Update the apt cache after adding the repository.

tasks/cassandra-repo.yml

@@ -30,6 +30,12 @@
         signed_by: "{{ cassandra_deb_repo_key }}"
         state: present
         enabled: true
+      register: cassandra_repo
+    - name: cassandra-repo | Update the apt cache
+      ansible.builtin.apt:
+        update_cache: yes
+      when: cassandra_repo is changed
+
 
 - name: cassandra-repo | Manage the Cassandra repository on EL systems
   when: