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Architecture Decision Record (ADR)

ADR-0043: Architecture levels 1-5 Ultra-light Architecture Decision Record (ADR)

1. Status:

Accepted

2. Context

it/architecture/index.md contained a large Architecture levels 1-5 table directly in the overview page. The table is a concrete architecture decision and reference model, not just introductory index text. Keeping it only in the index page makes the decision harder to reference, review, and evolve in the same way as other accepted architecture rules.

3. Decision

Keep the architecture capability matrix as a dedicated ADR and use the following Architecture levels 1-5 table as the current reference:

Tool Level 1 Level 2
Reserved
Level 3 Level 4
Reserved
Level 5
Standard prog. language set All     All+
Jenkins CI Yes, Single, In-house     Yes, Multi, ?
Docker Registry/Harbor No (?), in CI     Yes
SeleniumHQ cluster (Hub, Nodes) Yes, Single     Yes. Multi
Multi/Single API/ APPs Single     Multi, HA
Multi/Single DBs Single     Multi, HA
Multi/Single Queues (RabbitMQ, Mosquitto) Single     Multi, HA
Multi/Single process engine (Zeebe, Camunda) Single     Multi, HA
Profiles All     All
Poor man’s Wiki (mvn site, .md) Yes     No
Poor man’s Issue Management (Wiki) Yes     No
Poor man’s SonarQube (or similar) - wiki, mvn site Yes     No
Poor man’s Log systems Yes     No
Poor man’s DB (H2/Derby file) Yes     No, Multi, HA
Poor man’s Intra server (Nginx) Yes     No, Multi, HA
Poor man’s CDN (http(s) File server, Nginx) Yes     No, Multi, HA
Poor man’s AI training process loop Yes (existing Jenkins Ci, Zeebe)     No
Poor man’s manual test management (Wiki) Yes     No
K8S ready Yes, K3S     Yes
Service communication over TLS No     Yes
PKI, Key management Minimal, for public web     Yes
Monitoring No (Manual)     Yes
SSH File server Yes, Single, In-house, in CI     Yes
SMTP server per environment Yes     Yes

| IAM (Keycloak) | No | | … | | Yes | | Cloud, Cloud-Hybrid, Private comp. env. | Cloud-Hybrid | | … | | Self made Cloud-Hybrid | | Feature switches level | 2 | | 3 | | 5 | | Multi tenant | Yes | | … | | Yes | | Management tools (Ansible, …) | No | | … | | Yes | | In-house DNS | Yes | | … | | Yes | | In-house DHCP | Yes | | … | | Yes | | In-house LDAP (OpenLDAP) | Yes | | … | | Yes | | In-house SMTP (Sendmail, Postfix, …) | Yes | | … | | … | | Admin tools (b/w simple html, static, SPA, in existing APP) | Yes | | … | | No (Full featured?) | | Monolith (backend reuse, …) | Yes | | … | | No (μS) | | … | … | | … | | … | | … | … | | … | | … | | … | … | | … | | … | | … | … | | … | | … |

4. Rationale (Justification):

Placing the level matrix into its own ADR makes it an explicit architecture baseline instead of a hidden subsection in an overview page. That improves reuse in later ADRs, lets reviews cite one stable decision, and keeps the architecture index shorter and more focused on navigation.

3. Consequences, Impacts & Follow-up Actions

Future updates to architecture maturity levels should modify this ADR instead of reintroducing the table into it/architecture/index.md. The architecture index may link to this ADR, but the normative content for levels 1-5 now lives here.

https://adr.github.io/

Architecture