ITOPSENG-164 Save the binary to shared home adding a locking mechanism to avoid potential race condition. This also allows downloading of old binaries once no longer available to download

roles/product_install/tasks/main.yml

@@ -116,6 +116,7 @@
     - "{{ atl_product_home }}"
     - "{{ atl_product_installation_versioned }}"
     - "{{ atl_product_version_cache_dir }}"
+    - "{{ atl_product_home_shared_download_dir }}"
   changed_when: false  # For Molecule idempotence check
 
 # At this point atl_product_version should be set, cache if necessary.
@@ -125,17 +126,75 @@
     dest: "{{ atl_product_version_cache }}"
     force: true
 
+# For the first run a temp binary should be downloaded but moved to shared home to ensure all subsequent nodes have access
+# to the same specific version binary.
+# To prevent a race condition with multiple downloads at the same time a directory is used as a lockfile (atomic operation).
 
-# Note: We don't the cache binary in the shared drive to the complexity
-# around download race-conditions if multiple nodes are starting at
-# the same time. When downloading from product-downloads.atlassian.com
-# (which is a CDN) takes seconds anyway.
-- name: Fetch product installer
-  get_url:
-    url: "{{ atl_product_download_url }}"
-    dest: "{{ atl_product_download }}"
-    mode: 0755
-    force: false
+- name: Assume temp binary should be downloaded
+  set_fact:
+    download_binary: yes
+
+# Check for product installer in home_shared and lockdir to determine if it needs to be downloaded again.
+- name: Check download lock directory exists
+  stat:
+    path: "{{ atl_product_home_shared_download_lockdir }}"
+  register: download_lockdir
+
+- name: Check for presence of product installer in home_shared
+  stat:
+    path: "{{ atl_product_home_shared_download }}"
+  register: home_shared_downloaded
+
+# If binary exists and lockdir exists use this binary instead
+- name: Check Lock Directory and binary exists on shared_home
+  set_fact:
+    download_binary: no
+  when:
+  - home_shared_downloaded.stat.exists
+  - download_lockdir.stat.isdir is defined
+  - download_lockdir.stat.isdir
+
+# If the binary was never installed, download it
+- name: "Download product installer and move to shared directory"
+  block:
+
+  - name: Fetch product installer 
+    get_url:
+      url: "{{ atl_product_download_url }}"
+      dest: "{{ atl_product_download }}"
+      mode: 0755
+      force: false
+    register: atl_product_downloaded
+
+  - name: Remove lockdir to prevent nodes relying on binary when copying
+    file:
+      path: "{{ atl_product_home_shared_download_lockdir }}"
+      state: absent
+    when: atl_product_downloaded is succeeded
+    register: lockdir_removed
+
+  - name: Copy temp installer to home_shared
+    copy:
+      src: "{{ atl_product_download }}"
+      dest: "{{ atl_product_home_shared_download }}"
+      remote_src: yes
+    when: lockdir_removed is succeeded
+    register: copied
+
+  - name: Delete old temp installer
+    file:
+      path: "{{ atl_product_download }}"
+      state: absent
+    when: copied is succeeded
+    register: temp_deleted
+
+  - name: Create lockdir once product installer downloaded and moved
+    file:
+      path: "{{ atl_product_home_shared_download_lockdir }}"
+      state: directory
+    when: temp_deleted is succeeded
+
+  when: download_binary
 
 - name: Unpack the downloaded application depending on format
   include_tasks: "unpack_{{ atl_download_format }}.yml"