How to use Google Compute Python API to create custom machine type or instance with GPU? - google-cloud-platform

Question

I am just looking into using GCP for cloud computing stuff. So far I have been using AWS and the boto3 library and was trying to use the google python client API for launching instances.
So an example I came across was from their docs here. The instance machine type is specified as:
machine_type = "zones/%s/machineTypes/n1-standard-1" % zone
and then it passed to the configuration as:
config = {
'name': name,
'machineType': machine_type,
....
I wonder how does one go about specifying machines with GPU and custom RAM and processors etc. from the python API?

Answer 1

The Python API is basically a wrapper around the REST API, so in the example code you are using, the config object is being built using the same schema as would be passed in the insert request.
Reading that document shows that the guestAccelerators structure is the relevant one for GPUs.
Custom RAM and CPUs are more interesting. There is a format for specifying a custom machine type name (you can see it in the gcloud documentation for creating a machine type). The format is:
[GENERATION]custom-[NUMBER_OF_CPUs]-[RAM_IN_MB]
Generation refers to the "n1" or "n2" in the predefined names. For n1, this block is empty, for n2, the prefix is "n2-". That said, experimenting with gcloud seems to indicate that "n1-" as a prefix also works as you would expect.
So, for a 1 CPU n1 machine with 5GB of ram, it would be a custom-1-5120. This is what you would replace the n1-standard-1 in your example with.
You are, of course, subject to the limits of how to specify a custom machine such as the fact that RAM must be a multiple of 256MB.
Finally, there's a neat little feature at the bottom of the console "create instance" page:
Clicking on the relevant link will show you the exact REST object you need to create the machine you have defined in the console at that very moment, so it can be very useful to see how a particular parameter is used.

Answer 2

You can create a Compute Engine instance using the Compute Engine API. Specifically, we can use the insert API request. This accepts a JSON payload in a REST request that describes the desired VM instance that you desire. A full specification of the request is found in the docs. It includes:
machineType - specs of different (common) machines including CPUs and memory
disks - specs of disks to be added including size and type
guestAccelerators - specs for GPUs to add
many more options ...
One can also create a template description of the machine structure you want and simplify the creation of an instance by naming the template to use and thereby abstracting the configuration details out of code and into configuration.
Beyond using REST requests (which can be passed from a python), you also have the capability to create Compute Engines from:
GCP Console - web interface
gcloud - command line (which I suspect can also be driven from within Python)
Deployment Manager - configuration driven deployment which includes Python as a template language
Terraform - popular environment for creating Infrastructure as Code environments