Metrics Server

https://github.com/kubernetes-sigs/metrics-server

Requirements

Metrics Server has specific requirements for cluster and network configuration. These requirements aren't the default for all cluster
distributions. Please ensure that your cluster distribution supports these requirements before using Metrics Server:

• The kube-apiserver must [enable an aggregation layer].
• Nodes must have Webhook [authentication and authorization] enabled.
• Kubelet certificate needs to be signed by cluster Certificate Authority (or disable certificate validation by passing --kubelet-insecure-tls to Metrics Server)
• Container runtime must implement a [container metrics RPCs] (or have [cAdvisor] support)
• Network should support following communication:
  • Control plane to Metrics Server. Control plane node needs to reach Metrics Server's pod IP and port 10250 (or node IP and custom port if hostNetwork is enabled). Read more about control plane to node communication.
  • Metrics Server to Kubelet on all nodes. Metrics server needs to reach node address and Kubelet port. Addresses and ports are configured in Kubelet and published as part of Node object. Addresses in .status.addresses and port in .status.daemonEndpoints.kubeletEndpoint.port field (default 10250). Metrics Server will pick first node address based on the list provided by kubelet-preferred-address-types command line flag (default InternalIP,ExternalIP,Hostname in manifests).