The Kubernetes API server stores objects, relying on an etcd-compatible backing store (often, the backing storage is etcd itself). Each object is serialized using a particular version of that API type; for example, the v1 representation of a ConfigMap. Kubernetes uses the term storage version to describe how an object is stored in your cluster. The Kubernetes API also relies on automatic conversion; for example, if you have a HorizontalPodAutoscaler, then you can interact with that HorizontalPodAutoscaler using any mix of the v1 and v2 versions of the HorizontalPodAutoscaler API.

FEATURE STATE: Kubernetes v1.11 [beta] Cloud infrastructure technologies let you run Kubernetes on public, private, and hybrid clouds. Kubernetes believes in automated, API-driven infrastructure without tight coupling between components. 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.

This page provides an overview of init containers: specialized containers that run before app containers in a Pod. Init containers can contain utilities or setup scripts not present in an app image. You can specify init containers in the Pod specification alongside the containers array (which describes app containers). In Kubernetes, a sidecar container is a container that starts before the main application container and continues to run. This document is about init containers: containers that run to completion during Pod initialization.

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.

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.

Resources that Kubernetes provides for configuring Pods.

In Kubernetes, Services are an abstract way to expose an application running on a set of Pods. Services can have a cluster-scoped virtual IP address (using a Service of type: ClusterIP). Clients can connect using that virtual IP address, and Kubernetes then load-balances traffic to that Service across the different backing Pods. How Service ClusterIPs are allocated? When Kubernetes needs to assign a virtual IP address for a Service, that assignment happens one of two ways:

Production-Grade Container Orchestration

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

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