kubernetes 作为一个云上的操作系统，要想充分利用，就要了解 kubernetes 提供的功能。告诉系统要搞啥，k8s 帮你搞定这一切，归根结底，不开发 k8s 就是一个 k8s 的用户，知道 k8s 能具体做啥，写好 YAML 就可以。

如何在 k8s 上部署服务

create Deployment

One of the most common Kubernetes object is the deployment object. The deployment object defines the container spec required, along with the name and labels used by other parts of Kubernetes to discover and connect to the application.

准备 deployment.yaml

The definition defines how to launch an application called webapp1 using the Docker Image katacoda/docker-http-server that runs on Port 80.

apiVersion: apps/v1
kind: Deployment # object type
metadata:
  name: webapp1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: webapp1
  template:
    metadata:
      labels:
        app: webapp1
    spec:
      containers:
      - name: webapp1
        image: katacoda/docker-http-server:latest
        ports:
        - containerPort: 80

部署到 k8s 中

kubectl create -f `deployment.yaml`

查看所有 deployment

kubectl get deployment

查看某一个 deployment

kubectl describe deployment `webapp1`

create Service

kubernetes has powerful networking capabilities that control how applications communicate. These networking configurations can also be controlled via YAML.

准备 service.yaml

The Service selects all applications with the label webapp1. As multiple replicas, or instances, are deployed, they will be automatically load balanced based on this common label. The Service makes the application available via a NodePort.

apiVersion: v1
kind: Service
metadata:
  name: webapp1-svc
  labels:
    app: webapp1
spec:
  type: NodePort
  ports:
  - port: 80
    nodePort: 30080
  selector:
    app: webapp1

部署到 k8s 中

kubectl create -f `service.yaml`

查看所有 service

kubectl get svc

查看某一个 deployment

kubectl describe svc `webapp1-svc`

scale Deployment

配置 replicas

apiVersion: apps/v1
kind: Deployment # object type
metadata:
  name: webapp1
spec:
  replicas: 4 # 
  selector:
    matchLabels:
      app: webapp1
  template:
    metadata:
      labels:
        app: webapp1
    spec:
      containers:
      - name: webapp1
        image: katacoda/docker-http-server:latest
        ports:
        - containerPort: 80

References

  1. https://www.katacoda.com/courses/kubernetes/kubectl-run-containers
  2. apiversion
  3. what is k8s deployment?