Software downtime refers to the time when software is unavailable or its operation is prevented for some reason. New software installations, migrations and upgrades cause downtime in the system which leads to loss in revenue and reduced general level of service for the company. Difficult part is finding the right set of tools and practices that minimize this downtime at different stages of software’s deployment. Choosing the right tools that are compatible with company’s infrastructure is also challenging and typically happens through trial and error. The focus of this thesis is to study different means to reduce downtime during software deployment. Study focuses on reviewing tools and practices that can be used to deliver and deploy software to a production environment without service interruption. The research was carried out as literature review by examining the documents and materials from different sources.