I'm investigating the usage of some message broker that does not depend on any external services. I hit upon ActiveMQ which was using replicated LevelDB and that apparently required ZooKeeper services. With ActiveMQ now switching to KahaDB, is zookeeper still required for using ActiveMQ ?
Any recommendations on what the best message broker would be, my deployment does not deal with high scale pub-sub. I'm looking for something very lightweight that can support reliable message delivery, persistent messages and HA.
I found the answer to my own question
http://activemq.apache.org/kahadb-master-slave.html
yes, even KahaDB requires zookeeper at the moment
ActiveMQ does not require ZooKeeper to run, the default store KahaDB does not have a replication feature such as that in LevelDB and so does not need any ZooKeeper instances.
For HA you might want to look into ActiveMQ Artemis which offers solutions beyond what exists in ActiveMQ proper.
Related
Is it possible to use KahaDB based persistance with network of brokers in ActiveMQ. I need to setup network of broker to mitigate risk of single point of failure with single centralized broker (master/slave).
If you do mean "network of brokers", yes, you just need to config KahaDb for each brokers, no difference with single point.
But network of brokers is different with master/slave, it is used to allow many brokers to be connected together, to provide massive scalability.
If you mean master/slave, it does not support kahadb yet, but is under review, see http://activemq.apache.org/kahadb-master-slave.html
Is not Apache Kafka another implementation of JMS?
I am using JMS+AMQ in my application, and migrating to Apache Kafka. Do I have to change all JMS codes?
No, Kafka is different from JMS systems such as ActiveMQ.
see ActiveMQ vs Apollo vs Kafka
Kafka has less features than ActiveMQ, as the stress has been put on performances. So before migrating, check that the features you use in AMQ are in Kafka.
However, there is an open suggestion for a bridge between JMS and Kafka, to allow exactly what you need. Maybe the provided links can help you
https://issues.apache.org/jira/browse/KAFKA-1995
Actually, the two are not the same. And with a little more time seeing the two co-exist - and listening to problems and happy points from those deploying each in the field - there is a little more to say about each one.
Firstly, JMS supports both point-to-point messaging (where messages are sent to single consumers; the consumers themselves maintain their message queues) and the publish-and-subscribe (pub/sub) model (where messages are written to a single topic, and consumers, independently, decide which messages to consume).
In a point-to-point messaging architecture, message producers and consumers know each other, where as in a pub/sub model they do not. Apache Kafka focuses on a pub/sub model, maintaining a separate log/topic from which consumers read from offsets. Kafka is also built for the cloud, with high-throughput a core consideration.
Many in our community and at meetups throw their hands up in frustration at MOMs (message-oriented middlewares) like JMS and switch to Kafka, for, what boils down to one reason: scalability. They argue that Kafka is better suited for scale than other MOMs because Kafka maintains a partitioned topic log. In so doing, Kafka can split up message flow to groups of consumers by partition and batch transmit the messages.
This concept also allows Kafka to have more granular control over ACLs (access control) to Kafka Consumers, although there are some issues there, which Apache Pulsar is addressing.
Finally, on Kafka, since the client/consumer decides which messages to consume (by offset in the topic), this removes some of the producer-side complexity of routing rules built into MOMs like JMS.
There's more differences than that, but this is a distillation of some of the ones that keep coming up! Hope this helps.
No, Kafka uses its own non-standard protocol and clients.
However, there's a 3rd-party JMS Client for Kafka from Confluent.
I am trying to set up cluster of brokers, which should have same feature like rabbitMQ cluster, but over WAN (my machines are in different locations), so rabbitMQ cluster does not work.
I am looking to alternatives, rabbitMQ federation is just backup the messages in the downstream, can not make sure they have exactly the same messages available at any time (downstream still keeps the old messages already consumed in the upstream)
how about ActiveMQ Master/Slave, I have found :
http://activemq.apache.org/how-do-distributed-queues-work.html
"queues and topics are all replicated between each broker in the cluster (so often to a master and maybe a single slave). So each broker in the cluster has exactly the same messages available at any time so if a master fails, clients failover to a slave and you don't loose a message."
My concern is that if it can automatically update to make sure Master/Slave always have the same messages, which means the consumed messages in Master will also disappear in Slaves.
Thanks :)
ActiveMQ has various clustering features.
First there is High Availability - "Master/Slave". The idea is that several physical servers act as a single logical ActiveMQ broker. If one goes down, another takes it place without losing data. You can do that by sharing the message store (shared file system or shared JDBC), or you could setup a replicated cluster, which replicates read/writes to the master down to all slaves (you need three+ servers). ActiveMQ is using LevelDB and Apache Zookeeper to achieve this.
The other format of cluster available in ActiveMQ is to be able to distribute load and separate security over several logical brokers. Brokers are then connected in a network of brokers. Messages are by default passed around to the broker with available consumers for that message. However, there is a rich toolbox of features in ActiveMQ to tweak a network of brokers to do things as always send a copy of a message to specific broker etc. It takes some messing with the more advanced features though (static network connectors and queue mirroring, maybe more).
Maybe there is a better way to solve your requirements, which is not really specified in the question?
Are Activemq, Redis and Apache camel a right combination?
Am planning for a high performant enterprise level integration solution accross multiple applications
My objective is to make the solution
a. independent of the consumers performance
b. able to trouble shoot in case of any issue
c. highly available with failover support
d. Hanlde 10k msgs per second
Here I'm planning to have
a. network of activemq brokers running in all app servers and storing the consumed messages in redis data store
b. from redis data store, application can retrieve the messages through camel end points
(camel end point is chosen to process the messages before reaching the app).
Also can ActiveMQ be removed with only Redis + Apache camel, as I see from the discussions forms that Redis does most of the ActiveMQ stuff
Could any one advise on this technology stack.
ActiveMQ and Camel works great together and scales very well - should be no problem to handle the load given proper hardware.
Are you thinking about something like this?
Message producer App -> ActiveMQ -> Camel -> Redis
Message Consumer App <- Camel [some endpoint] <- Redis
Puting ActiveMQ in between is usually a very good way to achieve HA, load balancing and making the solution elastic. Depending on your specific setup with machines etc. ActiveMQ can help in many ways to solve HA issues.
Removing ActiveMQ can a good option if your apps use some other protocol than JMS/ActiveMQ messaging, i.e. HTTP, raw tcp or similar. Can you elaborate on how the apps will communicate with Camel? ActiveMQ, by default, supports transactions, guaranteed delivery and you can live with a limited number of threads on the server, even for your heavy traffic. For other protocols, this might be a bit trickier to achieve. Without a HA layer (cluster) in ActiveMQ you need to setup Redis to handle HA in all aspects, which might be just as easy, but Redis is a bit memory hungry, so be aware of that.
In ActiveMQ, there is a concept called BrokerService. Normally for learning purposes, I am starting the broker from the command line using 'activemq' which starts the Broker.
What is the difference between starting the broker this way and using the BrokerService.start();
My guess is that when you use 'activemq' , the broker starts in its own jvm, when you use BrokerService.start(), the broker is using the existing JVM.
Is this correct?
Also, if someone can point to a resource that explains how the broker architecture is implemented in a traditional j2ee server like weblogic, that would be much appreciated.
I am mostly seeking clarification of how a broker can be deployed on a cluster?
Check out the ActiveMQ in action book. That is awesome and explains everything
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