【K8s】使用StatefulSet部署有状态应用

偏执的太偏执、 2023-08-17 17:05 22阅读 0赞

**0.准备三个持久化磁盘**

[root@m-xxx ~]# ifconfig | head -2| tail -1|awk 'print{$2}'
    192.168.1.11
    [root@m-xxx ~]# echo '/net/pet1 *(rw,no_root_squash)' >> /etc/export
    [root@m-xxx ~]# echo '/net/pet2 *(rw,no_root_squash)' >> /etc/export
    [root@m-xxx ~]# echo '/net/pet3 *(rw,no_root_squash)' >> /etc/export
    [root@m-xxx ~]# systemcel restart nfs-server
    [root@m-xxx ~]# shoumount -e 192.168.1.11 # 验证

**1.创建三个持久卷(pv-a、pv-b、pv-c)**

---
      apiVersion: v1
      kind: PersistentVolume
      metadata:
        name: pv-a|pv-b|pv-c
      spec:
        capacity:
          storage: 1Gi
        accessModes: 
        - ReadWriteOnce
        - ReadOnlyMany
       #persistentVolumeReclaimPolicy: Retain # 当声明被释放，pv将保留(不清理和删除)
        persistentVolumeReclaimPolicy: Recycle # 当声明被释放，空间将回收再利用
        nfs:
          server: 192.168.1.11
          path: /net/pet1 | /net/pet2| /net/pet3

**2.创建headless Service，让pod彼此发现**  
**原理：** `kubernetes允许客户通过DNS查找发现pod IP，默认情况下，执行服务的DNS查找时，DNS服务会返回集群ip(clusterIP)，当clusterIP属性为none时，将返回pod IP而不是单个服务IP。所以客户会得到该服务旗下所有pod ip。`  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4OTAwNTY1_size_16_color_FFFFFF_t_70]

---
      apiVersion: v1
      kind: Service
      metadata:
        name: kubia-headless
      spec:
        clusterIP: None
        ports:
        - port: 80
          targetPort: 8080
        selector:
          app: kubia

**3.创建StatefulSet应用**

apiVersion: apps/v1beta1
    kind: StatefulSet
    metadata:
      name: kubia
    spec:
      serviceName: kubia
      replicas: 2
      template:
        metadata:
          labels:
            app: kubia
        spec:
          containers:
          - name: kubia
            image: kubia-pet
            ports:
            - name: http
              containerPort: 8080
            volumeMounts:
            - name: data
              mountPath: /var/data
      volumeClaimTemplates:
      - metadata:
          name: data
        spec:
          resources:
            requests:
              storage: 1Mi
          accessModes:
          - ReadWriteOnce

**4.新建centos Pod容器，并安装bind-utils作测试**

4.1得到两个Pod ip

[root@centos /]# nslookup kubia-headless 
    ...
    Name:   kubia-headless.default.svc.cluster.local
    Address: 10.244.1.61
    Name:   kubia-headless.default.svc.cluster.local
    Address: 10.244.2.80

4.2开始两个Pod均无记录

[root@centos /]# curl 10.244.1.61:8080
    You've hit kubia-0
    Data stored on this pod: No data posted yet
    [root@centos /]# curl 10.244.2.80:8080
    You've hit kubia-1
    Data stored on this pod: No data posted yet

4.3往kubia-0插入数据

[root@centos /]# curl -X POST -d "Hey there! This greeting was submitted to kubia-0." 10.244.1.61:8080

4.4再次验证，kubia-0与kubia-1独享各自状态

[root@centos /]# curl 10.244.1.61:8080
    You've hit kubia-0
    Data stored on this pod: Hey there! This greeting was submitted to kubia-0.
    [root@centos /]# curl 10.244.2.80:8080
    You've hit kubia-1
    Data stored on this pod: No data posted yet

4.5删除kubia-0，再次查看重新调度kubia-0

[root@m-xxx~ ]# kubectl delete po kubia-0
    [root@centos /]# curl 10.244.1.61:8080
    You've hit kubia-0
    Data stored on this pod: Hey there! This greeting was submitted to kubia-0.

状态正常

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