service: Make supporting containers accessible using simple hostnames

roles/service/meta/argument_specs.yaml

@@ -244,9 +244,9 @@ argument_specs:
           - Database type to set up.
           - >
             It will be run in a container accessible to the service at
-            host {{ service_name }}-{{ service_database_type }} on the default port.
+            host <service database type> on the default port.
-          - The database user will be {{ service_name }}
+          - The database user will be <service name>
-          - The password will be accessible as secret at /run/secrets/{{ service_database_type }}
+          - The password will be accessible as secret at /run/secrets/<service database type>
           - >
             The password will also be available as the
             service_podman_secrets['{{ service_name }}-{{ service_database_type }}'] variable.
@@ -293,8 +293,7 @@ argument_specs:
         required: false
       service_redis:
         description: >-
-          Whether to install redis in a container accessible to the service at host
+          Whether to install redis in a container accessible to the service at host redis.
-          {{ service_name }}-redis.
         type: bool
         required: false
         default: false

roles/service/tasks/additional.yaml

@@ -13,6 +13,7 @@
     container_networks: "{{ _service_container_networks }}"
     container_ip: "{{ _service_additional_container_ip }}"
     container_secrets: "{{ _service_additional_container.secrets | default(_service_container_secrets) }}"
+    container_hostname: "{{ _service_additional_container.name | regex_replace('^' ~ service_name ~ '-', '') }}"
     container_env: "{{ _service_additional_container.env | default(service_container_env) }}"
     container_requires: "{{ _service_container_requires }}"
     container_wants: "{{ service_wants }}"

roles/service/tasks/database.yaml

@@ -14,6 +14,7 @@
         source: "{{ _service_database_name }}"
         destination: "{{ _service_database_mount_destination }}"
     container_networks: "{{ _service_database_networks }}"
+    container_hostname: "{{ service_database_type }}"
     container_ip: >-
       {{ service_container_ip | ansible.utils.ipmath(1) if _service_static_ip else '' }}
     container_secrets:

roles/service/tasks/redis.yaml

@@ -7,6 +7,7 @@
     container_image: docker.io/valkey/valkey:alpine
     container_networks:
       - "{{ service_name }}"
+    container_hostname: redis
     container_ip: >-
       {{ service_container_ip | ansible.utils.ipmath(2) if _service_static_ip else '' }}
     container_auto_update: "{{ service_auto_update }}"