[druid-user] MySQL metadata connector returning Java Exception Error

I’ve been trying to connect MySQL database to Druid, so I can ingest from it.
The common properties are configured correctly, as far as I can tell.
I’m new to it, some light will be great.
When I enable “mysql-metadata-storage”, Druid UI return that error:
Unknown exception / org.apache.druid.java.util.common.IOE: No known server / java.lang.RuntimeException.

Sometimes its error 500 or 400. Each time I restart druid the error change.

Also, router log give me this error:

ERROR [CoordinatorRuleManager-Exec–0] org.apache.druid.server.router.CoordinatorRuleManager - Exception while polling for rules

Also, another issue. When I try to configure Druid Basic Security, so I can connect it to superset, Druid’s UI wont even load. I keep getting connection refused. I would like some help with it as well.
PS: There is no “druid-basic-security” on extension list, because I removed, just so I could connect in the website, but it was there.

Here is my common.propertie file:

Extensions specified in the load list will be loaded by Druid

We are using local fs for deep storage - not recommended for production - use S3, HDFS, or NFS instead

We are using local derby for the metadata store - not recommended for production - use MySQL or Postgres instead

If you specify druid.extensions.loadList=[], Druid won’t load any extension from file system.

If you don’t specify druid.extensions.loadList, Druid will load all the extensions under root extension directory.

More info: https://druid.apache.org/docs/latest/operations/including-extensions.html

druid.extensions.loadList=[“druid-hdfs-storage”, “druid-kafka-indexing-service”, “druid-datasketches”, “mysql-metadata-storage”]

If you have a different version of Hadoop, place your Hadoop client jar files in your hadoop-dependencies directory

and uncomment the line below to point to your directory.


Do you want to inject from mysql or use mysql as metadata storage?

I replied in the wrong place, sorry.
I wanted to ingest from MySQL withou having to export databases or use local disk. Is it possible to query from MySQL tables inside Druid?

Issue solved.
The extension mysql-metadata-storage was breaking druid apart. I still dont know what was causing that. Maybe some version incompatibility.
Anyways, after I removed it, druid started working again, with basic security authentication working as well. Thanks.

IMO it broke druid because you configured metadata storage in both derby and MySQL.

Metadata storage (config & extension) is only to store druid metadata, not to ingest from this database.

When I posted my common.properties, I was testing with the databases, but at first, derby connection settings was commented. Thank you for the reply