Debezium Kafka connector mongodb : Error connecting kafka connector to mongodb

Question

Below are my MongoDB config in /etc/kafka/connect-mongodb-source.properties

name=mongodb-source-connector 
connector.class=io.debezium.connector.mongodb.MongoDbConnector 
mongodb.hosts=/remoteserveraddress:27017 
mongodb.name=mongo_conn 
initial.sync.max.threads=1 
tasks.max=1

but getting below error

 ERROR Plugin class loader for connector: 'io.debezium.connector.mongodb.MongoDbConnector' was not found. Returning: org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader@5a058be5 (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:165)

Running connector in standalone mode.

I have mongodbconnector class under debezium-debezium-connector-mongodb-1.0.0/debezium-connector-mongodb-1.0.0.Final.jar

also classpath is set as follows

#for CLASSPATH
CLASSPATH=/Users/111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/*
export CLASSPATH
PATH=$PATH:/usr/local/sbin
export PATH

Using plugin path I see its able to register and load all required plugins..

[2020-01-10 08:14:07,916] INFO Scanning for plugin classes. This might take a moment ... (org.apache.kafka.connect.cli.ConnectStandalone:78)
[2020-01-10 08:14:07,942] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongodb-driver-3.11.1.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,082] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongodb-driver-3.11.1.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)
[2020-01-10 08:14:08,083] INFO Added plugin 'org.apache.kafka.connect.connector.policy.AllConnectorClientConfigOverridePolicy' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,083] INFO Added plugin 'org.apache.kafka.connect.connector.policy.PrincipalConnectorClientConfigOverridePolicy' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,083] INFO Added plugin 'org.apache.kafka.connect.connector.policy.NoneConnectorClientConfigOverridePolicy' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,085] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/debezium-connector-mongodb-1.0.0.Final.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,120] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/debezium-connector-mongodb-1.0.0.Final.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)
[2020-01-10 08:14:08,121] INFO Added plugin 'io.debezium.connector.mongodb.MongoDbConnector' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,121] INFO Added plugin 'io.debezium.connector.mongodb.transforms.ExtractNewDocumentState' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,121] INFO Added plugin 'io.debezium.connector.mongodb.transforms.UnwrapFromMongoDbEnvelope' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,122] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/debezium-core-1.0.0.Final.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,198] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/debezium-core-1.0.0.Final.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)
[2020-01-10 08:14:08,198] INFO Added plugin 'io.debezium.converters.ByteBufferConverter' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,199] INFO Added plugin 'io.debezium.transforms.UnwrapFromEnvelope' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,199] INFO Added plugin 'io.debezium.transforms.ExtractNewRecordState' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,199] INFO Added plugin 'io.debezium.transforms.outbox.EventRouter' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,199] INFO Added plugin 'io.debezium.transforms.ByLogicalTableRouter' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,200] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongo-kafka-0.2-all.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,340] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongo-kafka-0.2-all.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)
[2020-01-10 08:14:08,340] INFO Added plugin 'com.mongodb.kafka.connect.MongoSourceConnector' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,340] INFO Added plugin 'com.mongodb.kafka.connect.MongoSinkConnector' (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:193)
[2020-01-10 08:14:08,341] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/bson-3.11.1.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,373] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/bson-3.11.1.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)
[2020-01-10 08:14:08,373] INFO Loading plugin from: /Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongodb-driver-core-3.11.1.jar (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:241)
[2020-01-10 08:14:08,465] INFO Registered loader: PluginClassLoader{pluginLocation=file:/Users/1111111/workspace/KafkaConnect/confluent-5.3.2/debezium-debezium-connector-mongodb-1.0.0/mongodb-driver-core-3.11.1.jar} (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:264)

but at the end again same issue

    [2020-01-10 08:40:43,613] ERROR Plugin class loader for connector: 'io.debezium.connector.mongodb.MongoDbConnector' was not found. Returning: org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader@33f2df51 (org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader:165)
[2020-01-10 08:40:43,809] ERROR Stopping after connector error (org.apache.kafka.connect.cli.ConnectStandalone:121)
java.lang.IllegalArgumentException: username can not be null
    at com.mongodb.MongoCredential.<init>(MongoCredential.java:350)
    at com.mongodb.MongoCredential.<init>(MongoCredential.java:344)
    at com.mongodb.MongoCredential.createCredential(MongoCredential.java:169)
    at io.debezium.connector.mongodb.ConnectionContext.<init>(ConnectionContext.java:69)
    at io.debezium.connector.mongodb.MongoDbConnector.validate(MongoDbConnector.java:222)
    at org.apache.kafka.connect.runtime.AbstractHerder.validateConnectorConfig(AbstractHerder.java:313)
    at org.apache.kafka.connect.runtime.standalone.StandaloneHerder.putConnectorConfig(StandaloneHerder.java:192)
    at org.apache.kafka.connect.cli.ConnectStandalone.main(ConnectStandalone.java:115)
[2020-01-10 08:40:43,810] INFO Kafka Connect stopping (org.apache.kafka.connect.runtime.Connect:66)

output of >curl localhost:8083/connector-plugins

[{"class":"com.mongodb.kafka.connect.MongoSinkConnector","type":"sink","version":"0.2"},{"class":"com.mongodb.kafka.connect.MongoSourceConnector","type":"source","version":"0.2"},{"class":"io.confluent.connect.activemq.ActiveMQSourceConnector","type":"source","version":"5.3.2"},{"class":"io.confluent.connect.elasticsearch.ElasticsearchSinkConnector","type":"sink","version":"5.3.2"},{"class":"io.confluent.connect.ibm.mq.IbmMQSourceConnector","type":"source","version":"5.3.2"},{"class":"io.confluent.connect.jdbc.JdbcSinkConnector","type":"sink","version":"5.3.2"},{"class":"io.confluent.connect.jdbc.JdbcSourceConnector","type":"source","version":"5.3.2"},{"class":"io.confluent.connect.jms.JmsSourceConnector","type":"source","version":"5.3.2"},{"class":"io.confluent.connect.replicator.ReplicatorSourceConnector","type":"source","version":"5.3.2"},{"class":"io.confluent.connect.s3.S3SinkConnector","type":"sink","version":"5.3.2"},{"class":"io.confluent.connect.storage.tools.SchemaSourceConnector","type":"source","version":"5.3.2-ce"},{"class":"io.debezium.connector.mongodb.MongoDbConnector","type":"source","version":"1.0.0.Final"},{"class":"org.apache.kafka.connect.file.FileStr

thanks in advance

score 1 · Answer 1 · answered Jan 10 '20 at 08:37

1

First of all, please check the installation of your plugin using the Kafka Connect REST Interface (see details here).

Try to install Kafka Connect plugins using the plugin path mechanism instead of CLASSPATH (more info in the docs).

answered Jan 10 '20 at 08:37

Iskuskov Alexander

4,077
3
23
38

thanks for your answer.I have tried with plugin path too, below is the path in connect-standalone.properties as well as connect-avro-standalone.properties, still same issue, it's not able to load Plugin class loader for connector: 'io.debezium.connector.mongodb.MongoDbConnector... though I see its able to register all required loaders in the start of the log from the specified location and added plugins. {plugin.path=/Users/11111111/workspace/KafkaConnect/confluent- 5.3.2/debezium-debezium-connector-mongodb-1.0.0} – user837593 Jan 10 '20 at 14:08
Try `plugin.path=/Users/11111111/workspace/KafkaConnect/confluent-5.3.2`. Your plugins should be inside `plugin.path`. E.g. if you have two plugins and `plugin.path=/opt/connectors`, path of the first plugin is `/opt/connectors/confluentinc-kafka-connect-http-1.0.3/`, the second path is `/opt/connectors/confluentinc-kafka-connect-jdbc-5.3.1/` – Iskuskov Alexander Jan 10 '20 at 14:40
@ Iskuskov Alexander - you are right, when I changed path it tries to load plugins from each directory inside confluent- 5.3.2/... however in both cases I see its able to find and load plugins from debezium, I added detailed logs in my original question.. still same issue . – user837593 Jan 10 '20 at 14:45
@user837593, please show output of `curl localhost:8083/connector-plugins` command. – Iskuskov Alexander Jan 10 '20 at 14:49
@ Iskuskov Alexander -Kafka connect stops after connector error, so port 8083 not available [2020-01-10 08:40:43,810] INFO Kafka Connect stopping (org.apache.kafka.connect.runtime.Connect:66) [2020-01-10 08:40:43,810] INFO Stopping REST server (org.apache.kafka.connect.runtime.rest.RestServer:244) – user837593 Jan 10 '20 at 14:58
But if I run same in distributed mode, and run curl command, out put is pasted in question because of char limit here – user837593 Jan 10 '20 at 15:05
I think your problem is in your config: you have to set `mongodb.user` property (see [example](https://docs.confluent.io/current/connect/debezium-connect-mongodb/index.html#start-the-debezium-mongodb-connector)). – Iskuskov Alexander Jan 10 '20 at 15:11
@user837593, tell me please did you check your config? – Iskuskov Alexander Jan 10 '20 at 16:06
Thank you so much for all your inputs. There was no issue with the config. Issue was that by default connector has source='admin' configured and the DB server I was trying to connect didn't had any admin as authentication. Seems like this is known issue. I used another test DB with no Authentication Database and that helped – user837593 Jan 11 '20 at 01:04
@user837593, great! I hope I was helpful to you! If my answer is correct, please vote up and accept it – Iskuskov Alexander Jan 11 '20 at 01:12

user837593 · Accepted Answer · 2020-01-11T12:17:47.490

1

There were two issues

Debezium connector has hardcoded source='admin'and there is no way to overwrite it and the DB server I was trying to connect didn't had any admin as authentication.
Test server that I was using was standalone server and had no replica, so I had to create replica and add this server to it. Debezium connector doesnt support standalone servers.

edited Jan 11 '20 at 12:17

answered Jan 11 '20 at 01:11

user837593

337
1
5
25

The first one (configurable auth source) has been fixed for the upcoming Debezium 1.1.0.Alpha1 release. – Gunnar Jan 14 '20 at 20:14

Debezium Kafka connector mongodb : Error connecting kafka connector to mongodb

2 Answers2