Applications Development & Deployment

Deployment activities

Release. The release activity follows from the completed development process, and is sometimes classified as part of the development process rather than deployment process. It includes all the operations to prepare a system for assembly and transfer to the computer system(s) on which it will be run in production. Therefore, it sometimes involves determining the resources required for the system to operate with tolerable performance and planning and/or documenting subsequent activities of the deployment process.

Installation and activation. For simple systems, installation involves establishing some form of command, shortcut, script or service for executing the software (manually or automatically). For complex systems it may involve configuration of the system – possibly by asking the end-user questions about its intended use, or directly asking them how they would like it to be configured – and/or making all the required subsystems ready to use. Activation is the activity of starting up the executable component of software for the first time (not to be confused with the common use of the term activation concerning a software license, which is a function of Digital Rights Management systems.)

In larger software deployments on servers, the main copy of the software to be used by users - "production" - might be installed on a production server in a production environment. Other versions of the deployed software may be installed in a test environment, development environment and disaster recovery environment.

In complex continuous delivery environments and/or software as a service systems, differently-configured versions of the system might even exist simultaneously in the production environment for different internal or external customers (this is known as a multi-tenant architecture), or even be gradually rolled out in parallel to different groups of customers, with the possibility of cancelling one or more of the parallel deployments. For example, Twitter is known to use the latter approach for A/B testing of new features and user interface changes. A "hidden live" group can also be created within a production environment, consisting of servers that are not yet connected to the production load balancer, for the purposes of blue-green deployment.

Deactivation. Deactivation is the inverse of activation, and refers to shutting down any already-executing components of a system. Deactivation is often required to perform other deployment activities, e.g., a software system may need to be deactivated before an update can be performed. The practice of removing infrequently used or obsolete systems from service is often referred to as application retirement or application decommissioning.

Uninstallation. Uninstallation is the inverse of installation. It is the removal of a system that is no longer required. It may also involve some reconfiguration of other software systems in order to remove the uninstalled system’s dependencies.

Update. The update process replaces an earlier version of all or part of a software system with a newer release. It commonly consists of deactivation followed by installation. On some systems, such as on Linux when using the system's package manager, the old version of a software application is typically also uninstalled as an automatic part of the process. (This is because Linux package managers do not typically support installing multiple versions of a software application at the same time, unless the software package has been specifically designed to work around this limitation.)

Built-in update. Mechanisms for installing updates are built into some software systems (or, in the case of some operating systems such as Linux, Android and iOS, into the operating system itself). Automation of these update processes ranges from fully automatic to user initiated and controlled. Norton Internet Security is an example of a system with a semi-automatic method for retrieving and installing updates to both the antivirus definitions and other components of the system. Other software products provide query mechanisms for determining when updates are available.

Version tracking. Version tracking systems help the user find and install updates to software systems. For example: Software Catalog stores version and other information for each software package installed on a local system. One click of a button launches a browser window to the upgrade web page for the application, including auto-filling of the user name and password for sites that require a login. On Linux, Android and iOS this process is even easier because a standardised process for version tracking (for software packages installed in the officially supported way) is built into the operating system, so no separate login, download and execute steps are required – so the process can be configured to be fully automated. Some third-party software also supports automated version tracking and upgrading for certain Windows software packages.

Adaptation. The adaptation activity is also a process to modify a software system that has been previously installed. It differs from updating in that adaptations are initiated by local events such as changing the environment of customer site, while updating is a consequence of a new release being made available. Adaptation may require specialist technical skills such as computer programming, in certain complex cases.