<p>I am using EKS with node group for K8S.<br />
The desired node is 1 and the maximum is 3.</p>
<p>Currently, there is only one ec2 (t3.xlarge) is running.<br />
When I deploy two pods in one namespace, each requests 8G memory and 2 CPU, the first one is deployed successfully but the second one failed with the error <code>1 Insufficient cpu, 1 Insufficient memory</code>.</p>
<p>I expect EKS should scale up one more node to allocate this new pod but it doesn't.<br />
Does anyone know why the auto-scale doesn't happen?
What am I understand wrong?</p>

<p>With Amazon EKS you need to follow those rules prior to use AutoScaler</p>
<p><a href="https://docs.aws.amazon.com/eks/latest/userguide/cluster-autoscaler.html" rel="nofollow noreferrer">https://docs.aws.amazon.com/eks/latest/userguide/cluster-autoscaler.html</a></p>
<h3>From the Official Docs above:</h3>
<p><strong>I have highlighted what might be your problem</strong></p>
<h3>Prerequisites</h3>
<ul>
<li><p>Before deploying the Cluster Autoscaler, you must meet the following prerequisites:</p>
</li>
<li><p>Have an existing Amazon EKS cluster – If you don’t have a cluster, see Creating an Amazon EKS cluster.</p>
</li>
<li><p>An existing IAM OIDC provider for your cluster. To determine whether you have one or need to create one, see Create an IAM OIDC provider for your cluster.</p>
</li>
<li><p><strong>Node groups with Auto Scaling groups tags – The Cluster Autoscaler requires the following tags on your Auto Scaling groups so that they can be auto-discovered.</strong></p>
</li>
<li><p>If you used eksctl to create your node groups, these tags are automatically applied.</p>
</li>
<li><p><strong>If you didn't use eksctl, you must manually tag your Auto Scaling groups with the following tags.</strong></p>
<div class="s-table-container">
<table class="s-table">
<thead>
<tr>
<th>Key</th>
<th>Value</th>
</tr>
</thead>
<tbody>
<tr>
<td>k8s.io/cluster-autoscaler/&lt;cluster-name&gt;</td>
<td>owned</td>
</tr>
<tr>
<td>k8s.io/cluster-autoscaler/enabled</td>
<td>TRUE</td>
</tr>
</tbody>
</table>
</div></li>
</ul>
