I had a KafkaProducer working fine in 0.9.0.1. I was having unrelated problems in that version so thought to try 0.10.1.0. I built it as I did 0.9.0.1:
Fresh build against Scala 2.11.7. Built the tgz build plus local maven install. From the tgz I created a Docker image similar to spotify/kafka. I linked my producer code to the maven jars. This process worked in 0.9.
At the bottom you can see a clip from the output... there's a warning about metadata (not sure if its important or not) and then its trying to send() messages and timing out. I clipped the output, but it does fail the same way for each message sent in 0.10.1.0. Same code compiled against 0.9.0.1 populates the topic's partitions w/o problem.
Was there a breaking change between 0.9 and 0.10, or is this a bug?