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How Cluster Autoscaler helps Scaling for EKS cluster:

Kubernetes is a popular container orchestration technology with advanced capabilities for deploying, scaling, and maintaining containerized applications. The capacity of K8s to independently scale resources up or down in response to application demand is one of their main advantages. This scalability is only possible for the resources on a single node, which can be a problem for workloads that are very dynamic.

Cluster autoscaling is a function that automatically scales an entire cluster based on resource use. This blog will talk about the Cluster Autoscaler for K8s, covering its definition, operation, and configuration.

What is Cluster Autoscaler for K8s?

A K8s component called Cluster Autoscaler automatically changes a cluster’s size in response to resource demand. It adds or removes nodes from the cluster as necessary and keeps track of CPU, memory, and network bandwidth use. This ensures that resources are not wasted during times of low demand and that apps function without interruption even during times of high demand.

How does Cluster Autoscaler work?

A K8S cluster’s nodes are thoroughly inspected for resource use by the cluster’s autoscaler. It will intervene to scale the cluster appropriately if it notices that resources are being misused or overused.

When a node is added to a K8s cluster, it is automatically labeled with a node selector that identifies the node as a potential candidate for autoscaling. The cluster autoscaler then monitors the resource utilization of these nodes and determines whether or not to add or remove nodes based on the desired resource utilization level.

When a node needs to be added to the cluster, the cluster autoscaler will create a new node and add it to the cluster. This new node will be configured with the necessary labels and taints to ensure that it is appropriately utilized by the cluster.

When a node needs to be removed from the cluster, the cluster autoscaler will first drain the node of all its workloads, ensuring that they are rescheduled to other nodes in the cluster. Once the node is empty, it will be removed from the cluster.

How to configure Cluster Autoscaler for K8s?

To configure cluster autoscaler for K8s, you will need to follow these steps:

Step 1: Install the Cluster Autoscaler
The first step is to install the cluster autoscaler component into your K8s cluster. This can be done by running the appropriate Kubectl command or by using a K8s deployment tool such as Helm.
Check out the article on installing Cluster Autoscaler for EKS cluster.

Step 2: Configure the Cluster Autoscaler
Next, you will need to configure the cluster autoscaler to work with your K8s cluster. This involves specifying the cluster’s minimum and maximum number of nodes and the desired resource utilization level.

Step 3: Test the Cluster Autoscaler
Once the cluster autoscaler is installed and configured, you should test it to ensure that it is working correctly. You can do this by simulating a high load on your cluster and observing how the autoscaler responds.

Step 4: Monitor the Cluster Autoscaler
Finally, you should regularly monitor the cluster autoscaler to ensure that it is working as expected. This includes monitoring resource utilization levels, node counts, and any events or errors that may occur.


The cluster autoscaler is a powerful tool for K8s that automatically scale an entire cluster based on resource utilization. By monitoring resource utilization levels and adding or removing nodes from the cluster as needed, the cluster autoscaler can help ensure that applications run smoothly even during periods of high demand.