I am wanting to setup RabbitMQ as a two (or more) node cluster with HA.
Use case: a client producer app (C#.NET) knows that the cluster has two nodes and publishes to the cluster. Various consumer apps (also C#.NET) connect to the cluster and get all messages generated by the producer. So long as at least one node is up and running the producer and consumers will all continue to work without error. Supposing nodes A and B are running and B dies for a while, then gets restarted, then a while later A dies, the clients all continue to function without receiving an error since at all times at least one node is up.
Can it be made to work like this out of the box?
Are there any other MQs that would be more appropriate (commercial ok) for a Windows/.NET application environment?
RabbitMQ v2.6.0 now supports high-availability queues using active/active clustering. Microsoft and a number of other companies have collaborated on Apache QPid which has C# bindings and which also supports active/active HA clustering.
Can it be made to work like this out of the box?
No. When a node goes down, all of its connections are closed. Since AMQP connections are stateful, there's no way around this. What you could achieve is 1) broker goes down, 2) all clients disconnect, 3) clients connect to other node (masquerading as original) and are none the wiser.
On a side note, rabbit does not support active-active HA clustering at the moment. It does support active-passive clustering and a form of logical clustering (which might be what you're looking for).
Related
I feel like I am missing something very fundamental here.
I can bring up a RabbitMQ cluster with three nodes (rabbit1, rabbit2 and rabbit3) without an issue. Then when I start writing my microservices it seems like each client connects to only one rabbit instance. So let's say I have all my services connect to rabbit1.
If rabbit1 then goes down will my entire infrastructure blow up? Do the services have a way of switching to another rabbit node? It seems like they cannot, in which case, what is the point of having a cluster?
In case someone else runs into this and has trouble (like myself) finding this in the documentation, RabbitMQ does not manage client connection auto-recovery. From the docs:
Some client libraries provide a mechanism for automatic recovery from
network connection failures... Other clients may consider network
failure recovery to be a responsibility of the application.
So first check if you library offers auto-recovery, if not you'll have to implement it yourself.
We have been having below issues from RabbitMQ and had been manually restarting the servers every weekend as a work around.
Network partition detected
Mnesia reports that this RabbitMQ cluster has experienced a network partition. This is a dangerous situation. RabbitMQ clusters should not be installed on networks which can experience partitions.
We have gone through other popular posts on the topic e.g. here and here
Our network is not highly reliable and occasional blips are expected but when it does come up I would have expected 1 of the 4 node RabbitMQ cluster to join the rest of cluster - as is the case with 4 nodes of Tomcat installed on same servers.
Although the nodes on single partition continue to run independently but doesnt seem like that is a graceful recovery from failure in one node.
We didnt have great luck with using any rabbitmqctl commands like rabbitmqctl cluster_status - It used to sporadically cause the rabbitmq process to hang which needed a sudo kill to RabbitMQ process.
We are at a point of evaluating moving to Kafka or any other message broker that handles message partition well
Any thoughts on working around not needing manual RabbitMQ restarts or ability of Kafka to handle such situation is highly appreciated
I think Kafka with replication should be able to handle network partitions quite easily, as long as the number of brokers partitioned is inferior to the replication factor of your topic (aka, the consumers and producers can always reach at least 1 broker for the topics they're operating with).
To avoid backpressure in the clients while Zookeeper discover the partition and propagate the information to the producers and consumer, you may want to set short ZK heartbeating (yes, you'll need ZK, and a cluster too since you absolutely don't want your whole ZK cluster partitioned).
Fair warning though : using a cluster of kafka brokers will drop the FIFO aspect of your message queue which can be pretty disturbing if you're expecting the same order of messages produced by the producers and read by the consumers, which you could expect with RabbitMQ.
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?
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.