Kubernetes Pod and Container Concepts

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Revision as of 18:24, 24 September 2021 by Ovidiu (talk | contribs) (→‎Overview)
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Overview

A pod is the fundamental, atomic compute unit created and managed by Kubernetes. A pod groups together one or more containers. Pods are deployed on worker nodes. A pod has a well-defined lifecycle with several phases, and the pod's containers can be in one of a well-defined number of states. Kubernetes is being notified of what happens with a container by container probes.

Pod

A pod is a group of one or more containers Kubernetes deploys and manages a compute unit, and the specification for how to run the containers. Kubernetes will not manage compute entities with smaller granularity, such as containers or processes.

The containers of a pod are atomically deployed and managed as a group. A useful mental model when thinking of a pod is that of a logical host, where all its containers share a context.

Pod Operation Atomicity

Shared Context

The containers in a pod share network resources and storage. From this perspective, a pod can be thought of as a logical host with all its processes (containers) sharing the network stack and the storage available to the host.

Pod Lifecycle

Pod Phases

Pods and Nodes

Pods and Containers

Container

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Container Types

Application Container

Init Container

Ephemeral Container

Container States

Container Probes

Summary of a relationship between container probe result and overall pod situation.

Container Lifecycle Hooks

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