Shulou(Shulou.com)05/31 Report--

This article mainly introduces the kubernetes Pod initialization container Init Container example analysis, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

One: preface

In many application scenarios, the application needs to be initialized as follows before launching

1. Wait for other associated components to run correctly (such as a database)

two。 Generate configuration files based on environment variables or configuration templates

3. Get the required local configuration from a remote database, or register yourself with a central database

4. Download related dependency packages, or do some configuration operations on the system

Init container is essentially the same as an application container, but they are tasks that end only once, and must be successfully completed before the system can proceed to the next container.

Two: examples

Nginx-init-containers.yaml

ApiVersion: v1

Kind: Pod

Metadata:

Name: nginx

Spec:

InitContainers:

-name: install

Image: busybox

Command:

-wget

-"- O"

-"/ work-dir/index.html"

-http://kubernetes.io

VolumeMounts:

-name: workdir

MountPath: "/ work-dir"

Containers:

-name: nginx

Image: nginx

Ports:

-containerPort: 80

VolumeMounts:

-name: workdir

MountPath: / usr/share/nginx/html

Volumes:

-name: workdir

EmptyDir: {}

Kubectl create-f nginx-init-containers.yaml

Kubectl describe pod nginx

Three: explanation

The difference between init container and application container

1. The mode of operation is different. They must be executed before the application container. When multiple init container are set, they will be run one by one in order. When all the init container runs successfully, the kubernetes will initialize all kinds of Pod information.

two。 Resource restrictions, volume usage and security policies can also be set in the definition of init container, but slightly different from the application container

3.init container cannot set readinessProbe probes because they must be run successfully before continuing to run the normal containers defined in Pod

4. When Pod restarts, init container will rerun

Thank you for reading this article carefully. I hope the article "sample Analysis of Init Container of Pod initialization Container in kubernetes" shared by the editor will be helpful to you. At the same time, I also hope that you will support and follow the industry information channel. More related knowledge is waiting for you to learn!

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