container: Support setting container hostname

roles/container/defaults/main.yaml

@@ -6,6 +6,7 @@ container_mounts: []
 container_devices: []
 container_publish_ports: []
 container_networks: []
+container_hostname: ""
 container_ip: ""
 container_secrets: []
 container_env: {}

roles/container/meta/argument_specs.yaml

@@ -119,11 +119,17 @@ argument_specs:
         required: false
         default: []
         elements: str
+      container_hostname:
+        description: Hostname to set inside the container. Available to other containers on the same network.
+        type: str
+        required: false
+        default: ""
       container_ip:
         description: IPv4 address for the container in the first network defined in container_networks
         type: str
         required: false
         default: ""
+
       container_secrets:
         description: A list of secrets available to the container as file or environment variable
         type: list

roles/container/tasks/main.yaml

@@ -50,6 +50,7 @@
     mount: "{{ _container_mounts | map('items') | map('map', 'join', '=') | map('join', ',') }}"
     device: "{{ _container_devices }}"
     network: "{{ _container_networks_with_ip }}"
+    hostname: "{{ container_hostname or omit }}"
     publish: "{{ container_publish_ports }}"
     secrets: "{{ _container_secrets }}"
     env: "{{ container_env }}"