接下來是看要如何利用 Ansible 部屬我們的程式

我們一樣會寫 Ansible Playbook，流程大概是

• 更新系統
• 安裝 Node.JS 和 NPM
• 安裝我們的程式

先看我們的 Playbook 和 roles

# deploy.yml
---
- hosts: all
  roles:
    - apt_upgrade
    - install_nodejs
    - install_app

# roles/apt_upgrade/tasks/main.yml
---
- name: Perform 'apt update'
  apt:
    update_cache: yes
  tags:
    - apt

- name: Perform 'apt upgrade'
  apt:
    package: '*'
    state: latest
  tags:
    - apt

# roles/install_nodejs/tasks/main.yml
---

- name: Use apt to install nodejs & npm
  apt:
    pkg:
      - nodejs
      - npm
  tags:
    - nodejs

---
- name: Create dir /app
  file:
    path: /app
    owner: root
    group: root
    mode: '0755'
    state: directory
  tags:
    - app
- name: Copy our app into folder
  copy:
    src: ../../../../app/index.js
    dest: /app/index.js
    owner: root
    group: root
    mode: '0644'
  tags:
    - app
- name: Run npm install in the folder
  shell: npm i express
  args:
    chdir: /app
- name: Install systemd service file
  copy:
    src: nodeapp.service
    dest: /etc/systemd/system/nodeapp.service
    owner: root
    group: root
    mode: '0644'
  tags:
    - app
- name: Reload systemd daemon
  systemd:
    daemon_reload: yes
  tags:
    - app
- name: Enable nodeapp service
  systemd:
    name: nodeapp
    state: started
    enabled: yes
  tags:
    - app

# roles/install_app/files/nodeapp.service
[Unit]
Description=Node App
After=network.target

[Service]
Type=simple
ExecStart=/usr/bin/node /app/index.js
Restart=on-failure

[Install]
WantedBy=multi-user.target

我們接下來要在 lxc.tf 裡加入部署選項
我們要把我們的 SSH Key 放進去，同時也要放部署的指令
大概會像這樣

ssh_public_keys = "<YOUR_SSH_KEY>"
  provisioner "local-exec" {
    command = "sleep 30; ansible-playbook -u root -i '${var.lxc_ip},' deploy.yml;"
  }

最後，當我們執行 terraform apply 的時候，就能看到 Ansible 把我們的 app 部署進去了
執行結果大概像這樣

這樣我們就有辦法利用工具來幫助我們部署、管理機器了
明天講監控的部分