title: Authentication failed when connected to mongodb by debezium mongodb connector
body: <p>Deployed the Strimzi Kafka, Strimzi Zookeeper and Debezium mongodb connector, and configured the Debezium mongodb,</p>
  
  <pre><code>curl 'http://my-connect-cluster-connect-api:8083/connectors' -X POST -i -H "Content-Type:application/json" -d '{
    "name": "mongodb-connector", 
    "config": {
      "connector.class": "io.debezium.connector.mongodb.MongoDbConnector",
      "mongodb.hosts": "MainRepSet/mongod-0.mongodb-service.kafka.svc.cluster.local:27017,mongod-1.mongodb-service.kafka.svc.cluster.local:27017,mongod-2.mongodb-service.kafka.svc.cluster.local:27017", 
      "mongodb.name": "MainRepSet", 
      "collection.whitelist": "springdatabase[.]*",
      "mongodb.user": "springuser",
      "mongodb.password": "password"
    }
  }'
  </code></pre>
  
  <p>But got the authentication exception,</p>
  
  <pre><code>2019-01-29 13:13:40,170 ERROR Error while reading the 'shards' collection in the 'config' database: Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=mongod-2.mongodb-service.kafka.svc.cluster.local:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSecurityException: Exception authenticating MongoCredential{mechanism=null, userName='springuser', source='admin', password=&lt;hidden&gt;, mechanismProperties={}}}, caused by {com.mongodb.MongoCommandException: Command failed with error 18: 'Authentication failed.' on server mongod-2.mongodb-service.kafka.svc.cluster.local:27017. The full response is { "operationTime" : { "$timestamp" : { "t" : 1548767616, "i" : 1 } }, "ok" : 0.0, "errmsg" : "Authentication failed.", "code" : 18, "codeName" : "AuthenticationFailed", "$clusterTime" : { "clusterTime" : { "$timestamp" : { "t" : 1548767616, "i" : 1 } }, "signature" : { "hash" : { "$binary" : "M7qA9dMzPj1sC8lfT681vT57oPw=", "$type" : "00" }, "keyId" : { "$numberLong" : "6651444731228192769" } } } }}},
  </code></pre>
  
  <p>And the mongodb account I created by below statement,</p>
  
  <pre><code>db.createUser({user:"springuser",pwd:"password",roles:[{role:"readWrite",db:"springdatabase"}]})
  </code></pre>
  
  <p>After analyze the exception, the Debezium mongodb authSource is used by default "source='admin'", but the authSource of my mongodb account is 'springdatabase', I think it is the reason the authentication failed.</p>
  
  <p>The one of the workaround is to create the mongodb account by using default 'admin'. But our production mongodb account already created, so we cannot change it. </p>
  
  <p>So is there any configuration property to set up 'authSource'?</p>