This page explains two different approaches to setting up a highly available Kubernetes cluster using kubeadm: With stacked control plane nodes. This approach requires less infrastructure. The etcd members and control plane nodes are co-located. With an external etcd cluster. This approach requires more infrastructure. The control plane nodes and etcd members are separated. Before proceeding, you should carefully consider which approach best meets the needs of your applications and environment.

FEATURE STATE: Kubernetes v1.28 [alpha] (enabled by default: false) Kubernetes 1.33 includes an alpha feature that lets an API Server proxy a resource requests to other peer API servers. This is useful when there are multiple API servers running different versions of Kubernetes in one cluster (for example, during a long-lived rollout to a new release of Kubernetes). This enables cluster administrators to configure highly available clusters that can be upgraded more safely, by directing resource requests (made during the upgrade) to the correct kube-apiserver.

An overview of the key components that make up a Kubernetes cluster.

FEATURE STATE: Kubernetes v1.22 [alpha] This document describes how to run Kubernetes Node components such as kubelet, CRI, OCI, and CNI without root privileges, by using a user namespace. This technique is also known as rootless mode. Note:This document describes how to run Kubernetes Node components (and hence pods) as a non-root user. If you are just looking for how to run a pod as a non-root user, see SecurityContext.

The cloud-controller-manager is a Kubernetes control plane component that embeds cloud-specific control logic. The cloud controller manager lets you link your cluster into your cloud provider's API, and separates out the components that interact with that cloud platform from components that only interact with your cluster. By decoupling the interoperability logic between Kubernetes and the underlying cloud infrastructure, the cloud-controller-manager component enables cloud providers to release features at a different pace compared to the main Kubernetes project.

Define a range of valid CPU resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.

All of the APIs in Kubernetes that let you write persistent API resource data support at-rest encryption. For example, you can enable at-rest encryption for Secrets. This at-rest encryption is additional to any system-level encryption for the etcd cluster or for the filesystem(s) on hosts where you are running the kube-apiserver. This page shows how to switch from encryption of API data at rest, so that API data are stored unencrypted.

This page covers how to customize the components that kubeadm deploys. For control plane components you can use flags in the ClusterConfiguration structure or patches per-node. For the kubelet and kube-proxy you can use KubeletConfiguration and KubeProxyConfiguration, accordingly. All of these options are possible via the kubeadm configuration API. For more details on each field in the configuration you can navigate to our API reference pages. Note:Customizing the CoreDNS deployment of kubeadm is currently not supported.

Kubernetes is designed with self-healing capabilities that help maintain the health and availability of workloads. It automatically replaces failed containers, reschedules workloads when nodes become unavailable, and ensures that the desired state of the system is maintained. Self-Healing capabilities Container-level restarts: If a container inside a Pod fails, Kubernetes restarts it based on the restartPolicy. Replica replacement: If a Pod in a Deployment or StatefulSet fails, Kubernetes creates a replacement Pod to maintain the specified number of replicas.

This guide is for application owners who want to build highly available applications, and thus need to understand what types of disruptions can happen to Pods. It is also for cluster administrators who want to perform automated cluster actions, like upgrading and autoscaling clusters. Voluntary and involuntary disruptions Pods do not disappear until someone (a person or a controller) destroys them, or there is an unavoidable hardware or system software error.