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This article will explain in detail how to carry out Pod analysis, the quality of the article content is high, so Xiaobian shared with you as a reference, I hope you have a certain understanding of relevant knowledge after reading this article.

The concept of Pod

Although Kubernetes is a container orchestration system, it does not directly manage containers, but objects called pods.

Pod is an advanced abstract image of container. The word pod means pod in English, which vividly reveals its relationship to container. Just like a pod can contain one or more beans, a Pod can also contain one or more containers.

In Kubernetes, pods are the most basic objects. No matter how many containers are contained in a Pod, the creation and destruction of a pod corresponds to the creation and destruction of all the containers it contains.

Pod's Advantages

When deploying containerized applications, sometimes we want multiple closely related containers to be deployed on the same node, so that they can easily share local storage, communicate with each other, and even create and destroy them together.

For example, we have a container for running a Web server, and another container for managing data from the Web server. Considering that two containers need to share storage, it is more appropriate to encapsulate these two containers into the same Pod, as shown in the following figure:

In addition to sharing the same lifecycle, containers in a Pod have different network and storage environments than managing multiple containers directly.

Kubernetes assigns a unique IP address to the Pod. The Pod provides a relatively isolated network environment for the container. The containers in the Pod use this IP address when communicating with the outside world, while the containers in the Pod can communicate directly using localhost. In this case, you only need to specify different ports for the containers communicating with each other.

If a storage volume is specified when creating a Pod, Kubernetes mounts the storage volume to each container for use by container shares.

The concept of Pod comes from Kubernetes 'accurate grasp of the actual application scenario. When you need to deploy containers separately, you only need to specify one container in the Pod. When you need to deploy multiple containers together, you only need to specify multiple containers in the Pod.

Limitations of Pod

Although pods can encapsulate containers, whereby we can do some bulk management of containers, it is rare to actually create pods directly. That's because a Pod is essentially the same as a container, it's unreliable, a Pod may terminate because the container process is abnormal, or it may not continue to run because the resources required by the container are not met, in short, a Pod will not heal itself.

Kubernetes treats a Pod as an unreliable resource that can only run containers mechanically, and Kubernetes does not re-run a Pod after it has been terminated abnormally. In order to meet the requirements of managing Pods in various scenarios, Kubernetes provides a variety of controller resources on top of Pods, such as Deployment, StatefulSet and DaemonSet, which can help us better manage Pods and ensure that Pods always operate according to our expected behavior.

Pod is just a resource in Kubernetes system, it is not a process, it is a container-based abstraction, it prepares the runtime environment for one or more containers, runs a Pod, and finally hands over the containers one by one to the container runtime to run.

Although we don't generally create pods directly in Kubernetes systems, it is the most basic resource, and most of Kubernetes features revolve around how to run and manage pods better, so you must have a certain understanding of pods before you can start learning later.

About how to carry out Pod analysis to share here, I hope the above content can be of some help to everyone, you can learn more knowledge. If you think the article is good, you can share it so that more people can see it.

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