diff --git a/defaults/main.yml b/defaults/main.yml
index d8dbf01..bf757a2 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -88,6 +88,7 @@ haproxy_service_configs: []
 # haproxy_frontend_raw:
 # - 'http-request use-service prometheus-exporter if { path /metrics }'
 # haproxy_service_enabled: True
+# haproxy_default_backend: other_backend
 
 galera_monitoring_user: monitoring
 haproxy_bind_on_non_local: False
diff --git a/releasenotes/notes/default_backend_override-9840dc75ff9d1a9c.yaml b/releasenotes/notes/default_backend_override-9840dc75ff9d1a9c.yaml
new file mode 100644
index 0000000..e43bf84
--- /dev/null
+++ b/releasenotes/notes/default_backend_override-9840dc75ff9d1a9c.yaml
@@ -0,0 +1,10 @@
+---
+features:
+ - |
+ A new key ``haproxy_default_backend`` can be defined for each service
+ configured in the haproxy loadbalancer. Configuring this variable writes
+ a value for the ``default_backend`` directive into the config for the
+ service frontend. It can be useful to provide a specific default backend
+ as a fall-through option when other backends are selected using ACLs,
+ and to also allow the name of the default backend to be different from
+ ``haproxy_service_name``.
diff --git a/templates/service.j2 b/templates/service.j2
index 371e2b8..3d7c7fb 100644
--- a/templates/service.j2
+++ b/templates/service.j2
@@ -83,8 +83,8 @@ frontend {{ item.service.haproxy_service_name }}-front-{{ loop.index }}
 http-request add-header X-Forwarded-Proto https
 {% endif %}
 mode {{ item.service.haproxy_balance_type }}
-{% if not item.service.haproxy_frontend_only | default(false) %}
- default_backend {{ item.service.haproxy_service_name }}-back
+{% if (not item.service.haproxy_frontend_only | default(false)) or ((item.service.haproxy_default_backend is defined) and (item.service.haproxy_default_backend | length> 0)) %}
+ default_backend {{ item.service.haproxy_default_backend | default(item.service.haproxy_service_name) }}-back
 {% endif %}
 {% for entry in (item.service.haproxy_frontend_raw|default([])) + haproxy_frontend_extra_raw %}
 {{ entry }}
</div><div class="naked_ctrl">
<form action="/index.cgi/contrast" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://opendev.org/openstack/openstack-ansible-haproxy_server/commit/42d80464af27b60c8fa57a20be782040a3d6924b.diff">(-&gt;オリジナル)</a>
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<option value="default">デフォルト</option>
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<input type="submit" value="表示" />
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