How to deploy applications on kubernetes cluster

  brief introduction ：  In this article, we will introduce how to Kubernetes Create a remote image on the cluster , And use the image deployment service through the command line .

Image download 、 Domain name resolution 、 Time synchronization please click   Alibaba open source mirror site

Preface

In this paper , We will learn how to deploy a simple application in a cluster .

We can set k8s Deployment configuration for , To control k8s How to create and update your application instances , Once the deployment settings are created , The main node of the cluster will schedule application instances according to your configuration , Deployed on each node of the cluster .

After deployment ,k8s It will continue to monitor the running status of the application instance on each node , Once there is downtime 、 Deleted, etc ,k8s New application instances will be created on other nodes of the cluster , To meet your deployment configuration settings . This is also different from the previous deployment methods , utilize k8s Deploy the application , It can help you improve the high availability of the system .

Prepare the mirror

First, we need to prepare an application image , because k8s The application of the upper deployment needs to be containerized .

You can directly use my built registry.cn-hangzhou.aliyuncs.com/larswang/hello-node:1.0 Mirror image , Skip this paragraph , Look directly at   establish Deployment .

You can also refer to the following methods Build your own mirror image .

Let's use docker Create a simple NodeJS Service image .（ If not already installed docker Your friends can use Alibaba cloud image source Download and install ）.

Code preparation

You can use it directly hello-node Content of code warehouse

server.js

var http = require('http');

var handleRequest = function(request, response) {
  console.log('Received request for URL: ' + request.url);
  response.writeHead(200);
  response.end('Hello World!');
};
var www = http.createServer(handleRequest);
www.listen(8080);

Dockerfile

FROM node:6.14.2
EXPOSE 8080
COPY server.js .
CMD [ "node", "server.js" ]

Build a mirror image

I use Alibaba cloud's image warehouse ： Access now

Create a mirror repository

Associated source code

Build immediately

Building a successful

Local pull

docker pull registry.cn-hangzhou.aliyuncs.com/larswang/hello-node:1.0
docker run --name node-test -p 8080:8080 -d registry.cn-hangzhou.aliyuncs.com/larswang/hello-node:1.0

Local access ：http://localhost:8080/, You can see Hello World! Output . Explain the image construction OK.

Deployment

Deployment It is used to deploy stateless applications , That is, describe the stateless application cluster state , Such as setting deployment 5 Copies , When one of the replicas goes down , Will automatically expand to 5 Copies .

kubectl create deployment hello-node --image=registry.cn-hangzhou.aliyuncs.com/larswang/hello-node:1.0

see deployment

kubectl get deployments

see pod

kubectl get pods

Service

Default Pod Only through Kubernetes Inside the cluster IP Address access , In order to carry on Kubernetes External access to virtual networks , Need to put Pod Exposure to Kubernetes Service.

kubectl expose deployment hello-node --type=LoadBalancer --port=8080

adopt LoadBalancer Type of way will cluster services 8080 Ports exposed .
see Services

kubectl get services

visit Service

minikube service hello-node

The browser will automatically open http://127.0.0.1:51284, Show Hello World!

clear

You can clean up the resources created in the cluster with the following commands .

kubectl delete service hello-node
kubectl delete deployment hello-node

summary

In this article, we introduced how to create a remote image , And use the image deployment service through the command line .

In this paper, from ： How to be in Kubernetes Deploy applications on the cluster - Alicloud developer community