Tweaks to make install run idempotent

roles/nova-controller/tasks/main.yml

@@ -1,11 +1,7 @@
 # Build and install a docker image for nova-controller.
 ---
-- name: pull docker image
-  docker_image:
-  name: webhost12.service.rug.nl/hpc/openstack-nova-service:latest
-  tags: pull
-
 - set_fact:
+    docker_image: webhost12.service.rug.nl/hpc/openstack-nova-service:latest
     env_vars: >
         -e "MY_IP={{ hostvars[groups['nova-controller'][0]]['ansible_default_ipv4']['address'] }}"
         -e "NOVA_USER=nova"
@@ -24,6 +20,12 @@
         -e "NEUTRON_PASSWORD=geheim"
         -e "NEUTRON_USER=neutron"
         -e "METADATA_SECRET=geheim"
+  tags: facts
+
+- name: pull docker image
+  docker_image:
+    name: "{{ docker_image }}"
+  tags: pull
 
 - name: install service file.
   template:
@@ -40,7 +42,7 @@
     /usr/bin/docker run --rm
     {{ env_vars }}
     --add-host=mariadb:{{ hostvars[groups['databases'][0]]['ansible_default_ipv4']['address'] }}
-    hpc/openstack-nova-service
+    {{ docker_image }}
     /etc/bootstrap.sh
   tags: bootstrap