There're 2 brokers which are configured as a cluster through network connector.
Allways, messages are sent by a producer to broker0, and consumed by a consumer of broker0. But we found that some duplicated messages are sent to broker1, even broker0 are working well.
That's say, this duplicated messages are contains in both broker0 and broker1. Could anyone tell me the reason ?
Thank you
Such kind of situation can occur, if you are trying to use two independent ActiveMQ instances in a cluster and client has been given access to both broker URLs.
The solution is to use the master-slave feature that is designed to provide high availability.
Related
Q: we want publish same message in different Activemq servers. can we have any approach. like we will publish once and activemq changes will give a forward that message to another instance.
or is there any way we can do it by the activemq config changes?
There is not much context in the question but a simple Topic together with Network of brokers should do that.
The idea is that you connect multiple brokers using "network of brokers", then messages sent to a topic will be available to all clients on all brokers throughout the network.
There are a lot of corner cases when it comes to network of brokers and topics, but it should do the work.
I would like to use MassTransmit similar to NServiceBus, every publisher and subscriber has a local queue. However I want to use RabbitMQ.
So do all my desktop clients have to have RabbitMQ installed, I think so, then should I just connect the 50 desktop clients and 2 servers into a cluster?
I know the two servers must be in the same cluster. However 50 client nodes, seems a bi tmuch to put in one cluster.....Or should I shovel them or Federate them to the server cluster exchange?
The desktop machine send messages like: LockOrder, UnLock Order.
The Servers are dealing with backend hl7 messages.
Any help and advice here is much appreciated, this is all on windows machines.
Basically I am leaving NServiceBus behind, as it is now too expensive, they aiming it at large corporations with big budgets, hence Masstransmit.
However I want reliable/durable messaging, hence local queues on ALL publishers and ALL subscribers.
The desktops also use CQS to update their views.
should I just connect the 50 desktop clients and 2 servers into a cluster?
Yes, you have to connected your clients to the cluster.
However 50 client nodes, seems a bi tmuch to put in one cluster.
No, (or it depends how big are your servers) 50 clients is a small number
Or should I shovel them or Federate them to the server cluster exchange?
The desktop machine send messages like: LockOrder, UnLock Order.
I think it's better the cluster, because federation and shovel are asynchronous, it means that your LockOrder could be not replicated in time.
However I want reliable/durable messaging, hence local queues on ALL publishers and ALL subscribers
Withe RMQ you can create a persistent queue and messages, and it is not necessary if the client(s) is connected. It will get the messages when it will connect to the broker.
I hope it helps.
I have a FOSS ESB rpoject called Shuttle, if you would like to give it a spin: https://github.com/Shuttle/shuttle-esb
I haven't used NServiceBus for a while and actually started Shuttle when it went commercial. The implementation is somewhat different from NServiceBus. I don't know MassTransit at all, though. Currently process managers (sagas) have to be hand-rolled in Shuttle whereas MassTransit and NServiceBus have this incorporated. If I do get around to adding sagas I'll be adding them as a Module that can be plugged into the receiving pipeline. This way one could have various implementations and choose the flavour you like :)
Back to your issue. Shuttle has the concept of an optional outbox for queuing technologies like RabbitMQ. Shuttle does have a RabbitMQ implementation. I believe the outbox works somewhat like 'shovel' does. So the outbox would be local and sending messages would first go to the outbox. It would periodically try to send messages on to the recipients and, after a configurable number of attempts, send the message to an error queue. It can then be returned to the outbox for further attempts, or even moved directly to the recipient queue once it is up.
Documentation here: http://shuttle.github.io/shuttle-esb/
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?
Is it possible to set up mirrored queues on different broker instances, residing on different machines? If so, how?
If not, what component(s) might I need to subclass/override to do something homegrown?
Not really sure whay your incentive is for this setup.
If you have multiple brokers in a network, you can't really tell which machine a certain message is on (since it's forwarded to the broker where there is a connected consumer).
If all you need is wiretapping to a totally different ActiveMQ server, you can use Apache Camel for that (it's included in ActiveMQ).
You just need to configure a connector to each ActiveMQ instance.
Actually, in a response to another question, I wrote a small Camel route that copies messages from every queue starting with FOO. to another queue with the name COPY.<queue name>. It might be useful in this case too.
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.