How to authenticate to a GKE cluster without using the gcloud CLI - kubernetes

Question

I've got a container inside a GKE cluster and I want it to be able to talk to the Kubernetes API of another GKE cluster to list some resources there.
This works well if run the following command in a separate container to proxy the connection for me:
gcloud container clusters get-credentials MY_CLUSTER --region MY_REGION --project MY_PROJECT; kubectl --context MY_CONTEXT proxy --port=8001 --v=10
But this requires me to run a separate container that, due to the size of the gcloud cli is more than 1GB big.
Ideally I would like to talk directly from my primary container to the other GKE cluster. But I can't figure out how to figure out the IP address and set-up the authentication required for the connection.
I've seen a few questions:
How to Authenticate GKE Cluster on Kubernetes API Server using its Java client library
Is there a golang sdk equivalent of "gcloud container clusters get-credentials"
But it's still not really clear to me if/how this would work with the Java libraries, if at all possible.
Ideally I would write something like this.
var info = gkeClient.GetClusterInformation(...);
var auth = gkeClient.getAuthentication(info);
...
// using the io.fabric8.kubernetes.client.ConfigBuilder / DefaultKubernetesClient
var config = new ConfigBuilder().withMasterUrl(inf.url())
.withNamespace(null)
// certificate or other autentication mechanishm
.build();
return new DefaultKubernetesClient(config);
Does that make sense, is something like that possible?

Answer 1

There are multiple ways to connect to your cluster without using the gcloud cli, since you are trying to access the cluster from another cluster within the cloud you can use the workload identity authentication mechanism. Workload Identity is the recommended way for your workloads running on Google Kubernetes Engine (GKE) to access Google Cloud services in a secure and manageable way. For more information refer to this official document. Here they have detailed a step by step procedure for configuring workload identity and provided reference links for code libraries.
This is drafted based on information provided in google official documentation.