create COMMON_BASE_DIR

playbooks/roles/common/defaults/main.yml

@@ -2,14 +2,16 @@
 # Override these variables
 # to change the base directory
 # where edX is installed
-COMMON_DATA_DIR: /edx/var
-COMMON_APP_DIR: /edx/app
+
+COMMON_BASE_DIR: /edx
+COMMON_DATA_DIR: "{{ COMMON_BASE_DIR}}/var"
+COMMON_APP_DIR: "{{ COMMON_BASE_DIR}}/app"
 COMMON_LOG_DIR: "{{ COMMON_DATA_DIR }}/log"
 
 # these directories contain
 # symlinks for convenience
-COMMON_BIN_DIR: /edx/bin
-COMMON_CFG_DIR: /edx/etc
+COMMON_BIN_DIR: "{{ COMMON_BASE_DIR }}/bin"
+COMMON_CFG_DIR: "{{ COMMON_BASE_DIR }}/etc"
 
 COMMON_ENV_NAME: 'default_env'
 COMMON_ENV_TYPE: 'default_type'