edx-west: parameterize machine names in playbooks

Conflicts:
	playbooks/edx-west/prod-app.yml
	playbooks/edx-west/prod-worker.yml
	playbooks/edx-west/stage-app.yml
	playbooks/edx-west/stage-worker.yml

playbooks/edx-west/prod-app.yml

-# this gets all running prod webservers
+# This uses variable expansion so you can select machine(s) from the command line
+# using the -e flag.  See README for instructions on how to use.
+- hosts: ~tag_Name_{{machine}}_prod
+#
+# This alternative hits all running prod webservers.  Left here as an example.
 #- hosts: tag_environment_prod:&tag_function_webserver
-# or we can get subsets of them by name
-#- hosts: ~tag_Name_app(10|20)_prod
-- hosts: ~tag_Name_app(11|21)_prod
-## this is the test box
-#- hosts: ~tag_Name_app4_prod
-## you can also do security group, but don't do that
-#- hosts: security_group_edx-prod-EdxappServerSecurityGroup-NSKCQTMZIPQB
   sudo: True
   vars_prompt:
     - name: "migrate_db"

playbooks/edx-west/prod-worker.yml

-# For all util machines
-- hosts: tag_environment_prod:&tag_function_util
-# or we can get subsets of them by name
-#- hosts: ~tag_Name_util(1|2)_prod
+- name: Basic util setup on all hosts
+# This uses variable expansion so you can select machine(s) from the command line
+# using the -e flag.  See README for instructions on how to use.
+  hosts: ~tag_Name_{{machine}}_prod
+#
+# This alternative hits all running prod webservers.  Left here as an example.
+#  hosts: tag_environment_prod:&tag_function_util
   sudo: True
   vars:
     secure_dir: '../../../configuration-secure/ansible'

playbooks/edx-west/stage-app.yml

-- hosts: tag_environment_stage:&tag_function_webserver
-#- hosts: tag_Name_app1_stage
+# This uses variable expansion so you can select machine(s) from the command line
+# using the -e flag.  See README for instructions on how to use.
+- hosts: ~tag_Name_{{machine}}_stage
+#
+# This alternative hits all running prod webservers.  Left here as an example.
+#- hosts: tag_environment_stage:&tag_function_webserver
   sudo: True
   vars_prompt:
     - name: "migrate_db"

playbooks/edx-west/stage-worker.yml

-  # this gets all running stage util machiens
-- hosts: tag_environment_stage:&tag_function_util
-# or we can get subsets of them by name
-#- hosts: ~tag_Name_util(1|2)_stage
+---
+- name: Basic util setup on all hosts
+# This uses variable expansion so you can select machine(s) from the command line
+# using the -e flag.  See README for instructions on how to use.
+  hosts: ~tag_Name_{{machine}}_stage
+#
+# This alternative hits all running prod webservers.  Left here as an example.
+#  hosts: tag_environment_stage:&tag_function_util
   sudo: True
   vars:
     secure_dir: ../../../edx-secret/ansible