DRAFT: Add docuemnt about Apertis Personalities

Very early stage draft about what Apertis Personalities are about.

Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>

content/concepts/personalities.md

++++
+date = "2021-04-08"
+weight = 100
+
+title = "Apertis Personalities"
+
+outputs = ["html", "pdf-in"]
+
++++
+
+# Overview
+Apertis is an ecosystem of resources that surrounds your product. From a high
+level perspective, we are an aggregator of two software supply chains: the
+Apertis catalog of enterprise-friendly open source software, and the
+proprietary software stack that is specific and private to each product using
+Apertis.
+
+An important part of our day-to-day work is the maintenance of the Apertis
+catalog of open source software. There are three important dimensions: 
+* The Apertis project is active upstream: we consider each upstream project to
+  be our supplier, and our relevance increases with our involvement. We
+contribute upstream to have an open channel to ask for help and to propose
+future directions.
+* The Apertis project is reactive: Because we are part of important upstream
+  communities, and because we understand their code base, we have in-house
+knowledge of how these projects work. Our team can react quickly to any
+disruption, such as a bug, or a security vulnerability.
+* The Apertis project is flexible: Our broad understanding of the open source
+  ecosystem allows us to combine different building blocks to meet the unique
+requirements of any specific product.
+
+Besides the enterprise-friendly catalog of open source software, Apertis is
+also an elaborate set of infrastructure services to support the development and
+testing of the entire software stack of your product. At its lowest level the
+infrastructure is used for the development and testing of Apertis itself, and
+on top of it we encourage you to do the development and testing of the software
+components that are private to your product under the Apertis infrastructure.
+The motivation here is to offer an easy way to follow best practices of
+integration.
+
+As a general principle Apertis is flexible and we allow the developer to choose
+the combination of building blocks that are best suited for each specific
+product. We offer up to package level granularity that allows for precise
+control of which software components will be present in an image. This level of
+customization is important for Apertis, but making all the micro decisions for
+selecting every package is not always desired. Some developers are looking for
+an image to use as a starting point.
+
+At the time of writing this document, we have identified four basic images for
+Apertis: 
+* Fixed function device: represents an appliance or a fixed function setup,
+  meaning that the functionality cannot be extended by installing extra
+software on top of the base system.
+* Industrial IoT device: Similar to the fixed function device as there is
+  little to none user interaction, however these devices are not fixed function
+and are expected to run edge workloads.  These devices are usually intended to
+acquire data from sensors, and then either act on them or relay it to a cloud
+infrastructure. This system can be extended by running containers which are a
+good fit for edge workloads.
+* HMI device: Typically this device will have a modern graphical user interface
+  driven via a touch screen and may include other capabilities such as audio
+input and output. This system can be extended by installing new applications
+using flatpak.
+* SDK: The Apertis software Development Kit is not intended to be the base for
+  a product, but it enables smooth development and comes with all the tooling
+that the developer needs.
+
+This means that there are currently two ways to start creating with Apertis: a
+developer can select the exact set of packages that will compose the image for
+a product, or the developer can use one of the existing images as starting
+point and then adjust the package selection.
+
+These are solid starting points, but even with the scope limited to the
+contents of the image, we already have overlaps of functionality. We expect
+that as the use cases evolve in complexity, contextualizing each use case, and
+each building block becomes a challenge.
+
+We can use Flatpak to illustrate this challenge. Flatpak is a utility for
+software deployment and package management for Linux. It offers a sandbox
+environment in which users can run application software in isolation from the
+rest of the system. When we brought Flatpak into Apertis we had one main use
+case in mind: A device running the HMI image with an appstore. Flatpak is
+suitable for handling the installable applications from a variety of
+perspectives, including security.
+
+However the fact that we brough Flatpak into Apertis does not mean that we will
+force Flatpak on every scenario that includes installable applications. This is
+where the notion of Apertis Personalities becomes relevant. An Apertis
+Personality is the minimal combination of characteristics or qualities that
+form an individual and distinctive Apertis based solution. So for an Apertis
+Personality that uses an appstore for user facing graphical applications,
+Flatpak is a good choice.
+
+Apertis as a project favors flexibility over distinctive choices, and we do so
+by design. While there is a core set of technical and non-technical principles,
+the project offers very broad latitude. In this sense the idea of Apertis
+Personalities allow us to keep the flexibility at a project level while
+offering more value to specific use cases as we allow personalities to
+potentially deviate quite far from one another. 
+
+The scope of an Apertis Personalities goes beyond the content of the image and
+can include: 
+* Cloud services such an appstore or an edge workload orchestrator
+* Software deployment Fleet management
+* Non-functional requirements such as power consumption, and performance
+* Workflows such as development and testing
+* Security features such as trusted boot and TEE
+* ...
+
+Another advantage we expect from Apertis Personalities is to open a new door
+for contributions. Service oriented personalities such as a personality for the
+Bosch IoT suite can be a benefit for Apertis and for the Bosch IoT suite.