mongodb - 无法在 Kubernetes 中创建 Mongo 复制集

Question

我想在 Kubernetes 中创建一个 3 节点的 Mongo 副本集。我创建了一个 headless 服务，如下所示

apiVersion: v1
kind: Service
metadata:
  name: mongo
  labels:
    name: mongo
spec:
  ports:
  - port: 27017
    targetPort: 27017
  clusterIP: None
  selector:
    role: mongo

我还创建了一个 3 节点状态集，如下所示 -

apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: mongo
spec:
  serviceName: "mongo"
  replicas: 3
  template:
    metadata:
      labels:
        role: mongo
        environment: test
    spec:
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongo
          image: mongo
          command:
            - mongod
            - "--replSet"
            - rs0
            - "--smallfiles"
            - "--noprealloc"
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-persistent-storage
              mountPath: /data/db
          resources:
            limits:
              cpu: 500m
              memory: 512Mi
            requests:
              cpu: 400m
              memory: 256Mi
  volumeClaimTemplates:
  - metadata:
      name: mongo-persistent-storage
      persistentVolumeClaim:
        claimName: fast
    spec:
      accessModes: [ "ReadWriteMany" ]
      resources:
        requests:
          storage: 10Gi

我已经创建了有状态集，并且 pod 已启动并正在运行。现在，如果我登录到其中一个容器并在 mongo shell 中设置复制集的配置，我会收到错误消息。我输入的命令是 -

> config = {
... "_id" : "rs0",
... "members" : [
...   {
...     _id: 1,
...     host: 'mongo-0.mongo.demo.svc.cluster.local:27017'
...   },
...   {
...     _id: 2,
...     host: 'mongo-1.mongo.demo.svc.cluster.local:27017',
...   },
...   {
...     _id: 3,
...     host: 'mongo-2.mongo.demo.svc.cluster.local:27017'
...   }
... ]
... }

> rs.initiate(config)

当我执行以下操作时，出现以下错误 -

"errmsg" : "replSetInitiate quorum check failed because not all proposed set members responded affirmatively: mongo-1.mongo.demo.svc.cluster.local:27017 failed with Connection refused, mongo-2.mongo.demo.svc.cluster.local:27017 failed with Connection refused"
"code" : 74,
"codeName" : "NodeNotFound",

我不知道如何调试它，因为容器已启动并正在运行。有人可以帮我吗？谢谢

Answer 1

如果您查看任何 Pod 的日志，您将看到一条警告:

[initandlisten] ** WARNING: This server is bound to localhost.
[initandlisten] ** Remote systems will be unable to connect to this server.

因此，您必须提供 "--bind_ip" 标志以确保 MongoDB 监听来自已配置地址上的应用程序的连接。在 official mongodb doc. 中查看有关 ip 绑定(bind)的更多信息

修正后，改进后的yaml如下:

apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: mongo
spec:
  ---
  template:
    ---
    spec:
      ---
      containers:
         - ---
          command:
            - mongod
            - "--replSet"
            - rs0
            - "--bind_ip" # Add these two 
            - 0.0.0.0     # lines...!!
            - "--smallfiles"
            - "--noprealloc"
     ---
---

而且，Host DNS 也需要稍作修改。该服务部署在 default 命名空间中，而不是在 demo 中。因此，正确的配置将是:

> config = {
 "_id" : "rs0",
 "members" : [
   {
     _id: 1,
     host: 'mongo-0.mongo.default.svc.cluster.local:27017'
   },
   {
     _id: 2,
     host: 'mongo-1.mongo.default.svc.cluster.local:27017',
   },
   {
     _id: 3,
     host: 'mongo-2.mongo.default.svc.cluster.local:27017'
   }
 ]
}