Auto-replace preemptible VMs

resizeInstanceGroup.js

const MANAGED_INSTANCE_GROUP_NAME = 'instance-group-2'
const MANAGED_INSTANCE_GROUP_ZONE = 'europe-north1-a'
const MANAGED_INSTANCE_GROUP_TEMPLATE_NAME_ONDEMAND = 'global/instanceTemplates/instance-template-ondemand-vms'
const MANAGED_INSTANCE_GROUP_TEMPLATE_NAME_PREEMTIBLE = 'global/instanceTemplates/instance-template-preemptible-vms-1'

const { auth, Compute } = require('google-auth-library')

const fns = {
    resize: async () => {
        const client = new Compute()
        const projectId = await auth.getProjectId()
        const apiUrl = `https://compute.googleapis.com/compute/v1/projects/${projectId}/zones/${MANAGED_INSTANCE_GROUP_ZONE}/instanceGroupManagers/${MANAGED_INSTANCE_GROUP_NAME}`

        return client.request(
            {
                url: apiUrl,
                method: 'PATCH',
                data: {
                    updatePolicy: {
                        type: 'PROACTIVE'
                    },
                    versions: [
                        {
                            instanceTemplate: MANAGED_INSTANCE_GROUP_TEMPLATE_NAME_ONDEMAND,
                            targetSize: {
                                fixed: 1
                            }
                        },
                        {
                            instanceTemplate: MANAGED_INSTANCE_GROUP_TEMPLATE_NAME_PREEMTIBLE
                        }
                    ]
                }
            }
        )
    }
}

const resizeInstanceGroup = async () => {
    const response = await fns.resize()
    console.log(response.data)
    
    return response.data
}

/**
 * Triggered from a message on a Cloud Pub/Sub topic.
 *
 * @param {!Object} event Event payload.
 * @param {!Object} context Metadata for the event.
 */
exports.resizeInstanceGroup = (event, context) => {
  resizeInstanceGroup().then(res => {
    console.log('Success!', res)
    process.exit(0)
  })
};