers of the EESSI project, and the provided installations of scientific software applications. Finally, we use Singularity containers for having clean software build environments and for providing easy access to our software stack, for instance on machines without a native CernVM-FS client. In this talk, we will present how the EESSI project grew out of a need for more collaboration to tackle the challenges in the changing landscape of scientific software and HPC system architectures. The project structure will be explained in more detail, covering the motivation for the layered approach and the choice of tools, as well as the lessons learned from the work done by Compute Canada. The goals we have in mind and how we plan to achieve them going forward will be outlined. Finally, we will demonstrate the current pilot version of the project, and give you a feeling of the potential impact.