migrate opendistro host data to opensearch automatically

Author: sjpb

ansible/adhoc/migrate-opendistro.yml

@@ -1,5 +1,15 @@
 ---
 
+- name: Check for existing opendistro service
+  stat:
+    path: /etc/systemd/system/opendistro.service
+  register: _opensearch_opendistro_service
+
+- name: Migrate opendistro data
+  import_tasks:
+    file: migrate-opendistro.yml
+  when: _opensearch_opendistro_service.stat.exists
+
 - name: Increase maximum number of virtual memory maps
   # see https://opensearch.org/docs/2.0/opensearch/install/important-settings/
   ansible.posix.sysctl:

ansible/roles/opensearch/tasks/main.yml

@@ -1,39 +1,28 @@
+# Migrate data from existing containerised opendistro v1.12.0 to containerised opensearch 2.1.0.
+#
 # This relies on:
-# - open{distro,search}_podman_user being the same
-# - opendistro and opensearch hosts being the same
+# - Both opendistro and opensearch using host directories for data. See `_default_opendistro_data_path` below
+# - Pre-upgrade group `opendistro` and current group `opensearch` containing the same host.
+#
+# NB: If `opendistro_data_path` was set to something non-default it MUST be set again in the `opensearch` group_vars,
+# as the `opendistro` group will not exist in the groups.
 
-# NB: This deliberately does not remove the opendistro podman volume - do that manually once happy.
+# NB: This deliberately does not remove the opendistro data - this could be done manually if required.
 
 - name: Stop opendistro
   ansible.builtin.systemd:
     name: opendistro.service
     state: stopped
     enabled: false
-  become: yes
-    
-- name: Export opendistro volume
-  ansible.builtin.shell:
-    cmd: podman volume export opendistro --output /tmp/opendistro_volume.tar
-    creates: /tmp/opendistro_volume.tar
-  become: yes
-  become_user: "{{ opensearch_podman_user }}"
 
-- name: Make opensearch data directory
-  file:
-    path: "{{ opensearch_data_path }}"
-    state: directory
+- name: Copy opendistro data directory
+  ansible.builtin.copy:
+    remote_src: true
+    src: "{{ opendistro_data_path | default(_default_opendistro_data_path) }}"
+    dest: "{{ opensearch_data_path | dirname }}/" # copying a directory, so need to specify the parent for destination
     owner: "{{ opensearch_podman_user }}"
     group: "{{ opensearch_podman_user }}"
-  become: yes
-  become_user: "{{ opensearch_podman_user }}"
-
-- name: Unpack opendistro volume
-  ansible.builtin.unarchive:
-    remote_src: yes
-    src: /tmp/opendistro_volume.tar
-    dest: "{{ opensearch_data_path }}"
-    owner: "{{ opensearch_podman_user }}"
-    group: "{{ opensearch_podman_user }}"
-    list_files: yes
-  become: yes
-  become_user: "{{ opensearch_podman_user }}"
+    mode: 0770
+  vars:
+    # from environments/common/inventory/group_vars/all/opendistro.yml:
+    _default_opendistro_data_path: "{{ appliances_state_dir | default('/usr/share') }}/elasticsearch/data"