I don't have any previous experience with *MQs and I'm looking to build knowledge on JMS and message queues in general. That way, I wonder whether I should start with ActiveMQ or just "ignore" it altogether and start by teaching myself Apollo. Is Apollo as feature-complete as ActiveMQ? Does it implement JMS 2.0 (I see that ActiveMQ got stuck with 1.1)? Will I be missing something really important?
Also, how does Kafka compare to these two solutions?
Best Answer
Apache ActiveMQ is a great workhorse full of features and nice stuff. It's not the fastest MQ software around but fast enough for most use cases. Among features are flexible clustring, fail-over, integrations with different application servers, security etc.
Apache Apollo is an attempt to write a new core for ActiveMQ to cope with a large amount of clients and messages. It does not have all nice and convenient feature of ActiveMQ but scales a lot better. Apache Apollo is a really fast MQ implementation when you give it a large multi-core server and thousands of concurrent connections. It has a nice, simple UI, but is not a "one-size-fits-all" solution.
It seems that there is an attempt ongoing to merge a number of ActiveMQ features with HornetQ under the name ActiveMQ Artemis. HornetQ has JMS2.0 support, so my humble guess is that it's likely to appear in ActiveMQ 6.x.
JIRA, Github
Kafka is a different beast. It's a very simple message broker intended to scale persistent publish subscribe (topics) as fast as possible over multiple servers. For small-medium sized deployments, Kafka is probably not the best option. It also has it's way to do things to achieve the high throughput, so you have to trade a lot in terms of flexibility to get high distributed throughput. If you are new to the area of MQ and brokers, I guess Kafka is overkill. On the other hand - if you have a decent sized server cluster and wonder how to push as many messages as possible through it - give Kafka a spin!