SRE文档

深浅模式

1.Deployment场景实践 ​

场景说明：运⾏⼀个demoapp的应⽤，部署3个副本，然后通过service来实现负载均衡；

  • 创建 Deployment资源，部署三个副本
  • 创建 Service资源，通过标签选择器选择对应的Pod，以实现负载均衡；
  • ⽤ curl命令，或Chrome浏览器验证集群⾼可⽤；

image-20240430151005538

1.1 创建 ​

  • 创建yaml文件
yaml
[root@kube-master yaml]# cat test.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
      - name: demo-container
        image: registry.cn-zhangjiakou.aliyuncs.com/hsuing/demoapp:v1
        ports:
        - name: http-server
          containerPort: 80
[root@kube-master yaml]# cat test.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
      - name: demo-container
        image: registry.cn-zhangjiakou.aliyuncs.com/hsuing/demoapp:v1
        ports:
        - name: http-server
          containerPort: 80
  • 查看
shell
[root@kube-master yaml]# kubectl get pod
NAME                               READY   STATUS    RESTARTS         AGE
demo-deployment-6b9fc7dc7f-fnsb2   1/1     Running   0                8s
demo-deployment-6b9fc7dc7f-r4j2l   1/1     Running   0                8s
demo-deployment-6b9fc7dc7f-sqw7c   1/1     Running   0                8s
[root@kube-master yaml]# kubectl get pod
NAME                               READY   STATUS    RESTARTS         AGE
demo-deployment-6b9fc7dc7f-fnsb2   1/1     Running   0                8s
demo-deployment-6b9fc7dc7f-r4j2l   1/1     Running   0                8s
demo-deployment-6b9fc7dc7f-sqw7c   1/1     Running   0                8s

1.2 检查dp状态 ​

检查集群的 Deployment ​

shell
[root@kube-master yaml]# kubectl get deployments.apps
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
demo-deployment   3/3     3            3           79s
[root@kube-master yaml]# kubectl get deployments.apps
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
demo-deployment   3/3     3            3           79s

每列参数含义

NAME 列出了集群中 Deployment 的名称

READY 显示应⽤程序的可⽤的“副本”数。显示的模式是“就绪个数/期望个数”

UP-TO-DATE 显示为了达到期望状态已经更新的副本数

AVAILABLE 显示应⽤可供⽤户使⽤的副本数

AGE 显示应⽤程序运⾏的时间

💡 说明

期望副本数是根据 .spec.replicas 字段设置 3

检查集群的 ReplicaSet ​

shell
[root@kube-master yaml]# kubectl get rs
NAME                         DESIRED   CURRENT   READY   AGE
demo-deployment-6b9fc7dc7f   3         3         3       6m35s
[root@kube-master yaml]# kubectl get rs
NAME                         DESIRED   CURRENT   READY   AGE
demo-deployment-6b9fc7dc7f   3         3         3       6m35s

NAME 列出名字空间中 ReplicaSet 的名称

DESIRED 显示应⽤的期望副本个数，即在创建 Deployment 时所定义的值。 此为期望状态

CURRENT 显示当前运⾏状态中的副本个数

READY 显示应⽤中有多少副本可以为⽤户提供服务；

AGE 显示应⽤已经运⾏的时间⻓度

❌ 注意

ReplicaSet 的名称被格式化为[Deployment名称]-[随机字符串]

  • 检查pod 是否为3个
shell
[root@kube-master yaml]# kubectl get pod
NAME                               READY   STATUS    RESTARTS        AGE
demo-deployment-6b9fc7dc7f-fnsb2   1/1     Running   0               11m
demo-deployment-6b9fc7dc7f-r4j2l   1/1     Running   0               11m
demo-deployment-6b9fc7dc7f-sqw7c   1/1     Running   0               11m
[root@kube-master yaml]# kubectl get pod
NAME                               READY   STATUS    RESTARTS        AGE
demo-deployment-6b9fc7dc7f-fnsb2   1/1     Running   0               11m
demo-deployment-6b9fc7dc7f-r4j2l   1/1     Running   0               11m
demo-deployment-6b9fc7dc7f-sqw7c   1/1     Running   0               11m

1.3 创建Service ​

  • 创建yaml文件
yaml
[root@kube-master yaml]# cat test_svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: demo-service
spec:
  selector:				#类似upstream
    app: demo
  ports:
  - name: http	
    port: 8080			# service对外提供的端⼝
    targetPort: 80		# Pod的端⼝
[root@kube-master yaml]# cat test_svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: demo-service
spec:
  selector:				#类似upstream
    app: demo
  ports:
  - name: http	
    port: 8080			# service对外提供的端⼝
    targetPort: 80		# Pod的端⼝
  • 生成
shell
[root@kube-master yaml]# kubectl apply  -f test_svc.yaml
service/demo-service created
[root@kube-master yaml]# kubectl apply  -f test_svc.yaml
service/demo-service created
  • 查看svc地址
shell
[root@kube-master yaml]# kubectl get svc -owide
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE     SELECTOR
demo-service   ClusterIP   192.168.15.149   <none>        8080/TCP         2m11s   app=demo
[root@kube-master yaml]# kubectl get svc -owide
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE     SELECTOR
demo-service   ClusterIP   192.168.15.149   <none>        8080/TCP         2m11s   app=demo
  • 验证集群的可用性
shell
[root@kube-master yaml]# curl 192.168.15.149:8080
hsuing demoapp v1.1 !! ClientIP: 172.25.244.192, PodName: demo-deployment-bf8f88dbc-b5dmc, PodIP: 172.30.0.142!
[root@kube-master yaml]# curl 192.168.15.149:8080
hsuing demoapp v1.1 !! ClientIP: 172.25.244.192, PodName: demo-deployment-bf8f88dbc-b5dmc, PodIP: 172.30.0.142!

1.4 ⽔平伸缩 ​

水平扩展/收缩的功能比较简单，修改replicas对应的副本数即可。比如将Pod 的副本调整到5个，那么Deployment所管理的ReplicaSet则会自动创建一个新的Pod出来，这样就实现水平扩展

shell
kubectl scale deployment demo-deployment --replicas=4

#或者通过edit方式修改
 kubectl edit deployments.apps demo-deployment
 
#或者 通过patch
kubectl patch deployments.apps demo-deployment -p '{"spec":{"replicas":4}}'
deployment.apps/demo-deployment patched
kubectl scale deployment demo-deployment --replicas=4

#或者通过edit方式修改
 kubectl edit deployments.apps demo-deployment
 
#或者 通过patch
kubectl patch deployments.apps demo-deployment -p '{"spec":{"replicas":4}}'
deployment.apps/demo-deployment patched

💡 说明

在deployment 管理下，删除其中一个pod之后，dp回自动补齐副本数