Modify comments

playbooks/roles/hadoop_common/defaults/main.yml

@@ -11,10 +11,6 @@
 # Defaults for role hadoop_common
 # 
 
-#
-# vars are namespace with the module name.
-#
-
 HADOOP_COMMON_VERSION: 2.3.0
 HADOOP_COMMON_USER_HOME: /home/hadoop
 HADOOP_COMMON_HOME: "{{ HADOOP_COMMON_USER_HOME }}/hadoop"

playbooks/roles/hadoop_common/meta/main.yml

@@ -9,15 +9,6 @@
 #
 ##
 # Role includes for role hadoop_common
-# 
-# Example:
-#
-# dependencies:
-#   - {
-#   role: my_role 
-#   my_role_var0: "foo"
-#   my_role_var1: "bar"
-# }
 
 dependencies:
   - oraclejdk
\ No newline at end of file

playbooks/roles/hadoop_common/tasks/main.yml

@@ -13,12 +13,13 @@
 # 
 # Overview:
 # 
+# This role installs all hadoop services onto the machine. Note that this should
+# be used to configure all machines in a hadoop cluster. It does not perform
+# any role-specific actions such as formatting the namenode etc.
 #
 # Dependencies:
 #
-# 
-# Example play:
-#
+# oraclejdk: Not strictly required, but we tend to trust it more than openjdk.
 #
 
 - name: install system packages

playbooks/roles/hadoop_master/meta/main.yml

@@ -9,15 +9,6 @@
 #
 ##
 # Role includes for role hadoop_master
-# 
-# Example:
-#
-# dependencies:
-#   - {
-#   role: my_role 
-#   my_role_var0: "foo"
-#   my_role_var1: "bar"
-# }
 
 dependencies:
   - hadoop_common

playbooks/roles/hadoop_master/tasks/main.yml

@@ -13,12 +13,12 @@
 # 
 # Overview:
 # 
+# Configures the machine to be a Hadoop master node. This generally means that it will
+# run the HDFS name node and the yarn resource manager.
 #
 # Dependencies:
 #
-# 
-# Example play:
-#
+# hadoop_common: this role installs hadoop generically
 #
 
 - name: data directories created

playbooks/roles/hive/handlers/main.yml

----
-#
-# edX Configuration
-#
-# github:     https://github.com/edx/configuration
-# wiki:       https://github.com/edx/configuration/wiki
-# code style: https://github.com/edx/configuration/wiki/Ansible-Coding-Conventions
-# license:    https://github.com/edx/configuration/blob/master/LICENSE.TXT
-#
-#
-#
-# Handlers for role hive
-# 
-# Overview:
-# 
-#
-- name: notify me
-  debug: msg="stub handler"

playbooks/roles/hive/meta/main.yml

@@ -9,15 +9,6 @@
 #
 ##
 # Role includes for role hive
-# 
-# Example:
-#
-# dependencies:
-#   - {
-#   role: my_role 
-#   my_role_var0: "foo"
-#   my_role_var1: "bar"
-# }
 
 dependencies:
   - hadoop_common

playbooks/roles/hive/tasks/main.yml

@@ -13,13 +13,12 @@
 # 
 # Overview:
 # 
+# Install and configure Hive.
 #
 # Dependencies:
 #
-# 
-# Example play:
-#
-#
+# hadoop_common: Hive requires Hadoop to be installed to function properly.
+
 
 - name: check if downloaded and extracted
   stat: path={{ HIVE_HOME }}

playbooks/roles/sqoop/handlers/main.yml

----
-#
-# edX Configuration
-#
-# github:     https://github.com/edx/configuration
-# wiki:       https://github.com/edx/configuration/wiki
-# code style: https://github.com/edx/configuration/wiki/Ansible-Coding-Conventions
-# license:    https://github.com/edx/configuration/blob/master/LICENSE.TXT
-#
-#
-#
-# Handlers for role sqoop
-# 
-# Overview:
-# 
-#
-- name: notify me
-  debug: msg="stub handler"

playbooks/roles/sqoop/tasks/main.yml

@@ -13,13 +13,12 @@
 # 
 # Overview:
 # 
+# Install and configure Sqoop. This tool is used by the analytics stack to take database snapshots.
 #
 # Dependencies:
 #
-# 
-# Example play:
-#
-#
+# hadoop_common: Sqoop can distribute snapshotting work out to a cluster of workers, it uses Hadoop to do so.
+
 
 - name: check if downloaded and extracted
   stat: path={{ SQOOP_LIB }}/mysql-connector-java-{{ SQOOP_MYSQL_CONNECTOR_VERSION }}-bin.jar