Simplify site.yml and allow parallelization of 'common' role tasks, and update to new pre_task/post_task syntax for rolling update.

lamp_haproxy/db.yml

@@ -1,12 +0,0 @@
----
-# This playbook deploys MySQL and configures the database on the db node(s)
-
-# fetch monitoring facts for iptables rules
-- hosts: monitoring
-  tasks:
-
-- hosts: dbservers
-  user: root
-  roles:
-  - common
-  - db

lamp_haproxy/haproxy.yml

@@ -1,12 +0,0 @@
----
-# Playbook for HAProxy operations
-
-# fetch monitoring facts for iptables rules
-- hosts: monitoring
-  tasks:
-
-- hosts: lbservers
-  user: root
-  roles:
-  - common
-  - haproxy

lamp_haproxy/nagios.yml

@@ -1,13 +0,0 @@
----
-# This playbook configures the monitoring node 
-
-# trigger fact-gathering for all hosts
-- hosts: all
-  tasks:
-
-- hosts: monitoring
-  user: root
-  roles:
-  - common
-  - base-apache
-  - nagios

lamp_haproxy/rolling_update.yml

@@ -1,14 +1,22 @@
 ---
-# This playbook does a rolling update of the code for all webservers serially (one at a time).
+# This playbook does a rolling update for all webservers serially (one at a time).
 # Change the value of serial: to adjust the number of server to be updated.
-# This playbook also takes the webapp_version variable to specify which git version
-# of the test webapp to deploy.
+#
+# The three roles that apply to the webserver hosts will be applied: common,
+# base-apache, and web. So any changes to configuration, package updates, etc,
+# will be applied as part of the rolling update process.
+# 
+
+# gather facts from monitoring nodes for iptables rules
+- hosts: monitoring
+  tasks:
 
 - hosts: webservers
   user: root
   serial: 1
-  tasks:
   
+  # These are the tasks to run before applying updates:
+  pre_tasks:
   - name: disable nagios alerts for this host webserver service
     nagios: action=disable_alerts host=$ansible_hostname services=webserver
     delegate_to: $item
@@ -19,12 +27,13 @@
     delegate_to: $item
     with_items: ${groups.lbservers}
 
-  - name: Remove the code from server
-    command: rm -rf /var/www/html/*
-
-  - name: Copy the code from repository
-    git: repo=${repository} version=${webapp_version} dest=/var/www/html/
+  roles:
+  - common
+  - base-apache
+  - web
 
+  # These tasks run after the roles:
+  post_tasks:
   - name: Enable the server in haproxy
     shell: echo "enable server myapplb/${ansible_hostname}" | socat stdio /var/lib/haproxy/stats
     delegate_to: $item

lamp_haproxy/site.yml

@@ -1,7 +1,36 @@
 ---
-#This Playbook deploys the whole application stack in this site.  
+# This playbook deploys the whole application stack in this site.  
 
-- include: db.yml
-- include: web.yml
-- include: haproxy.yml
-- include: nagios.yml
+# Apply common configuration to all hosts
+- hosts: all
+  roles:
+  - common
+
+# Configure and deploy database servers.
+- hosts: dbservers
+  user: root
+  roles:
+  - db
+
+# Configure and deploy the web servers. Note that we include two roles here, 
+# the 'base-apache' role which simply sets up Apache, and 'web' which includes
+# our example web application.
+- hosts: webservers
+  user: root
+
+  roles:
+  - base-apache
+  - web
+
+# Configure and deploy the load balancer(s).
+- hosts: lbservers
+  user: root
+  roles:
+  - haproxy
+
+# Configure and deploy the Nagios monitoring node(s).
+- hosts: monitoring
+  user: root
+  roles:
+  - base-apache
+  - nagios

lamp_haproxy/web.yml

@@ -1,14 +0,0 @@
----
-# This playbook deploys the webservers with httpd and the code.
-
-# fetch monitoring facts for iptables rules
-- hosts: monitoring
-  tasks:
-
-- hosts: webservers
-  user: root
-
-  roles:
-  - common
-  - base-apache
-  - web