Horizontal pod autoscaling in Kubernetes

The HPA controller is part of the controller manager and you'll need to pass the flags to it, see also the docs. It is not something you'd do via kubectl. It's part of the control plane (master) so depends on how you set up Kubernetes and/or which offering you're using. For example, in GKE the control plane is not accessible, in Minikube you'd ssh into the node, etc.

As per all the discussion over here is my experience and it's working for me, may be it can help someone.

ssh to master node and edit /etc/kubernetes/manifests/kube-controller-manager.manifest like below

command:
- /hyperkube
- controller-manager
- --kubeconfig=/etc/kubernetes/kube-controller-manager-kubeconfig.yaml
- --leader-elect=true
- --service-account-private-key-file=/etc/kubernetes/ssl/service-account-key.pem
- --root-ca-file=/etc/kubernetes/ssl/ca.pem
- --cluster-signing-cert-file=/etc/kubernetes/ssl/ca.pem
- --cluster-signing-key-file=/etc/kubernetes/ssl/ca-key.pem
- --enable-hostpath-provisioner=false
- --node-monitor-grace-period=40s
- --node-monitor-period=5s
- --pod-eviction-timeout=5m0s
- --profiling=false
- --terminated-pod-gc-threshold=12500

- --horizontal-pod-autoscaler-downscale-delay=2m0s
- --horizontal-pod-autoscaler-upscale-delay=2m0s

- --v=2
- --use-service-account-credentials=true
- --feature-gates=Initializers=False,PersistentLocalVolumes=False,VolumeScheduling=False,MountPropagation=False

The quoted part is the parameters I have added. without restarting the kubelet service it's updated.

If you don't find this value updated you can restart systemctl restart kubelet.

Note : I have created HA-cluster using kubespray

Hope this can be savior for someone.

Thank you!