k8s工作负载-RS&&DP&&DS

RS:    ReplicaSet 的目的是维护一组在任何时候都处于运行状态的 Pod 副本的稳定集合。 因此，它通常用来保证给定数量的、完全相同的 Pod 的可用性。它也是deployment资源的基础资源，来整副本的稳定性。

RS资源实例
[root@k8smaster01 ~]# cat nginx-rs.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx-rs
spec:
  # pod副本数量
  replicas: 3
  # 标签选择器: 决定那些标签会被rs资源进行管理
  selector:
    matchLabels:
      app: nginx
      release: stable
  # 定义pod资源的模板
  template:
    metadata:
      labels:
        app: nginx
        release: stable
    spec:
      containers:
      - name: nginx-pod
        image: nginx


扩容&&缩容
# 方式一
[root@k8smaster01 ~]# kubectl edit rs nginx-rs
# 方式二
[root@k8smaster01 ~]# vim nginx-rs.yaml
[root@k8smaster01 ~]# kubectl apply -f nginx-rs.yaml








DP: Deployment 用于管理运行一个应用负载的一组 Pod，通常适用于不保持状态的负载。
增加：一个 Deployment 为 Pod 和 ReplicaSet 提供声明式的更新能力。

DP资源实例
[root@k8smaster01 ~]# cat nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80


扩容&&缩容
[root@k8smaster01 ~]# kubectl scale --replicas=10 deployment nginx-deployment
deployment.apps/nginx-deployment scaled
[root@k8smaster01 ~]# kubectl get deployments.apps
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   10/10   10           10          50m
[root@k8smaster01 ~]# kubectl scale --replicas=3 deployment nginx-deployment
deployment.apps/nginx-deployment scaled
[root@k8smaster01 ~]# kubectl get deployments.apps
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   3/3     3            3           50m



更新&&回滚
    - 更新策略
[root@k8smaster01 ~]# kubectl explain deployment.spec.strategy.type
     Type of deployment. Can be "Recreate" or "RollingUpdate". Default is RollingUpdate.
    Recreate/重建更新：
        - 在Pod资源被删除时，使用新的模板定义被补充缺失的Pod数量，完成更新
        - 触发条件：现有Pod被删除
        
    RollingUpdate/滚动更新：
        - 在Pod资源被删除时，使用新的模板定义被足缺失的Pod数量，完成更新
        - 触发条件：podTemplate的hash码变动



    - 更新方式
        方式一、通过set命令 
        [root@k8smaster01 ~]# kubectl set image deployment/nginx-deployment nginx=nginx:1.16
        deployment.apps/nginx-deployment image updated
        [root@k8smaster01 ~]# kubectl rollout status deployment nginx-deployment
        Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
        Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
        Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
        Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
        Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
        deployment "nginx-deployment" successfully rolled out

        方式二、通过pathch命令
        # 定位镜像的版本
        [root@k8smaster01 ~]# kubectl get deployment nginx-deployment -o=jsonpath="{.spec.template.spec.containers[*].image}"

        # 通过补丁方式更新
        [root@k8smaster01 ~]# kubectl patch deployment nginx-deployment --type='json' -p='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value":"nginx:1.19"}]'
        # "op": "replace" 表示这是一个替换操作。
        # "path": "/spec/template/spec/containers/0/image" 指定了要更新的路径，其中 containers/0 表示第一个容器（索引从 0 开始）。
        # "value":"nginx:1.19" 是新的镜像版本。

        deployment.apps/nginx-deployment patched
        [root@k8smaster01 ~]# kubectl rollout status deployment nginx-deployment
        Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
        Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
        deployment "nginx-deployment" successfully rolled out
        [root@k8smaster01 ~]# kubectl get pods -o wide
        NAME                                READY   STATUS    RESTARTS   AGE   IP             NODE            NOMINATED NODE   READINESS GATES
        nginx-deployment-7f89bcdfd4-qtwnm   1/1     Running   0          12s   10.100.1.119   k8snode01.com   <none>           <none>
        nginx-deployment-7f89bcdfd4-vq224   1/1     Running   0          9s    10.100.1.120   k8snode01.com   <none>           <none>
        nginx-deployment-7f89bcdfd4-zhs9p   1/1     Running   0          10s   10.100.2.39    k8snode02.com   <none>           <none>
        [root@k8smaster01 ~]# curl  10.100.1.119 -I
        HTTP/1.1 200 OK
        Server: nginx/1.19.10
        Date: Thu, 23 Jan 2025 05:51:50 GMT
        Content-Type: text/html
        Content-Length: 612
        Last-Modified: Tue, 13 Apr 2021 15:13:59 GMT
        Connection: keep-alive
        ETag: "6075b537-264"
        Accept-Ranges: bytes

        
        
        方式三、直接修改资源清单apply应用
        [root@k8smaster01 ~]# cat nginx-deployment.yaml
        .....
                image: nginx:1.19
        .....
        [root@k8smaster01 ~]# kubectl apply -f nginx-deployment.yaml




    - 查看更新
        更新状态：
        [root@k8smaster01 ~]# kubectl rollout status deployment nginx-deployment
        更新历史
        [root@k8smaster01 ~]# kubectl rollout history deployment nginx-deployment


    -- 回滚操作
        回滚上一版本
        [root@k8smaster01 ~]# kubectl rollout history deployment nginx-deployment
        deployment.apps/nginx-deployment
        REVISION  CHANGE-CAUSE
        1         <none>
        3         <none>
        4         <none>

        [root@k8smaster01 ~]# kubectl rollout undo deployment nginx-deployment
        deployment.apps/nginx-deployment rolled back


        回滚指定版本
        [root@k8smaster01 ~]# kubectl rollout undo deployment nginx-deployment --to-revision=1
        deployment.apps/nginx-deployment rolled back











DS资源：
    DS资源和deployment结构类似，唯独没有副本数里，DS的数量均匀分布在Node节点运行，适合日志收集、监控agent的服务选择类型。
    
    
    
DS资源实例
[root@k8smaster01 ~]# cat node-exporter.yaml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: daemonset-demo
  namespace: default
spec:
  selector:
    matchLabels:
      app: prometheus
      component: node-exporter
  template:
    metadata:
      labels:
        app: prometheus
        component: node-exporter
    spec:
      hostNetwork: true
      hostPID: true
      containers:
      - image: prom/node-exporter:v1.2.0
        name: prometheus-node-exporter
        ports:
        - name: prom-node-exp
          containerPort: 9100
          hostPort: 9100