Scale Bare Metal cluster

How to scale your Bare Metal cluster

Scaling nodes on Bare Metal clusters

When you are horizontally scaling your Bare Metal EKS Anywhere cluster, consider the number of nodes you need for your control plane and for your data plane.

See the Kubernetes Components documentation to learn the differences between the control plane and the data plane (worker nodes).

Horizontally scaling the cluster is done by increasing the number for the control plane or worker node groups under the Cluster specification.

NOTE: If etcd is running on your control plane (the default configuration) you should scale your control plane in odd numbers (3, 5, 7…).

apiVersion: anywhere.eks.amazonaws.com/v1
kind: Cluster
metadata:
  name: test-cluster
spec:
  controlPlaneConfiguration:
    count: 1     # increase this number to horizontally scale your control plane
...    
  workerNodeGroupsConfiguration:
  - count: 1     # increase this number to horizontally scale your data plane

Next, you must ensure you have enough available hardware for the scale-up operation to function. Available hardware could have been fed to the cluster as extra hardware during a prior create command, or could be fed to the cluster during the scale-up process by providing the hardware CSV file to the upgrade cluster command (explained in detail below). For scale-down operation, you can skip directly to the upgrade cluster command .

To check if you have enough available hardware for scale up, you can use the kubectl command below to check if there are hardware with the selector labels corresponding to the controlplane/worker node group and without the ownerName label.

kubectl get hardware -n eksa-system --show-labels

For example, if you want to scale a worker node group with selector label type=worker-group-1, then you must have an additional hardware object in your cluster with the label type=worker-group-1 that doesn’t have the ownerName label.

In the command shown below, eksa-worker2 matches the selector label and it doesn’t have the ownerName label. Thus, it can be used to scale up worker-group-1 by 1.

kubectl get hardware -n eksa-system --show-labels 
NAME                STATE       LABELS
eksa-controlplane               type=controlplane,v1alpha1.tinkerbell.org/ownerName=abhnvp-control-plane-template-1656427179688-9rm5f,v1alpha1.tinkerbell.org/ownerNamespace=eksa-system
eksa-worker1                    type=worker-group-1,v1alpha1.tinkerbell.org/ownerName=abhnvp-md-0-1656427179689-9fqnx,v1alpha1.tinkerbell.org/ownerNamespace=eksa-system
eksa-worker2                    type=worker-group-1

If you don’t have any available hardware that match this requirement in the cluster, you can setup a new hardware CSV . You can feed this hardware inventory file during the upgrade cluster command .

Upgrade Cluster Command for Scale Up/Down

With Hardware CSV File

eksctl anywhere upgrade cluster -f cluster.yaml --hardware-csv <hardware.csv>

Without Hardware CSV File

eksctl anywhere upgrade cluster -f cluster.yaml

Autoscaling

EKS Anywhere supports autoscaling of worker node groups using the Kubernetes Cluster Autoscaler and as a curated package .

See here for details on how to configure your cluster spec to autoscale worker node groups for autoscaling.