Make restart hander for pvcd sequential

roles/pvc/handlers/main.yml

@@ -19,7 +19,13 @@
     name: patroni
     state: restarted
 
+# Restart pvcd, but sequentially one-host-at-a-time with a 15s wait in between; this provides
+# plenty of time for the primary state to switch around without putting the cluster in a
+# no-primary state
 - name: restart pvcd
-  service:
-    name: pvcd
-    state: restarted
+  shell: systemctl restart pvcd && sleep 15
+  run_once: true
+  delegate_to: "{{ play_host }}"
+  with_items: "{{ play_hosts }}"
+  loop_control:
+    loop_var: play_host