diff --git a/IMPLEMENTATION.md b/IMPLEMENTATION.md
index 0f8b571..c071e93 100644
--- a/IMPLEMENTATION.md
+++ b/IMPLEMENTATION.md
@@ -190,7 +190,7 @@ After Docker install, re-SSH so the `docker` group membership takes effect.
 | App | Type | Hosts | Notes |
 |-----|------|-------|-------|
 | `company_site` | django (docker) | adama + roslin | active/active behind NPM |
-| `dta_service` | django (docker) | adama + roslin | active/active behind NPM |
+| `dta_service` | django (docker) | adama + roslin + ai-server-4080 | active/active behind NPM |
 | `dta_webapp` | node/vite static | adama + roslin | active/active; built to `/var/www/<env>_dta_webapp`, served by web-static nginx |
 
 Both environments (`beta`, `prod`) are deployed. Django apps use a **shared external
diff --git a/inventory/group_vars/all.yml b/inventory/group_vars/all.yml
index e5a697b..193b5e8 100644
--- a/inventory/group_vars/all.yml
+++ b/inventory/group_vars/all.yml
@@ -54,6 +54,10 @@ app_catalog:
     compose_file: docker-compose.prod.yml
     web_service: web
     migrate_cmd: "uv run python manage.py migrate --noinput"
+    # Pre-docker deploy used venv + systemd on each host; stop before compose up.
+    legacy_systemd_units:
+      beta: beta_dta_wsgi
+      prod: prod_dta_wsgi
   dta_webapp:
     type: node-static
     repo: "{{ git_base_url }}/Ditch_The_Agent/dta_webapp.git"
diff --git a/inventory/host_vars/ai-server-4080.yml b/inventory/host_vars/ai-server-4080.yml
index a708be9..4c440f1 100644
--- a/inventory/host_vars/ai-server-4080.yml
+++ b/inventory/host_vars/ai-server-4080.yml
@@ -13,7 +13,8 @@ act_runner_enabled: true
 # passphrase-less deploy key here instead.
 gitea_key_path: "/home/{{ admin_user }}/.ssh/gitea_deploy"
 
-# company_site prod runs here for side testing.
+# company_site + dta_webapp + dta_service for side testing and active/active.
+# Ports MUST match adama/roslin so NPM can balance all three upstreams.
 host_apps:
   - { name: company_site, env: prod, port: 8000 }
   - { name: dta_webapp, env: prod, port: 8080 }
diff --git a/roles/app-deploy/tasks/django.yml b/roles/app-deploy/tasks/django.yml
index a14dc53..91d3a84 100644
--- a/roles/app-deploy/tasks/django.yml
+++ b/roles/app-deploy/tasks/django.yml
@@ -76,6 +76,30 @@
   become_user: "{{ admin_user }}"
   changed_when: true
 
+- name: "django[{{ _project }}] legacy systemd unit"
+  ansible.builtin.set_fact:
+    _legacy_systemd: "{{ _spec.legacy_systemd_units[app_item.env] | default('') }}"
+  when: _spec.legacy_systemd_units is defined
+
+- name: "django[{{ _project }}] probe legacy systemd unit"
+  ansible.builtin.command:
+    cmd: systemctl list-unit-files {{ _legacy_systemd }}.service --no-legend
+  register: _legacy_systemd_probe
+  changed_when: false
+  failed_when: false
+  become: true
+  when: _legacy_systemd | default('') | length > 0
+
+- name: "django[{{ _project }}] stop legacy systemd unit"
+  ansible.builtin.systemd:
+    name: "{{ _legacy_systemd }}"
+    state: stopped
+    enabled: false
+  become: true
+  when:
+    - _legacy_systemd | default('') | length > 0
+    - _legacy_systemd_probe.stdout | default('') | length > 0
+
 - name: "django[{{ _project }}] start containers"
   ansible.builtin.command:
     cmd: "docker compose -f {{ _spec.compose_file }} --env-file .env up -d --remove-orphans"