guettli的答案是正确的，但你也可以把它缩短，只调用apt模块一次：

---
- hosts: all
  tasks:
    - name: Update and upgrade apt packages
      apt:
        name: nginx
        state: latest
        update_cache: yes
        upgrade: yes
    - name: start nginx
      service:
          name: nginx
          state: started

如果机器是几秒钟前安装的，那么您至少需要运行一次apt update。
您可以通过Ansible这样做：

---
- hosts: all
  tasks:
    - name: Update and upgrade apt packages
      apt:
        update_cache: yes
        upgrade: yes
    - name: ensure nginx is at the latest version
      apt: name=nginx state=latest
    - name: start nginx
      service:
          name: nginx
          state: started