defaulting common_hostname to empty string

also extra vars overrides developer sandbox defaults

playbooks/roles/common/defaults/main.yml

@@ -33,7 +33,7 @@ COMMON_UBUNTU_APT_KEYSERVER: "http://keyserver.ubuntu.com/pks/lookup?op=get&fing
 # do not include http/https
 COMMON_GIT_MIRROR: 'github.com'
 # override this var to set a different hostname
-COMMON_HOSTNAME: !!null
+COMMON_HOSTNAME: ""
 
 # Set to true to customize DNS search domains
 COMMON_CUSTOM_DHCLIENT_CONFIG: false

playbooks/roles/common/tasks/main.yml

@@ -95,18 +95,18 @@
 
 - name: update /etc/hosts
   template: src=hosts.j2 dest=/etc/hosts
-  when: COMMON_HOSTNAME
+  when: COMMON_HOSTNAME|length > 0
   register: etc_hosts
 
 - name: update /etc/hostname
   template: src=hostname.j2 dest=/etc/hostname
-  when: COMMON_HOSTNAME
+  when: COMMON_HOSTNAME|length > 0
   register: etc_hostname
 
 - name: run hostname
   shell: >
     hostname -F /etc/hostname
-  when: COMMON_HOSTNAME and (etc_hosts.changed or etc_hostname.changed)
+  when: COMMON_HOSTNAME|length >0 and (etc_hosts.changed or etc_hostname.changed)
 
 - name: update /etc/dhcp/dhclient.conf
   template: src=etc/dhcp/dhclient.conf.j2 dest=/etc/dhcp/dhclient.conf

util/jenkins/ansible-provision.sh

@@ -57,7 +57,7 @@ extra_var_arg="-e@${extra_vars_file}"
 if [[ $edx_internal == "true" ]]; then
     # if this is a an edx server include
     # the secret var file
-    extra_var_arg="-e@${extra_vars_file} -e@${WORKSPACE}/configuration-secure/ansible/vars/developer-sandbox.yml"
+    extra_var_arg="-e@${WORKSPACE}/configuration-secure/ansible/vars/developer-sandbox.yml -e@${extra_vars_file}"
 fi
 
 if [[ -z $region ]]; then