Cloud-init

In some cases you may need to customize an instance at creation, before the build is started.

Overriding the default cloud-init file is an advanced feature and should be avoided unless absolutely necessary.

You can customize your instance configuration by providing a custom cloud-init file.

Templating is provided using golang template syntax, you can find more information here.

There are 2 variables available in the spec section of your pool file:

user_data field

The contents of the cloud-init file as a string in the pool.yml

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version: "1"
instances:
  - name: test_pool
    default: true
    type: amazon
    pool: 1    
    limit: 1 
    platform:
      os: linux
      arch: amd64
    spec:
      account:
        region: us-east-2
        access_key_id: XXXXXXXXXXXXXXXXXXXXX
        access_key_secret: XXXXXXXXXXXXXXXXXXXXX
      ami: ami-051197ce9cbb023ea
      size: t2.micro
      user_data: |
        #cloud-config
        apt:
          sources:
            docker.list:
              source: deb [arch={{ .Architecture }}] https://download.docker.com/linux/ubuntu $RELEASE stable
              keyid: 9DC858229FC7DD38854AE2D88D81803C0EBFCD88
        packages:
        - wget
        - docker-ce
        write_files:
        - path: {{ .CaCertPath }}
          permissions: '0600'
          encoding: b64
          content: {{ .CACert | base64  }}
        - path: {{ .CertPath }}
          permissions: '0600'
          encoding: b64
          content: {{ .TLSCert | base64 }}
        - path: {{ .KeyPath }}
          permissions: '0600'
          encoding: b64
          content: {{ .TLSKey | base64 }}
        runcmd:
        - 'wget "{{ .LiteEnginePath }}/lite-engine-{{ .Platform }}-{{ .Architecture }}" -O /usr/bin/lite-engine'
        - 'chmod 777 /usr/bin/lite-engine'
        - 'touch /root/.env'
        - 'touch /tmp/magic_lives_here'
        - '/usr/bin/lite-engine server --env-file /root/.env > /var/log/lite-engine.log 2>&1 &'

user_data_path field

The path to the cloud-init file as a string in the pool.yml

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version: "1"
instances:
  - name: test_pool
    default: true
    type: amazon
    pool: 1    
    limit: 1 
    platform:
      os: linux
      arch: amd64
    spec:
      account:
        region: us-east-2
        access_key_id: XXXXXXXXXXXXXXXXXXXXX
        access_key_secret: XXXXXXXXXXXXXXXXXXXXX
      ami: ami-051197ce9cbb023ea
      size: t2.micro
      user_data_path: /tmp/user-data.yml

You can see an example of a custom cloud-init template file here.