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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