MariaDB Architecture

Compose 🐳

flowchart LR
    subgraph role [svc-db-mariadb]
        svc_mariadb["mariadb<br>mariadb:13.0<br>mariadb 3306"]
    end

Swarm 🐝

flowchart LR
    svc_mariadb["mariadb"]
    svc_mariadb --> rep_mariadb["replicas: from the host group"]
    svc_mariadb --> plc_mariadb["node.role == manager"]:::pinned
    classDef pinned fill:#fef7e0,stroke:#b06000,color:#3d2600;

Volumes

flowchart LR
    vol_data["mariadb_data"]
    vol_data -->|"role is manager-pinned"| local_data["node-local on the manager"]:::local
    classDef shared fill:#e6f4ea,stroke:#137333,color:#0b2e13;
    classDef local fill:#fef7e0,stroke:#b06000,color:#3d2600;

Condition	Effect
swarm, storage.backend: nfs, no nfs: false, role not pinned	shared over NFS
any one of those missing	node-local

All four conditions must hold, so pinning a role takes every one of its volumes node-local. Only the role’s primary entry counts as pinned here: a placement on any other service pins that service alone and leaves the backing of every volume unchanged. The chain is drawn rather than its result, because that coupling is what makes a placement change move data without saying so.

Dependencies

flowchart LR
    subgraph deps [Dependencies]
        dep_svc_bkp_volume_2_local["svc-bkp-volume-2-local 💻"]
        dep_svc_net_tor["svc-net-tor 🐳🐝"]
        dep_web_app_docs["web-app-docs 🐳🐝"]
    end
    subgraph role [svc-db-mariadb 🐳🐝]
        svc_mariadb["mariadb"]
        svc_tor["tor"]
        svc_container_backup["container_backup"]
        svc_docs["docs"]
    end
    subgraph dependents [Dependents]
        dpt_web_app_akaunting["web-app-akaunting 🐳🐝"]
        dpt_web_app_erpnext["web-app-erpnext 🐳🐝"]
        dpt_web_app_espocrm["web-app-espocrm 🐳🐝"]
        dpt_web_app_friendica["web-app-friendica 🐳🐝"]
        dpt_web_app_gitea["web-app-gitea 🐳🐝"]
        dpt_web_app_joomla["web-app-joomla 🐳🐝"]
        dpt_web_app_mailu["web-app-mailu 🐳🐝"]
        dpt_web_app_matomo["web-app-matomo 🐳🐝"]
        dpt_web_app_mediawiki["web-app-mediawiki 🐳🐝"]
        dpt_web_app_moodle["web-app-moodle 🐳🐝"]
        dpt_web_app_nextcloud["web-app-nextcloud 🐳🐝"]
        dpt_web_app_phpmyadmin["web-app-phpmyadmin 🐳🐝"]
        dpt_web_app_pixelfed["web-app-pixelfed 🐳🐝"]
        dpt_web_app_shopware["web-app-shopware 🐳🐝"]
        dpt_web_app_snipe_it["web-app-snipe-it 🐳🐝"]
        dpt_web_app_suitecrm["web-app-suitecrm 🐳🐝"]
        dpt_web_app_wordpress["web-app-wordpress 🐳🐝"]
        dpt_web_app_yourls["web-app-yourls 🐳🐝"]
    end
    dep_svc_bkp_volume_2_local -. "0..1" .-> svc_container_backup
    dep_svc_net_tor -. "0..1" .-> svc_tor
    dep_web_app_docs -. "0..1" .-> svc_docs
    svc_mariadb -. "0..1" .-> dpt_web_app_akaunting
    svc_mariadb -. "0..1" .-> dpt_web_app_erpnext
    svc_mariadb -. "0..1" .-> dpt_web_app_espocrm
    svc_mariadb -. "0..1" .-> dpt_web_app_friendica
    svc_mariadb -. "0..1" .-> dpt_web_app_gitea
    svc_mariadb -. "0..1" .-> dpt_web_app_joomla
    svc_mariadb -. "0..1" .-> dpt_web_app_mailu
    svc_mariadb -. "0..1" .-> dpt_web_app_matomo
    svc_mariadb -. "0..1" .-> dpt_web_app_mediawiki
    svc_mariadb -. "0..1" .-> dpt_web_app_moodle
    svc_mariadb -. "0..1" .-> dpt_web_app_nextcloud
    svc_mariadb -. "0..1" .-> dpt_web_app_phpmyadmin
    svc_mariadb -. "0..1" .-> dpt_web_app_pixelfed
    svc_mariadb -. "0..1" .-> dpt_web_app_shopware
    svc_mariadb -. "0..1" .-> dpt_web_app_snipe_it
    svc_mariadb -. "0..1" .-> dpt_web_app_suitecrm
    svc_mariadb -. "0..1" .-> dpt_web_app_wordpress
    svc_mariadb -. "0..1" .-> dpt_web_app_yourls

Symbol	Meaning
1:1 solid	fixed relationship
0..1 dashed	conditional, enabled only in matching deployments
0..0 red	declared but turned off in this role
💻	deploys to the host
🐳	deploys under compose
🐝	deploys under swarm
❌	service explicitly turned off
⚙️	Ansible role dependency from meta/main.yml

Every dependency and dependent is listed; the graph is not truncated.