Kubernetes Federation: Cluster Creation, Configuration, and Joining

gcloud container clusters create gce-europe-west1-b --project=${FED\_PROJECT} --zone=europe-west1-b --scopes cloud-platform,storage-ro,logging-write,monitoring-write,service-control,service-management,https://www.googleapis.com/auth/ndev.clouddns.readwrite gcloud container clusters create gce-asia-east1-a --project=${FED\_PROJECT} --zone=asia-east1-a --scopes cloud-platform,storage-ro,logging-write,monitoring-write,service-control,service-management,https://www.googleapis.com/auth/ndev.clouddns.readwrite ``` The next step is fetching kubectl configuration with gcloud -q container clusters get-credentials (2-getcredentials.sh). The configurations will be used to indicate the current context for kubectl commands. ``` $ cat 2-getcredentials.sh && . 2-getcredentials.sh gcloud -q container clusters get-credentials gce-us-east1-b --zone=us-east1-b --project=${FED\_PROJECT} gcloud -q container clusters get-credentials gce-europe-west1-b --zone=europe-west1-b --project=${FED\_PROJECT} gcloud -q container clusters get-credentials gce-asia-east1-a --zone=asia-east1-a --project=${FED\_PROJECT} ``` Let’s verify the setup: ``` $ kubectl config get-contexts CURRENT NAME CLUSTER AUTHINFO NAMESPACE \* gke\_container-solutions\_europe-west1-b\_gce-europe-west1-b gke\_container-solutions\_europe-west1-b\_gce-europe-west1-b gke\_container-solutions\_europe-west1-b\_gce-europe-west1-b gke\_container-solutions\_us-east1-b\_gce-us-east1-b gke\_container-solutions\_us-east1-b\_gce-us-east1-b gke\_container-solutions\_us-east1-b\_gce-us-east1-b gke\_container-solutions\_asia-east1-a\_gce-asia-east1-a gke\_container-solutions\_asia-east1-a\_gce-asia-east1-a gke\_container-solutions\_asia-east1-a\_gce-asia-east1-a ``` We have 3 clusters. One, indicated by the FED\_HOST\_CLUSTER environment variable, will be used to run the federation plane. For this, we will use the kubefed init federation command (3-initfed.sh). ``` $ cat 3-initfed.sh && . 3-initfed.sh kubefed init federation --host-cluster-context=gke\_${FED\_PROJECT}\_${FED\_HOST\_CLUSTER}\_gce-${FED\_HOST\_CLUSTER} --dns-zone-name=${FED\_DNS\_ZONE} ``` You will notice that after executing the above command, a new kubectl context has appeared: ``` $ kubectl config get-contexts CURRENT NAME CLUSTER AUTHINFO NAMESPACE ... federation federation ``` The federation context will become our administration entry point. Now it’s time to join clusters (4-joinfed.sh): ``` $ cat 4-joinfed.sh && . 4-joinfed.sh kubefed --context=federation join cluster-europe-west1-b --cluster-context=gke\_${FED\_PROJECT}\_europe-west1-b\_gce-europe-west1-b --host-cluster-context=gke\_${FED\_PROJECT}\_${FED\_HOST\_CLUSTER}\_gce-${FED\_HOST\_CLUSTER} kubefed --context=federation join cluster-asia-east1-a --cluster-context=gke\_${FED\_PROJECT}\_asia-east1-a\_gce-asia-east1-a --host-cluster-context=gke\_${FED\_PROJECT}\_${FED\_HOST\_CLUSTER}\_gce-${FED\_HOST\_CLUSTER} kubefed --context=federation join cluster-us-east1-b --cluster-context=gke\_${FED\_PROJECT}\_us-east1-b\_gce-us-east1-b --host-cluster-context=gke\_${FED\_PROJECT}\_${FED\_HOST\_CLUSTER}\_gce-${FED\_HOST\_CLUSTER} ``` Note that cluster gce-us-east1-b is used here to run the federation control plane and also to work as a worker cluster. This circular dependency helps to use resources more efficiently and it can be verified by using the kubectl --context=federation get clusters command:

This section outlines the process of creating GKE clusters in Europe and Asia, then fetching kubectl configurations for each cluster. It validates the setup by listing the kubectl contexts. Subsequently, it initializes the federation using 'kubefed init' on a designated host cluster, creating a new 'federation' context. Finally, it joins the other clusters to the federation using 'kubefed join', including the host cluster itself to efficiently utilize resources. Verification is possible using 'kubectl --context=federation get clusters'.