Federated NGINX Service

This lab will walk you through creating a federated NGINX service using replica sets and services. For more details on how federated replica sets work review the Federated ReplicaSet Requirements & Design Document

Prerequisites

Store the GCP Project Name

export GCP_PROJECT=$(gcloud config list --format='value(core.project)')

Federated NGINX ReplicaSet

Federated replica sets leverage the same configuration as a non-federated Kubernetes clusters. By default pods created by a replica set are distributed evenly across all configured clusters.

kubectl --context=federation-cluster get clusters

NAME               STATUS    VERSION   AGE
gce-asia-east1     Ready     1h
gce-europe-west1   Ready     1h
gce-us-central1    Ready     1h
gce-us-east1       Ready     1h

The following command will create an nginx replica set and create 4 nginx pods.

kubectl --context=federation-cluster create -f rs/nginx.yaml

Verify

kubectl --context=federation-cluster get rs

NAME      DESIRED   CURRENT   AGE
nginx     4         0         13m

List Pods

List the cluster level nginx pods for the following cluster contexts:

gke_${GCP_PROJECT}_asia-east1-b_gce-asia-east1
gke_${GCP_PROJECT}_europe-west1-b_gce-europe-west1
gke_${GCP_PROJECT}_us-east1-b_gce-us-east1
gke_${GCP_PROJECT}_us-central1-b_gce-us-central1

Example

kubectl --context="gke_${GCP_PROJECT}_us-central1-b_gce-us-central1" get pods

NAME          READY     STATUS    RESTARTS   AGE
nginx-z5wkd   1/1       Running   0          3m

Federated NGINX ReplicaSet with Preferences

An annotation can be used to control which clusters pods are scheduled to.

apiVersion: extensions/v1beta1
kind: ReplicaSet
metadata:
  name: nginx-us
  annotations:
    federation.kubernetes.io/replica-set-preferences: |
        {
            "rebalance": true,
            "clusters": {
                "gce-us-east1": {
                    "minReplicas": 2,
                    "maxReplicas": 4,
                    "weight": 1
                },
                "gce-us-central1": {
                    "minReplicas": 2,
                    "maxReplicas": 4,
                    "weight": 1
                }
            }
        }

The follow command will create pods only in the gce-us-east1 and gce-us-central1 clusters

kubectl --context=federation-cluster create -f rs/nginx-us.yaml

Verify

List pods in the gce-us-central1 cluster:

kubectl --context="gke_${GCP_PROJECT}_us-central1-b_gce-us-central1" get pods

NAME              READY     STATUS    RESTARTS   AGE
nginx-us-bh867    1/1       Running   0          27s
nginx-us-p932u    1/1       Running   0          27s

List pods in the gce-us-east1 cluster:

kubectl --context="gke_${GCP_PROJECT}_us-east1-b_gce-us-east1" get pods

NAME              READY     STATUS    RESTARTS   AGE
nginx-us-4rh2t    1/1       Running   0          44s
nginx-us-ejtvm    1/1       Running   0          44s

Notice there are no nginx-us pods running in the gce-europe-west1 cluster:

kubectl --context="gke_${GCP_PROJECT}_europe-west1-b_gce-europe-west1" get pods