Creating managed instance groups

Traditionally, we have managed virtual machines individually. Instance groups let us manage a group of identical virtual machines as a single entity. These virtual machines are created from an instance template, like the one which we created in the previous tip. Now, if we have to make a change in instance configuration, that change would be applied to all the instances in the group.

How to do it…

Perhaps, the most important feature of an instance group is auto-scaling. In event of high resource requirements, the instance group can scale up to a predefined number automatically:

- name: create an instance group with autoscaling
  gce_mig:
    name: app-mig
    zone: "{{ zone }}"
    service_account_email: "{{ service_account_email }}"
    credentials_file: "{{ credentials_file }}"
    project_id: "{{ project_id }}"
    state: present
    size: 2
    named_ports:
    - name: http
      port: 80
    template: app-template
    autoscaling:
      enabled: yes
  ...