How to deploy Springboot or Nginx using Kubernetes

1 Preface

This is very simple, just a yaml file.

2 One-click deployment of springboot

2.1 Prepare yaml file

When the image file is ready, deploy it to kubernetes It's very easy. You only need a file in the format of yaml. This file can describe the components you need, such as deployment, service, ingressetc. The definition is as follows:

apiversion: apps/v1
kind: deployment
metadata:
 name: pkslow-springboot-deployment
spec:
 selector:
 matchlabels:
  app: springboot
 replicas: 2
 template:
 metadata:
  labels:
  app: springboot
 spec:
  containers:
  - name: springboot
   image: pkslow/springboot-mongo:0.0.6
   ports:
   - containerport: 8080

---
apiversion: v1
kind: service
metadata:
 labels:
 app: springboot
 name: pkslow-springboot-service
spec:
 ports:
 - port: 8080
  name: springboot-service
  protocol: tcp
  targetport: 8080
  nodeport: 30080
 selector:
 app: springboot
 type: nodeport

kind: Type, including deployment, service, pod, ingress, etc., very rich;

metadata: used to define some component information, such as names, labels, etc.;

labels: label function , very useful for selecting associations; but label does not provide uniqueness, you can use combinations to select;

nodeport: For services that need to be exposed to the outside, There are three ways: nodeports, loadbalancer, ingress, here nodeports is used; it should be noted that its default port range is [3000-32767], if you need other ranges, you need to modify the relevant parameters.

2.2 Deployment through kubectl command

When the yaml file is ready, it can be deployed through the following command:

$ kubectl create -f pksow-springboot.yaml 
deployment.apps/pkslow-springboot-deployment created
service/pkslow-springboot-service created

Looking at the console log shows deployment and service were created successfully. View dashboard as follows:

Access web service:

Check it through the command line:

$ kubectl get deployment
name       ready up-to-date available age
pkslow-springboot-deployment 2/2  2   2   8m2s

$ kubectl get service
name      type  cluster-ip  external-ip port(s)   age
kubernetes     clusterip 10.96.0.1  <none>  443/tcp   10m
pkslow-springboot-service nodeport 10.102.218.119 <none>  8080:30080/tcp 8m7s

$ kubectl get pod
name           ready status restarts age
pkslow-springboot-deployment-68dffc6795-874tp 1/1  running 0   8m15s
pkslow-springboot-deployment-68dffc6795-89xww 1/1  running 0   8m15s

At this point, we have successfully published springboot to kubernetes.

2.3 Try killing a pod?

kubernetesThe smallest management element is not the container, but pod.

Let’s try to delete a pod and see what happens?

$ kubectl delete pod pkslow-springboot-deployment-68dffc6795-89xww
pod "pkslow-springboot-deployment-68dffc6795-89xww" deleted

$ kubectl get pod
name           ready status restarts age
pkslow-springboot-deployment-68dffc6795-874tp 1/1  running 0   13m
pkslow-springboot-deployment-68dffc6795-gpw67 1/1  running 0   46s

It can be found that after deleting another pod, a new pod will be automatically generated for us, which can improve the high availability of the entire service.

2.4 Try killing a container?

Let's explore what will happen if we kill a container instance.

$ docker ps
$ docker rm -f 57869688a226
57869688a226

$ docker ps

After experiments, after killing a container, a container instance will be automatically regenerated for us. The pod will not change or be regenerated.

2.5 Rapid expansion of pod

User requests suddenly increase and the service cannot support it. At this time, you need to increase the number of pod. Just modify the replicas of the yaml configuration file and update it to replicas: 4. Then execute the following command:

$ kubectl apply -f pksow-springboot.yaml

View dashboard. Based on the original two pod, two more have been added.

3 One-click deployment of nginx

If you don’t have a springboot image, you can use the officialnginx Mirror, yaml file is as follows:

apiversion: apps/v1
kind: deployment
metadata:
 name: nginx-deployment
spec:
 selector:
 matchlabels:
  app: nginx
 replicas: 3
 template:
 metadata:
  labels:
  app: nginx
 spec:
  containers:
  - name: nginx
   image: nginx:1.19.0
   ports:
   - containerport: 80

---
apiversion: v1
kind: service
metadata:
 labels:
 app: nginx
 name: nginx-service
spec:
 ports:
 - port: 80
  name: nginx-service1
  protocol: tcp
  targetport: 80
  nodeport: 30000
 - port: 81
  name: nginx-service2
  protocol: tcp
  targetport: 80
  nodeport: 30001
 selector:
 app: nginx
 type: nodeport

Execute deployment command:

$ kubectl apply -f nginx-deployment-scale.yaml 
deployment.apps/nginx-deployment created
service/nginx-service created

View dashboard as follows:

Access service: or . Because we set up two.

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