How do I start a Google Cloud instance with a container image from a Node.JS client? - node.js

Question

I want to start a vm instance with a container image from within a Google Cloud Function in Node.JS.
I can't figure out how to call the createVM function with a container image specified.
const [vm, operation] = await zone.createVM(vmName, {os: 'ubuntu'});
I don't see it anywhere in the documentation
https://googleapis.dev/nodejs/compute/latest/index.html

Answer 1

When creating the instance in the Google Cloud console, I was able to copy the equivalent REST command, take the JSON and paste it into the Google Cloud Compute Node.js SDK config.
const Compute = require('#google-cloud/compute');
// Creates a client
const compute = new Compute();
// Create a new VM using the latest OS image of your choice.
const zone = compute.zone('us-east1-d');
// The above object will auto-expand behind the scenes to something like the
// following. The Debian version may be different when you run the command.
//-
const config =
{
"kind": "compute#instance",
"name": "server",
"zone": "projects/projectName/zones/us-east1-d",
"machineType": "projects/projectName/zones/us-east1-d/machineTypes/f1-micro",
"displayDevice": {
"enableDisplay": false
},
"metadata": {
"kind": "compute#metadata",
"items": [
{
"key": "gce-container-declaration",
"value": "spec:\n containers:\n - name: game-server\n image: gcr.io/projectName/imageName\n stdin: false\n tty: false\n restartPolicy: Never\n\n# This container declaration format is not public API and may change without notice. Please\n# use gcloud command-line tool or Google Cloud Console to run Containers on Google Compute Engine."
},
{
"key": "google-logging-enabled",
"value": "true"
}
]
},
"tags": {
"items": [
"https-server"
]
},
"disks": [
{
... //Copied from Google Cloud console -> Compute Engine -> Create VM Instance -> copy equivalent REST command (at the bottom of the page)
]
};
//-
// If the callback is omitted, we'll return a Promise.
//-
zone.createVM('new-vm-name', config).then(function(data) {
const vm = data[0];
const operation = data[1];
const apiResponse = data[2];
res.status(200).send(apiResponse);
});

Answer 2

What I understand you want to end up with is a new GCP Compute Engine instance running the Container Optimized OS (COS) that runs Docker that creates a container instance from a repository hosted container image. To achieve this programatically, you are also wanting to use the Node.JS API.
The trick (for me) is to create an instance of the Compute Engine manually through the GCP Cloud Console. Once done, we can then login to the instance and retrieve the raw metadata by running:
wget --output-document=- --header="Metadata-Flavor: Google" --quiet http://metadata.google.internal/computeMetadata/v1/?recursive=true
What we get back is a JSON representation of that metadata. From here, we find that our actual goal in creating our desired Compute Engine through API is to create that Compute Engine using the standard API and then also define the metadata needed. It appears that the Container Optimized OS simply has a script/program which reads the metadata and uses that to run Docker.
When I examined data for a Container running in a Compute Engine, I found an attribute called:
attributes.gce-container-declaration
That contained:
"spec:\n containers:\n - name: instance-1\n image: nodered/node-red\n stdin: false\n tty: false\n restartPolicy: Always\n\n# This container declaration format is not public API and may change without notice. Please\n# use gcloud command-line tool or Google Cloud Console to run Containers on Google Compute Engine."
which is YAML and if we format it prettily we find:
spec:
containers:
- name: instance-1
image: nodered/node-red
stdin: false
tty: false
restartPolicy: Always
# This container declaration format is not public API and may change without notice. Please
# use gcloud command-line tool or Google Cloud Console to run Containers on Google Compute Engine.
And there we have it. To create a GCP Compute Engine hosting a container image, we would create a container image running the Container Optimized OS (eg. "image":"projects/cos-cloud/global/images/cos-stable-77-12371-114-0") and set the metadata to define the container to run.