Only install to virtual environment

Remove all tasks and variables related to toggling between installation
of rally inside or outside of a Python virtual environment.
Installing within a venv is now the only supported deployment.

Additionally, a few changes have been made to make the creation of the
venv more resistant to interruptions during a run of the role.
* unarchiving a pre-built venv will now also occur when the venv
  directory is created, not only after being downloaded
* virtualenv-tools is run against both pre-built and non pre-built venvs
  to account for interruptions during or prior to unarchiving

Change-Id: I815dff623fce1440a5d60f64bf69f4f563371998
Implements: blueprint only-install-venvs

defaults/main.yml

@@ -31,15 +31,7 @@ rally_developer_constraints:
 
 # Name of the virtual env to deploy into
 rally_venv_tag: untagged
-rally_venv_bin: "/openstack/venvs/rally-{{ rally_venv_tag }}/bin"
-
-# Set this to enable or disable installing in a venv
-rally_venv_enabled: true
-
-# The bin path defaults to the venv path however if installation in a
-# venv is disabled the bin path will be dynamically set based on the
-# system path used when the installing.
-rally_bin: "{{ rally_venv_bin }}"
+rally_bin: "/openstack/venvs/rally-{{ rally_venv_tag }}/bin"
 
 rally_venv_download_url: http://127.0.0.1/venvs/untagged/ubuntu/rally.tgz
 
@@ -58,4 +50,4 @@ rally_pip_packages:
   - pymysql
   - rally
 
-rally_config_overrides: {}
+rally_config_overrides: {}

releasenotes/notes/os_rally-install-venv-71cbd1f6ce4fd983.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - Installation of rally and its dependent pip packages will now only
+    occur within a Python virtual environment. The ``rally_venv_bin``,
+    ``rally_venv_enabled`` variables have been removed.

tasks/install.yml

@@ -83,7 +83,6 @@
     get_md5: False
   when:
     - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
   register: local_venv_stat
   tags:
     - rally-install
@@ -95,7 +94,6 @@
     return_content: True
   when:
     - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
   register: remote_venv_checksum
   tags:
     - rally-install
@@ -115,7 +113,6 @@
   register: get_venv
   when:
     - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
     - (local_venv_stat.stat.exists == False or
         {{ local_venv_stat.stat.checksum is defined and local_venv_stat.stat.checksum != remote_venv_checksum.content | trim }})
   tags:
@@ -125,17 +122,15 @@
 - name: Set rally get_venv fact
   set_fact:
     rally_get_venv: "{{ get_venv }}"
-  when: rally_venv_enabled | bool
   tags:
     - rally-install
     - rally-pip-packages
 
 - name: Remove existing venv
   file:
-    path: "{{ rally_venv_bin | dirname }}"
+    path: "{{ rally_bin | dirname }}"
     state: absent
   when:
-    - rally_venv_enabled | bool
     - rally_get_venv | changed
   tags:
     - rally-install
@@ -143,12 +138,9 @@
 
 - name: Create rally venv dir
   file:
-    path: "{{ rally_venv_bin | dirname }}"
+    path: "{{ rally_bin | dirname }}"
     state: directory
-  when:
-    - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
-    - rally_get_venv | changed
+  register: rally_venv_dir
   tags:
     - rally-install
     - rally-pip-packages
@@ -156,32 +148,20 @@
 - name: Unarchive pre-built venv
   unarchive:
     src: "/var/cache/{{ rally_venv_download_url | basename }}"
-    dest: "{{ rally_venv_bin | dirname }}"
+    dest: "{{ rally_bin | dirname }}"
     copy: "no"
   when:
     - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
-    - rally_get_venv | changed
+    - rally_get_venv | changed or rally_venv_dir | changed
   tags:
     - rally-install
     - rally-pip-packages
 
-- name: Update virtualenv path
-  command: >
-    virtualenv-tools --update-path=auto {{ rally_venv_bin | dirname }}
-  when:
-    - not rally_developer_mode | bool
-    - rally_venv_enabled | bool
-    - rally_get_venv | success
-  tags:
-    - rally-install
-    - rally-pip-packages
-
-- name: Install pip packages (venv)
+- name: Install pip packages
   pip:
     name: "{{ item }}"
     state: latest
-    virtualenv: "{{ rally_venv_bin | dirname }}"
+    virtualenv: "{{ rally_bin | dirname }}"
     virtualenv_site_packages: "no"
     extra_args: "{{ pip_install_options_fact }}"
   register: install_packages
@@ -190,25 +170,18 @@
   delay: 2
   with_items: rally_pip_packages
   when:
-    - rally_venv_enabled | bool
     - rally_get_venv | failed or rally_developer_mode | bool
   tags:
     - rally-install
     - rally-pip-packages
 
-- name: Install pip packages (no venv)
-  pip:
-    name: "{{ item }}"
-    state: latest
-    extra_args: "{{ pip_install_options_fact }}"
-  register: install_packages
-  until: install_packages|success
-  retries: 5
-  delay: 2
-  with_items: rally_pip_packages
+- name: Update virtualenv path
+  command: >
+    virtualenv-tools --update-path=auto {{ rally_bin | dirname }}
   when:
-    - not rally_venv_enabled | bool
     - not rally_developer_mode | bool
+    - rally_get_venv | success
   tags:
     - rally-install
     - rally-pip-packages
+