It is possible that depending what the remote machine is where you are running an Ansible Playbook you want to run one action or the other.

For instance: depending on which version of CentOS you are using you would either want to use the binary docker or containerd to run docker.

I would go about accomplishing this in the following way:

- name: stat /var/lib/{{ docker_dir_centos7 }}
  stat:
    path: /var/lib/{{ docker_dir_centos7 }}
  register: var_lib_docker
  set_fact:
    docker_dir: "{{ docker_dir_centos7 }}"
  when: (ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "6") or
    (ansible_facts['distribution'] == "Debian" and ansible_facts['distribution_major_version'] == "7")

- name: stat /var/lib/{{ docker_dir_centos8 }}
  stat:
    path: /var/lib/{{ docker_dir_centos8 }}
  register: var_lib_docker
  set_fact:
    docker_dir: "{{ docker_dir_centos8 }}"
  when: ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "8"

After this I can use {{ docker_dir }} in the remaining steps to access docker binary.

For a more detailed reading on this check this out: https://raymii.org/s/tutorials/Ansible_-_Only_if_on_specific_distribution_or_distribution_version.html