Enable HAProxy backend checks for Ceph RGW

Add the `check` option to server definitions to enable basic HAProxy health
checks for Ceph RADOS gateway backends.

Currently traffic will be forwarded to unhealthly `radosgw.service` servers.
These changes resolve the issue.

Signed-off-by: Niko Smeds nikosmeds@gmail.com
(cherry picked from commit a951c1a)

roles/ceph-rgw-loadbalancer/templates/haproxy.cfg.j2

@@ -43,9 +43,9 @@ frontend rgw-frontend
 backend rgw-backend
     option forwardfor
     balance static-rr
-    option httpchk Get /
+    option httpchk HEAD /
 {% for host in groups[rgw_group_name] %}
 {% for instance in hostvars[host]['rgw_instances'] %}
-	server {{ 'server-' + hostvars[host]['ansible_hostname'] + '-' + instance['instance_name'] }} {{ instance['radosgw_address'] }}:{{ instance['radosgw_frontend_port'] }} weight 100
+	server {{ 'server-' + hostvars[host]['ansible_hostname'] + '-' + instance['instance_name'] }} {{ instance['radosgw_address'] }}:{{ instance['radosgw_frontend_port'] }} weight 100 check
 {% endfor %}
 {% endfor %}