docs: cite db creation syntax and fix service name

Document how to properly create target database as required by currently
documented dump strategy. Also fix the service name we restore against
to be the primary host as `mariadb-cluster` may resolve to a secondary
node resulting in unexpected restore issues.

docs/infrastructure-mariadb-ops.md

@@ -20,6 +20,8 @@ mysql -h $(kubectl -n openstack get service mariadb-cluster-primary -o jsonpath=
 
 When running `mysqldump` or `mariadbdump` the following commands can be useful for generating a quick backup.
 
+### Individual Database Backups
+
 ``` shell
 mysqldump --host=$(kubectl -n openstack get service mariadb-cluster -o jsonpath='{.spec.clusterIP}')\
           --user=root \
@@ -53,10 +55,24 @@ mysqldump --host=$(kubectl -n openstack get service mariadb-cluster -o jsonpath=
                   --result-file=/tmp/{}-$(date +%s).sql
     ```
 
+### Individual Database Restores
+
+!!! tip "Ensure the destination database exists"
+
+    The destination database must exist prior to restoring individual SQL
+    backups. If it does not already exist, it's important to create the
+    database with the correct charset and collate values. Failing to do so can
+    result in errors such as `Foreign Key Constraint is Incorrectly Formed`
+    during DB upgrades.
+
+    ```
+    CREATE DATABASE ${DATABASE_NAME} DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_general_ci;
+    ```
+
 !!! example "Restoring a database"
 
     ``` shell
-    mysql -h $(kubectl -n openstack get service mariadb-cluster -o jsonpath='{.spec.clusterIP}') \
+    mysql -h $(kubectl -n openstack get service mariadb-cluster-primary -o jsonpath='{.spec.clusterIP}') \
         -u root \
         -p$(kubectl --namespace openstack get secret mariadb -o jsonpath='{.data.root-password}' | base64 -d) \
         ${DATABASE_NAME} < /tmp/${DATABASE_FILE}