kubernetes基础使用

官方文档：https://v1-13.docs.kubernetes.io/zh/docs/tutorials/kubernetes-basics/
pods生命周期:https://v1-13.docs.kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/
配置: https://v1-13.docs.kubernetes.io/docs/concepts/configuration/
labels: https://v1-13.docs.kubernetes.io/docs/concepts/overview/working-with-objects/labels/
Deployments: https://v1-13.docs.kubernetes.io/docs/concepts/workloads/controllers/deployment/
Services: https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/service/
Scaling: https://v1-13.docs.kubernetes.io/docs/tutorials/kubernetes-basics/scale/scale-intro/
autoscale: https://v1-13.docs.kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/

#查看k8s版本
kubectl version

#查看所有的节点
kubectl get nodes

#部署应用
kubectl run  kubernetes-bootcamp --image=jocatalin/kubernetes-bootcamp:v1 --port=8080

#查看部署应用列表 
kubectl get deployments 

#查看所有pod
kubectl get pods

#获取执行中的pod并设置成环境变量POD_NAME
export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
echo Name of the Pod: $POD_NAME

#访问pod
curl http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/proxy/

kubectl 故障排查

kubectl get pods #查看resources列表
kubectl describe pods  #查看具体的resources情况
kubectl logs $POD_NAME  #查看pod里的容器日志
kubectl exec #在pod里的容器里执行命令
kubectl exec $POD_NAME env #查看pod环境变量
kubectl exec -ti $POD_NAME bash #进入pod终端

Service & labels
Service type

labels
service通过labels把一组pods管理起来。
比如通过labels指定开发、测试、生产环境
比如打版本tag
使用标签分类

#获取service
kubectl get services 

#指定service type
kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080 

#查看指定services信息
kubectl describe services/kubernetes-bootcamp

#设置NODE_PORT端口为环境变量
export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
echo NODE_PORT=$NODE_PORT

#查看部署情况
kubectl describe deployment 

#-l根据label查询pods
kubectl get pods -l run=kubernetes-bootcamp

#-l根据label查询services 
kubectl get services -l run=kubernetes-bootcamp

export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
echo Name of the Pod: $POD_NAME

#设置label,label是key/value对
kubectl label pod $POD_NAME app=v1

#根据label查询pods
kubectl get pods -l app=v1

#删除service
kubectl delete service -l run=kubernetes-bootcamp

#pod里执行命令
kubectl exec -ti $POD_NAME curl localhost:808

扩缩容

kubectl get deployments

#扩容成4个
kubectl scale deployments/kubernetes-bootcamp --replicas=4

#查看pod是否变成4个
kubectl get pods -o wide

#查看deployments详情
kubectl describe deployments/kubernetes-bootcamp

#设置环境变量
export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
echo NODE_PORT=$NODE_PORT

#缩容
kubectl scale deployments/kubernetes-bootcamp --replicas=2

滚动升级

#查看deployments
kubectl get deployments
kubectl get pods
kubectl describe pods
#滚动升级
kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2

#查看升级是否成功
kubectl describe services/kubernetes-bootcamp

#查看升级状态
kubectl rollout status deployments/kubernetes-bootcamp

#升级一个不存在的版本，让升级失败。
kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-samples/kubernetes-bootcamp:v10

#查看pods是否失败
kubectl  get pods

#查看失败日志
kubectl logs  $POD_NAME

#回退版本，然后用上面的命令查看是否回退成功
kubectl rollout undo deployments/kubernetes-bootcamp

根据上面的内容部署官网的例子:https://kubernetes.io/docs/tutorials/stateless-application/guestbook/
image 从docker hub 上找，先pull下来

#在有问题的node上执行以下命令 查看问题
journalctl -f -u kubelet