本地mongo停止时，Express无法连接到mongodb副本集

Question

I have a mongodb replica set with the following config:

• M1 (192.168.77.3) primary (host App1)
• M2 (192.168.77.4) secondary (host App2)
• M3 (192.168.77.5) secondary (host App3)
• M4 arbitrator

Here is my Express code to connect to db (I use mongoose as the ODM):

 const config = {
    db: `mongodb://192.168.77.3,192.168.77.4,192.168.77.5/mydb`,
    dbOptions: {
      useMongoClient: true,
      reconnectTries: Number.MAX_VALUE,
      replicaSet: process.env.REPLICA_SET,
      poolSize: 100,
      keepAlive: 1,
      connectTimeoutMS: 30000,
      socketTimeoutMS: 300000,
      w: 1
    }
  }
mongoose.connect(config.db, config.dbOptions, (error) => {
  if (error) {
    console.log('Error on connecting to th db: ', error)
    console.log('\x1b[31m', '*** PLEASE CONNECT TO DATABASE BEFORE RUN SERVER', '\x1b[0m')
    process.exit(1)
  }
  callback()
})

The app works as expected. When M1 get down, either M2 or M3 get elected to be the primary , the App2 and App3 still working, BUT the App1 CAN'T connect to the replica set with the error message:

MongoError: failed to connect to server [localhost:27017] on first connect [MongoError: connect ECONNREFUSED 127.0.0.1:27017]

This is my mongodb config on App1 :

storage:
  dbPath: /var/lib/mongodb
  journal:
    enabled: true

systemLog:
  destination: file
  logAppend: true
  path: /var/log/mongodb/mongod.log

net:
  port: 27017
  bindIp: [127.0.0.1, 192.168.77.3]

replication:
  oplogSizeMB: 3000
  replSetName: my_rs

Is there any wrong in my config?

Answer 1

You CAN NOT mix IP-addresses of multiple nodes at one single config file.

Your bindIp string

bindIp: [127.0.0.1, 192.168.77.4, 192.168.77.5]

should be

bindIp: "127.0.0.1,192.168.77.3"

at first node and

bindIp: "127.0.0.1,192.168.77.4"

at second node. And so on... So, you can have localhost bind and other addresses what belong to that node.

My initial answer was wrong because I thought that it has something to do with mongooos, what I don't know.