We will deploy an sample nginx application as a
ReplicaSet of 1
cat <<EoF> ~/environment/cluster-autoscaler/nginx.yaml apiVersion: apps/v1 kind: Deployment metadata: name: nginx-to-scaleout spec: replicas: 1 selector: matchLabels: app: nginx template: metadata: labels: service: nginx app: nginx spec: containers: - image: nginx name: nginx-to-scaleout resources: limits: cpu: 500m memory: 512Mi requests: cpu: 500m memory: 512Mi EoF kubectl apply -f ~/environment/cluster-autoscaler/nginx.yaml kubectl get deployment/nginx-to-scaleout
OK, let’s scale out the replicaset to 10
kubectl scale --replicas=10 deployment/nginx-to-scaleout
Some pods will be in the
Pending state, which triggers the cluster-autoscaler to scale out the EC2 fleet.
kubectl get pods -o wide --watch
View the cluster-autoscaler logs
kubectl logs -f deployment/cluster-autoscaler -n kube-system
You will notice Cluster Autoscaler events similar to below
Check the AWS Management Console to confirm that the Auto Scaling groups are scaling up to meet demand. This may take a few minutes. You can also follow along with the pod deployment from the command line. You should see the pods transition from pending to running as nodes are scaled up.