Adding modularity to keepalived configuration

This patch introduces modularity into the default keepalived
configuration: Currently, keepalived uses a ping to check its
alive status. The IP was hard setted in the configuration file.

This patch introduces multiple variables:
- keepalived_ping_address
- keepalived_ping_count
- keepalived_ping_interval

The one probably used the most will be the
``keepalived_ping_address``. It's therefore listed in
``user_variables`` with the other keepalived variables.

Fixes-Bug: #1570420

Change-Id: Ic9a591fe739dd4ee3b0ad0130190e000404fb73a

doc/source/install-guide/configure-haproxy.rst

@@ -77,16 +77,26 @@ edit the ``/etc/openstack_deploy/user_variables.yml`` by setting:
 
    keepalived_use_latest_stable: True
 
-The HAProxy playbook makes use of the variable file
+The HAProxy playbook reads the ``vars/configs/keepalived_haproxy.yml``
-``vars/configs/keepalived_haproxy.yml``, and feeds its content
+variable file and provides its content to the keepalived role for
-to the keepalived role, for keepalived master and backup nodes.
+keepalived master and backup nodes.
 
-You can use your own variable file by setting
+Keepalived pings a public IP address to check its status. The default
-the path in your ``/etc/openstack_deploy/user_variables.yml``:
+address is ``193.0.14.129``. To change this default, for example to
+your gateway, set the ``keepalived_ping_address`` variable in the
+``user_variables.yml`` file.
+
+.. note:: The keepalived test works with IPv4 addresses only.
+
+You can define additional variables to adapt keepalived to the
+deployed environment. Refer to the ``user_variables.yml`` file for
+more information. Optionally, you can use your own variable file, as
+follows:
 
 .. code-block:: yaml
 
-   haproxy_keepalived_vars_file:
+   haproxy_keepalived_vars_file: /path/to/myvariablefile.yml
+
 
 Securing HAProxy communication with SSL certificates
 ####################################################

etc/openstack_deploy/user_variables.yml

@@ -167,6 +167,9 @@ verbose: false
 # haproxy_keepalived_priority_master:
 # haproxy_keepalived_priority_backup:
 
+# Keepalived default IP address used to check its alive status (IPv4 only)
+# keepalived_ping_address: "193.0.14.129"
+
 # All the previous variables are used in a var file, fed to the keepalived role.
 # To use another file to feed the role, override the following var:
 # haproxy_keepalived_vars_file: 'vars/configs/keepalived_haproxy.yml'

playbooks/vars/configs/keepalived_haproxy.yml

@@ -13,7 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-keepalived_sync_groups:
+keepalived_ping_address: "193.0.14.129"
+keepalived_ping_count: 1
+keepalived_ping_interval: 10
+
+keepalived_global_sync_groups:
   haproxy:
     instances:
       - external
@@ -28,8 +32,8 @@ keepalived_scripts:
   haproxy_check_script:
     check_script: "killall -0 haproxy"
   pingable_check_script:
-    check_script: "ping -c 1 193.0.14.129 1>&2"
+    check_script: "ping -c {{ keepalived_ping_count }} {{ keepalived_ping_address }} 1>&2"
-    interval: 10
+    interval: "{{ keepalived_ping_interval }}"
     fall: 2
     rise: 4