Description:

Upgraded to our Rocket Chat to version 2.0.0, this morning. When starting up the two Rocket Chat instances, I noticed several instances of this error in the logs:

Oct 2 05:44:42 chat rocketchat1: === UnHandledPromiseRejection ===
Oct 2 05:44:42 chat rocketchat1: { MongoError: ns not found
Oct 2 05:44:42 chat rocketchat1: at /opt/Rocket.Chat/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/pool.js:581:63
Oct 2 05:44:42 chat rocketchat1: at authenticateStragglers (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/pool.js:504:16)
Oct 2 05:44:42 chat rocketchat1: at Connection.messageHandler (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/pool.js:540:5)
Oct 2 05:44:42 chat rocketchat1: at emitMessageHandler (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/connection.js:310:10)
Oct 2 05:44:42 chat rocketchat1: at Socket. (/opt/Rocket.Chat/programs/server/npm/node_modules/meteor/npm-mongo/node_modules/mongodb-core/lib/connection/connection.js:453:17)
Oct 2 05:44:42 chat rocketchat1: at emitOne (events.js:116:13)
Oct 2 05:44:42 chat rocketchat1: at Socket.emit (events.js:211:7)
Oct 2 05:44:42 chat rocketchat1: at addChunk (_stream_readable.js:263:12)
Oct 2 05:44:42 chat rocketchat1: at readableAddChunk (stream_readable.js:250:11)
Oct 2 05:44:42 chat rocketchat1: at Socket.Readable.push (stream_readable.js:208:10)
Oct 2 05:44:42 chat rocketchat1: at TCP.onread (net.js:597:20)
Oct 2 05:44:42 chat rocketchat1: ok: 0,
Oct 2 05:44:42 chat rocketchat1: errmsg: 'ns not found',
Oct 2 05:44:42 chat rocketchat1: code: 26,
Oct 2 05:44:42 chat rocketchat1: codeName: 'NamespaceNotFound',
Oct 2 05:44:42 chat rocketchat1: operationTime: Timestamp { bsontype: 'Timestamp', low: 16, high: 1570013082 },
Oct 2 05:44:42 chat rocketchat1: '$clusterTime':
Oct 2 05:44:42 chat rocketchat1: { clusterTime: Timestamp { bsontype: 'Timestamp', low: 16, high: 1570013082 },
Oct 2 05:44:42 chat rocketchat1: signature: { hash: [Object], keyId: [Object] } },
Oct 2 05:44:42 chat rocketchat1: name: 'MongoError',
Oct 2 05:44:42 chat rocketchat1: [Symbol(mongoErrorContextSymbol)]: {} }
Oct 2 05:44:42 chat rocketchat1: ---------------------------------
Oct 2 05:44:42 chat rocketchat1: Errors like this can cause oplog processing errors.
Oct 2 05:44:42 chat rocketchat1: Setting EXIT_UNHANDLEDPROMISEREJECTION will cause the process to exit allowing your service to automatically restart the process
Oct 2 05:44:42 chat rocketchat1: Future node.js versions will automatically exit the process

Steps to reproduce:

1.Upgrade from 1.3.2 to 2.0.0
2. Restart the Rocket Chat instances
3. tail the logs

Expected behavior:

No mongo errors should be presented

Actual behavior:

MongoError: ns not found

Server Setup Information:

• Version of Rocket.Chat Server: 2.0.0
• Operating System: Centos 7
• Deployment Method: tar
• Number of Running Instances: 2
• DB Replicaset Oplog: enabled
• NodeJS Version: 8.11.4
• MongoDB Version: 3.6.14

Additional context

It might be interesting to add that we have two Rocket Chat instances running on this server. The services are called rocketchat1 and rocketchat2. All of the mongo errors about "ns not found" occurred on the rocketchat1 service. This did not happen on the rocketchat2 service.

Also, both services did start up. And it looks like Rocket Chat is working correctly.