DNS naming scheme

The DNS naming scheme fulfills the usability requirements documented in DNS Naming scheme.

Base domain

The base domain is appuio.cloud.

Common services that are zone independent are served on the third level. Services bound to a specific APPUiO Zone, will be served through the fourth level where the third level is the zone’s identifier. Apps served through am APPUiO Zone’s default domain use the subdomain apps of a zone’s base domain.

Table 1. Known hosts and schemes of 'appuio.cloud'
Hostname	Description
`appuio.cloud`, `www.appuio.cloud`	Hosting the marketing homepage for APPUiO Cloud
`id.appuio.cloud`	Identity provider for APPUiO Cloud
`portal.appuio.cloud`	Frontend to manage cross zone concerns
`console.<zone>.appuio.cloud`	OpenShift console frontend of an APPUiO Zone
`api.<zone>.appuio.cloud`	Kubernetes API endpoint (for example for KubeConfig)
`logging.<zone>.appuio.cloud`	Frontend for the OpenShift logging service (Kibana)
`registry.<zone>.appuio.cloud`	Container registry
`cname.<zone>.appuio.cloud`	The DNS entry where users can point CNAME entries to
`<app>.apps.<zone>.appuio.cloud`	A hostname hosted on an APPUiO Zone relying on the zone’s default app domain.

The content of the <app> placeholder is provided by an OpenShift Route object that defaults to the name of the Route object and the namespace it is located in. Users are always free to use hostnames under their control (for example CNAME entries) to expose their applications running on the platform.

What goes into <zone> placeholder is covered by the next section.

Using a single domain conveys that this all belongs together. The domains are as short as possible and therefore are memorable. They can also be typed manually without being a big hurdle. As they are following a simple pattern, a versed person should be able to guess them.

Technical sidenote: By current standards, reading cookies are limited by the "same origin" policy. For this, there is no need to use separate domains.

Zone

The APPUiO Zone identifier follows the pattern:

<provider>: Name of the cloud provider the cluster is hosted on (see below).
<region>: Region name, taken verbatim (lowercase) from the cloud provider’s own naming scheme (rma, ch-dk-2, eu-central-1, switzerlandnorth, europe-west6).
<index>: Zero indexed numerical identifier.

Example 1. Examples of APPUiO Zone domains

cloudscale-rma-0.appuio.cloud first cluster hosted on Cloudscale and placed in the region located in Rümlang.
exoscale-ch-dk-2-2.appuio.cloud third cluster hosted on Exoscale and placed in the region located in Zürich.
aws-eu-central-1-1.appuio.cloud second cluster hosted on AWS and placed in the region located in Frankfurt.

Table 2. Known cloud providers
Provider	Full name
`cloudscale`	cloudscale.ch
`exoscale`	Exoscale
`aws`	Amazon Web Services
`gcp`	Google Cloud Platform
`azure`	Microsoft Azure

On Cloudscale, you will most likely only see rma1 and lpg1. One is inclined to assume those are the regions, but actually, those are the zones. As Cloudscale only has one zone per region, it is easy to confuse one for the other.