--- - name: Count Docker containers on all hosts hosts: all gather_facts: no tasks: - name: Count running Docker containers on each host shell: "docker ps -q | wc -l" register: container_count changed_when: false - name: Display count for each host debug: msg: "Host {{ inventory_hostname }} has {{ container_count.stdout }} running Docker containers" - name: Aggregate total count run_once: true delegate_to: localhost vars: container_counts: "{{ hostvars | map(attribute='container_count.stdout') | map('int') | list }}" debug: msg: "Total running Docker containers across all hosts: {{ container_counts | sum }}"