Proxmox is an open source server virtualisation environment, with no limits on its use. Its Debian-based kernel allows the deployment and management of virtual machines and containers without operating system incompatibility. It can be installed on any number of "physical servers". One of the most relevant features in the latest versions of Proxmox is the creation of clusters when there are at least 2 physical servers with this environment installed. The high availability is an advantage for system or network administrators, as it allows Proxmox to be programmed to respond to any failure and not affect the network services offered in the company. How to install Proxmox in its version 5.1, the creation of the cluster with 3 physical servers, the installation of external storage (NFS), creating the high availability (HA) and the programming of the same will be addressed in this work.