環境

Ansible 2.7.10
Amazon Linux 2 AMI (HVM), SSD Volume Type, ami-0c3fd0f5d33134a76

Playbook

datadog/tasks/main.yml

---
- name: enable datadog repo
  copy: src=../files/datadog.repo dest=/etc/yum.repos.d/datadog.repo
  become: yes

- name: install datadog
  yum:
    name: datadog-agent
    update_cache: yes
    state: present
  become: yes

- name: copy datadog config
  copy:
    src: /etc/datadog-agent/datadog.yaml.example
    dest: /etc/datadog-agent/datadog.yaml
    remote_src: yes
  become: yes

- name: update datadog config
  lineinfile:
    path: /etc/datadog-agent/datadog.yaml
    regexp: '^api_key:.*'
    line: "api_key: (API KEY)"
    remote_src: yes
  become: yes

- name: restart datadog
  systemd:
    name: datadog-agent.service
    state: restarted
  become: yes

datadog/files/datadog.repo

[datadog]
name = Datadog, Inc.
baseurl = https://yum.datadoghq.com/stable/6/x86_64/
enabled=1
gpgcheck=1
gpgkey=https://yum.datadoghq.com/DATADOG_RPM_KEY.public

参考

Setup | Datadog

追記

頑張って書かなくてもAnsible Galaxyあった。

Setup | Datadog