FEATURE STATE: Kubernetes v1.25 [stable] This page provides an overview of ephemeral containers: a special type of container that runs temporarily in an existing Pod to accomplish user-initiated actions such as troubleshooting. You use ephemeral containers to inspect services rather than to build applications. Understanding ephemeral containers Pods are the fundamental building block of Kubernetes applications. Since Pods are intended to be disposable and replaceable, you cannot add a container to a Pod once it has been created.

This page explains how to set a Pod's hostname, potential side effects after configuration, and the underlying mechanics. Default Pod hostname When a Pod is created, its hostname (as observed from within the Pod) is derived from the Pod's metadata.name value. Both the hostname and its corresponding fully qualified domain name (FQDN) are set to the metadata.name value (from the Pod's perspective) apiVersion: v1 kind: Pod metadata: name: busybox-1 spec: containers: - image: busybox:1.

Device plugins let you configure your cluster with support for devices or resources that require vendor-specific setup, such as GPUs, NICs, FPGAs, or non-volatile main memory.

When using client certificate authentication, you can generate certificates manually through easyrsa, openssl or cfssl. easyrsa easyrsa can manually generate certificates for your cluster. Download, unpack, and initialize the patched version of easyrsa3. curl -LO https://dl.k8s.io/easy-rsa/easy-rsa.tar.gz tar xzf easy-rsa.tar.gz cd easy-rsa-master/easyrsa3 ./easyrsa init-pki Generate a new certificate authority (CA). --batch sets automatic mode; --req-cn specifies the Common Name (CN) for the CA's new root certificate. ./easyrsa --batch "--req-cn=${MASTER_IP}@`date +%s`" build-ca nopass Generate server certificate and key.

Production-Grade Container Orchestration

This page explains the two options for configuring the topology of your highly available (HA) Kubernetes clusters. You can set up an HA cluster: With stacked control plane nodes, where etcd nodes are colocated with control plane nodes With external etcd nodes, where etcd runs on separate nodes from the control plane You should carefully consider the advantages and disadvantages of each topology before setting up an HA cluster.

FEATURE STATE: Kubernetes v1.29 [stable] Controlling the behavior of the Kubernetes API server in an overload situation is a key task for cluster administrators. The kube-apiserver has some controls available (i.e. the --max-requests-inflight and --max-mutating-requests-inflight command-line flags) to limit the amount of outstanding work that will be accepted, preventing a flood of inbound requests from overloading and potentially crashing the API server, but these flags are not enough to ensure that the most important requests get through in a period of high traffic.

Define a default memory resource limit for a namespace, so that every new Pod in that namespace has a memory resource limit configured.

In Kubernetes, some objects are owners of other objects. For example, a ReplicaSet is the owner of a set of Pods. These owned objects are dependents of their owner. Ownership is different from the labels and selectors mechanism that some resources also use. For example, consider a Service that creates EndpointSlice objects. The Service uses labels to allow the control plane to determine which EndpointSlice objects are used for that Service.

Production-Grade Container Orchestration