老师，你好！
在实战案例中，你的playbook如下，我不是很理解，这里只是安装的nginx的yum源，并没有哪个步骤是安装nginx，后面又直接重启nginx服务了。不知道是不是我理解有问题，麻烦老师指教。

- name: Disable system firewall
  service: name=firewalld state=stopped

- name: Disable SELINUX
  selinux: state=disabled

- name: setup nginx yum source
  yum: pkg=epel-release state=latest

- name: write then nginx config file
  template: src=roles/nginx/templates/nginx.conf.j2 dest=/etc/nginx/nginx.conf

- name: create nginx root folder
  file: 'path={{ root }} state=directory owner={{ user }} group={{ user }} mode=0755'

- name: copy index.html to remote
  copy: 'remote_src=no src=roles/nginx/files/index.html dest=/www/index.html mode=0755'

- name: restart nginx service
  service: name=nginx state=restarted

- name: run the health check locally
  shell: "sh roles/nginx/files/health_check.sh {{ server_name }}"
  delegate_to: localhost
  register: health_status