Only setup backup when rsnapshot is configured, don't use password for root auth

Mysql doesn't need a root password to authenticate root locally. And without rsnapshot installed, configuring rsnapshot config doesn't work.

postgres/tasks/main.yml

@@ -36,23 +36,26 @@
     state: started
     enabled: true
 
-- name: ensure we have our postgres backup script
-  copy:
-    src: "pgbackup{{ '-bullseye' if ansible_distribution_major_version|int(default=99) > 10 else '' }}.sh"
-    dest: /usr/local/bin/pgbackup.sh
-    owner: root
-    group: root
-    mode: '0755'
+- name: configure snapshots
+  when: '"servers_rsnapshot" in group_names'
+  block:
+    - name: ensure we have our postgres backup script
+      copy:
+        src: "pgbackup{{ '-bullseye' if ansible_distribution_major_version|int(default=99) > 10 else '' }}.sh"
+        dest: /usr/local/bin/pgbackup.sh
+        owner: root
+        group: root
+        mode: '0755'
 
-- name: ensure we have our rsnapshot config
-  copy:
-    src: rsnapshot.conf
-    dest: /etc/rsnapshot.d/postgres.conf
-    owner: root
-    group: root
-    mode: '0644'
+    - name: ensure we have our rsnapshot config
+      copy:
+        src: rsnapshot.conf
+        dest: /etc/rsnapshot.d/postgres.conf
+        owner: root
+        group: root
+        mode: '0644'
 
-- name: remove obsolete crontab
-  file:
-    path: /etc/cron.d/postgres-snapshot
-    state: absent
+    - name: remove obsolete crontab
+      file:
+        path: /etc/cron.d/postgres-snapshot
+        state: absent