Instanz
What is an instance in IT?
In IT, there are two different meanings for the term instance:
- In terms of infrastructure, an instance is a functional unit of an IT component that is associated with a set of users.
- In object-oriented programming (OOP), an instance, or instantiation, is the creation of an object from a class.
Here we are only concerned with the first.
Virtualization
Originally, an instance in IT was a fully functional part of the operating system of a mainframe computer in a data center. Thanks to modern server virtualization, logic and physical resources can now be separated from each other, so that a large number of different instances can be operated in parallel on one host.
Each instance can have individually allocated processors, its own disk space and RAM (main memory). Their provisioning, management and scaling is therefore very flexible.
Instances can be created from anything that is concrete and self-contained. This can range from a complete server, to applications, to individual files.
Tenants
Since virtualization makes it easy to create a large number of instances of the same software application, these can be made available to different groups of users, also known as clients.
The principle of the instance explained using the example of the Cloudogu EcoSystem
The Cloudogu EcoSystem is a virtual machine in which applications are operated in containers, so-called Dogus. It is a concrete and self-contained software of which any number of instances can be created.
Each instance of the Cloudogu EcoSystem is thus its own platform that can include an individual set of applications. The available tools include applications from all areas of the Software Development Lifecycle and are interconnected. They thus map the typical process of software development with corresponding tools.
It is possible that individual instances can provide different sets of tools according to the individual needs of a client.
Since each instance of the Cloudogu EcoSystem is a virtual machine, it is very easy to copy, migrate, backup, duplicate or scale. Depending on your own requirements, it may make sense to run all projects in one Cloudogu EcoSystem instance or to run multiple instances in parallel. We have given suggestions on how to operate multiple instances in this blog post.