本地K8s部署Prisma连接MongoDB报错：需以副本集运行

在本地Kubernetes环境部署Prisma后，尝试通过其他Pod连接MongoDB时出现如下报错：

"Prisma需要执行事务，这要求你的MongoDB服务器以副本集模式运行。"

完整报错日志：

PrismaClientKnownRequestError: 
[be-auth] 对 `prisma.user.create()` 的调用无效，位置在
[be-auth] /usr/src/app/src/routes/signup.ts:38:36
[be-auth] 
[be-auth]   35 
[be-auth]   36 const hashedPassword = await Password.toHash(password);
[be-auth]   37 
[be-auth] → 38 const user = await prisma.user.create(
[be-auth] Prisma需要执行事务，这要求你的MongoDB服务器以副本集模式运行。
[be-auth]     at zr.handleRequestError (/usr/src/app/node_modules/@prisma/client/runtime/library.js:122:8308)
[be-auth]     at zr.handleAndLogRequestError (/usr/src/app/node_modules/@prisma/client/runtime/library.js:122:7697)
[be-auth]     at zr.request (/usr/src/app/node_modules/@prisma/client/runtime/library.js:122:7307) {
[be-auth]   code: 'P2031',
[be-auth]   clientVersion: '5.0.0',
[be-auth]   meta: {}
[be-auth] }

当前MongoDB的部署YAML：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: be-auth-mongo-depl
spec:
  replicas: 1
  selector:
    matchLabels:
      app: be-auth-mongo
  template:
    metadata:
      labels:
        app: be-auth-mongo
    spec:
      containers:
        - name: be-auth-mongo
          image: mongo

---
apiVersion: v1
kind: Service
metadata:
  name: be-auth-mongo-srv
spec:
  selector:
    app: be-auth-mongo
  ports:
    - name: db
      protocol: TCP
      port: 27017
      targetPort: 27017

Prisma依赖MongoDB的事务能力，单实例MongoDB不支持该特性，必须配置为副本集。即使是本地测试环境，也需要把单实例MongoDB伪装成单节点副本集来满足要求。

修改后的MongoDB部署配置 #

apiVersion: apps/v1
kind: Deployment
metadata:
  name: be-auth-mongo-depl
spec:
  replicas: 1
  selector:
    matchLabels:
      app: be-auth-mongo
  template:
    metadata:
      labels:
        app: be-auth-mongo
    spec:
      containers:
        - name: be-auth-mongo
          image: mongo
          # 启动时指定副本集参数
          command: ["mongod"]
          args: ["--replSet", "rs0", "--bind_ip_all"]
          # 挂载初始化脚本，启动后自动初始化副本集
          volumeMounts:
            - name: init-script
              mountPath: /docker-entrypoint-initdb.d
      volumes:
        - name: init-script
          configMap:
            name: mongo-init-config

---
# 定义副本集初始化脚本的ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: mongo-init-config
data:
  init-replica-set.js: |
    rs.initiate({
      _id: "rs0",
      members: [
        { _id: 0, host: "be-auth-mongo-srv:27017" }
      ]
    })

---
apiVersion: v1
kind: Service
metadata:
  name: be-auth-mongo-srv
spec:
  selector:
    app: be-auth-mongo
  ports:
    - name: db
      protocol: TCP
      port: 27017
      targetPort: 27017

操作步骤 #

1. 删除原有MongoDB部署和服务：

kubectl delete deployment be-auth-mongo-depl
kubectl delete service be-auth-mongo-srv

2. 应用修改后的配置文件：

kubectl apply -f <你的配置文件路径>

3. 验证副本集状态：
   等待Pod启动完成后，进入Mongo容器：

kubectl exec -it $(kubectl get pods -l app=be-auth-mongo -o jsonpath="{.items[0].metadata.name}") -- mongo

在Mongo Shell中执行以下命令，若返回"ok" : 1则说明副本集初始化成功：

rs.status()

4. 更新Prisma连接字符串，指定副本集名称：
   将连接字符串修改为：

mongodb://be-auth-mongo-srv:27017/你的数据库名称?replicaSet=rs0

内容的提问来源于stack exchange，提问作者Manel