Openshift with its Kubernetes, Docker and Addons builds the heart of AppAgile. But AppAgile is more than just Openshift. AppAgile is a complete PaaS. To achieve this, AppAgile adds some layers around Openshift. The layer Central Components adds infrastructural components for operational purposes like Monitoring, Logging and Backup. Furthermore it adds User and Identity Management and a central Docker Repository. Within this repository, AppAgile provides images to the platform. The Storage layer adds persistent storage to the platform that can be used by user applications.
The Openshift Architecture will not be part of this guide as it can be found in the openshift documentation. This guide will focus on the benefits of AppAgile.
To gain an impression of the responsibilty and purpose of the components each of them will be described briefly in the following.
The layer Central Components adds components for operational and infrastructural purposes.
This component’s responsibility is to ensure that infrastructure is up and running properly on an operational level. Furthermore it monitors events on the application level since the platform is been operated as a managed platform.
The central logging component collects system logging files of each infrastructure component of the platform on an operational level. Furthermore it collects logging data on the application level since the platform is been operated as a managed platform.
This component acts as a central backup system for all platform components on the platform infrastructure level by default in order to recover the platform in case of a platform crash. If running on a managed platform, data on the application level will also be backed up.
Docker images provided by T-Systems are lcoated in a docker registry within the central layer inside the data centre of T-Systems. This registry consists of images that are approved by T-Systems.
User & Identity Management
Users who have access to the platform will be managed within this component.
At the heart of AppAgiles PaaS is Openshift. Openshift provides a Platform as a Service, where developers and teams can build, test, run and manage their applications. A detailed documentation can be found at Red Hats Openshift documentation. Please refer to the appendix to find the proper reference.
By default, applications running on a cloud platform are using ephemeral storage. So let’s say applications provide their own storage at startup and release it when the application terminates, i.e. application data will get lost. That is a quite common cloud pattern. But sometimes it is required that application data will not get lost when applications are terminated, for example a database. Data should reside on a persistent storage. More information on storage, see Persistent Storage.
AppAgile is independent from the infrastructure. It can be run on serveral infrastructures, like vCloud, Open Telekom Cloud, Azure and even on Bare-metal.