为Kubernetes部署中的每个副本绑定不同的持久卷 [英] Bind different Persistent Volume for each replica in a Kubernetes Deployment

问题描述

我正在使用具有ReadWriteOnce访问模式的PVC，由logstash部署使用它将运行有状态的应用程序并使用此PVC.部署中的每个pod都将尝试绑定到相同的持久卷声明.如果副本数> 1，它将失败(因为它支持ReadWriteOnce，因此只有第一个能够成功绑定).如何指定将每个吊舱绑定到单独的PV.

I am using a PVC with ReadWriteOnce access mode, which is used by a logstash Deployment which will run a stateful application and use this PVC.Each pod in the deployment will try to bind to the same persistent volume claim. In case of replicas > 1, it will fail (as it supports ReadWriteOnce, only the first one will be able to bind successfully). How do I specify that each pod is to be bound to a separate PV.

我不想为每个logstash副本/实例定义3个单独的Yaml

I don't want to define 3 separate yamls for each logstash replica / instance

apiVersion: apps/v1
kind: Deployment
metadata:
  name: logstash
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: logstash
    spec:
      containers:
        image: "logstash-image"
        imagePullPolicy: IfNotPresent
        name: logstash
        volumeMounts:
        - mountPath: /data
          name: logstash-data
      restartPolicy: Always
      volumes:
      - name: logstash-data
        persistentVolumeClaim:
          claimName: logstash-vol

需要一种将不同PV批量安装到不同Pod副本的方法.

Need a way to do volume mount of different PVs to different pod replicas.

推荐答案

使用部署，您将无法正确执行此操作.您应该将StatefulSet与PVC模板一起使用以实现目标.您的StatefulSet YAML代码段的一部分可能看起来像这样:

With Deployments you cannot do this properly. You should use StatefulSet with PVC template to achieve your target. The part of your StatefulSet YAML code snippet could look like this:

...
volumeClaimTemplates:
- metadata:
    name: pv-data
  spec:
    accessModes: 
      - ReadWriteOnce
    resources:
      requests:
        storage: 5G

假设您有3个副本，您会看到按顺序依次创建容器，并且在容器创建期间请求了PVC.

assuming you have 3 replicas, you will see the pods are created one by one sequentially, and the PVC is requested during the pod creation.

PVC被命名为 volumeClaimTemplate name + pod-name + ordinal number，因此，您将拥有新创建的PVC的列表:

The PVC is named as volumeClaimTemplate name + pod-name + ordinal number and as result, you will have the list of newly created PVCs:

pv-data-<pod_name>-0
pv-data-<pod_name>-1
pv-data-<pod_name>-N

StatefulSet使Pod的名称(不仅是实际上的名称)变为静态，并根据副本数对其进行递增，这就是每个Pod分别匹配其自己的PVC和PV的原因

StatefulSet makes the names (not only names in fact) of your pods static and increments them depending on replica count, thats why every Pod will match its own PVC and PV respectively

注意:这称为动态预配置.你应该熟悉 配置kubernetes控制平面组件(例如 控制器-经理)来实现这一目标，因为您将需要 配置的持久性存储(其中之一)提供程序并了解 您数据的保留政策，但这完全是另一回事 问题...

Note: this is called dynamic provisioning. You should be familiar with configuring kubernetes control plane components (like controller-manager) to achieve this, because you will need configured persistent storage (one of them) providers and understand the retain policy of your data, but this is completely another question...

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