Fix HAProxy check for MariaDB

The MariaDB role HAProxy config section exposes MariaDB on the
mariadb_port which may not always be the same as database_port. The
HAProxy role checks that the database_port is free, and not the
mariadb_port. This could mean that the check passes, but the actual
port which HAProxy will attempt to use is taken.

This change configures HAProxy to talk to the MariaDB instances on
the mariadb_port, and maps them to the database_port which is used by
most services as part of the DB connection string.

There is a small risk that it may break someones override config.

Change-Id: I9507ee709cb21eb743112107770ed3170c61ef74

ansible/roles/mariadb/defaults/main.yml

@@ -13,7 +13,8 @@ mariadb_services:
       mariadb:
         enabled: "{{ enable_mariadb|bool and not enable_external_mariadb_load_balancer|bool }}"
         mode: "tcp"
-        port: "{{ mariadb_port }}"
+        port: "{{ database_port }}"
+        listen_port: "{{ mariadb_port }}"
         frontend_tcp_extra:
           - "option clitcpka"
           - "timeout client 3600s"
@@ -25,7 +26,8 @@ mariadb_services:
       mariadb_external_lb:
         enabled: "{{ enable_mariadb|bool and enable_external_mariadb_load_balancer|bool }}"
         mode: "tcp"
-        port: "{{ mariadb_port }}"
+        port: "{{ database_port }}"
+        listen_port: "{{ mariadb_port }}"
         frontend_tcp_extra:
           - "option clitcpka"
           - "timeout client 3600s"

releasenotes/notes/fix-haproxy-database-port-mapping-46bdf2a0ffc253c7.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - MariaDB is now exposed via HAProxy on the ``database_port`` and
+    not the ``mariadb_port``. Out of the box these are both the same,
+    but if you have customised ``mariadb_port`` so that it is different
+    to the ``database_port`` and you have a service talking to it
+    via HAProxy on that port then you should review your configuration.