As explained in this question, we have a network of brokers consisting of three brokers on different servers.
The network connectors are configured as follows:
<networkConnectors>
<networkConnector uri="static:(ssl://broker2:61616,ssl://broker3:61616)" networkTTL="5"/>
</networkConnectors>
We are also considering to add the following parameters to the network connector as we think this might improve the behavior (due to advise on this blog post):
dynamicOnly="true"
decreaseNetworkConsumerPriority="true"
suppressDuplicateQueueSubscriptions="true"
However, it is also scary to do as we feel we do not fully understand what is happening right now and so cannot really be sure of the effect these settings will have on the behavior. The official documentation is not really clear on this (neither on this point nor many others by the way).
UPDATE:
What we want to achieve is that messages are as much as possible handled on the broker where they first arrive. Clients (as shown in the other post) are connected via Wifi, but have a fallback to 4G. In practice, we see that they regularly switch network and therefore connect to a different broker. We want to limit the traffic over the network connectors.
These settings should get you that 'prefer local' behavior you want:
decreaseNetworkConsumerPriority="true"
suppressDuplicateQueueSubscriptions="true"
Also, add messagTTL = 4 and consumerTTL = 1. This allows messages to hop around n + 1 times. (Where n is the number of brokers in your cluster). Also, consumerTTL = 1 means brokers will only see consumers from their immediate peer, and not see over multiple hops.
In your use case, drop the networkTTL setting-- messageTTl and consumerTTL replace it and give you more control over message hops and consumer awareness.
Related
I am trying to find an option in ActiveMQ (5.13) that would allow me to configure the broker with a maximum number of amqp connections from one client. The target is to prevent one malicious or malfunctioning client to consume all the connections available on the broker preventing other clients to connect.
I am aware of the possibility to set maximumConnections on the transportConnector, but, as long as I understand correctly, this is a global limit on all the connections so it would not help in this case.
Is my understanding of the maximumConnections correct?
Is there a way to configure maxConnections per client on the broker?
No, there is no such property for a per client limit in ActiveMQ. You'd first need to narrow down what you define as a single client as that can be defined differently by different people. IP Address might not work as there can be several different applications coming from a single address depending on network topology or application co-location within a single box etc.
I am using Apache ActiveMQ as a Brocker and Sensor devices continously publish data to it.
I want to write a subsriber # whih collect all data that broker listens.
Whther a client implemation can really scale for this kind of opeartion. what are the things to be considerd while making such client set up( subscriber)
thanks and regards
If a separate client subscribed to # will work will very much depend on the throughput/load levels involved and how well that client is written.
Some brokers (e.g. HiveMQ) have plugins that will do DB persistence directly at the broker level which for very high throughput situations may be better.
I have a middleware based on Apache Camel which does a transaction like this:
from("amq:job-input")
to("inOut:businessInvoker-one") // Into business processor
to("inOut:businessInvoker-two")
to("amq:job-out");
Currently it works perfectly. But I can't scale it up, let say from 100 TPS to 500 TPS. I already
Raised the concurrent consumers settings and used empty businessProcessor
Configured JAVA_XMX and PERMGEN
to speed up the transaction.
According to Active MQ web Console, there are so many messages waiting for being processed on scenario 500TPS. I guess, one of the solution is scale the ActiveMQ up. So I want to use multiple brokers in cluster.
According to http://fuse.fusesource.org/mq/docs/mq-fabric.html (Section "Topologies"), configuring ActiveMQ in clustering mode is suitable for non-persistent message. IMHO, it is true that it's not suitable, because all running brokers use the same store file. But, what about separating the store file? Now it's possible right?
Could anybody explain this? If it's not possible, what is the best way to load balance persistent message?
Thanks
You can share the load of persistent messages by creating 2 master/slave pairs. The master and slave share their state either though a database or a shared filesystem so you need to duplicate that setup.
Create 2 master slave pairs, and configure so called "network connectors" between the 2 pairs. This will double your performance without risk of loosing messages.
See http://activemq.apache.org/networks-of-brokers.html
This answer relates to an version of the question before the Camel details were added.
It is not immediately clear what exactly it is that you want to load balance and why. Messages across consumers? Producers across brokers? What sort of concern are you trying to address?
In general you should avoid using networks of brokers unless you are trying to address some sort of geographical use case, have too many connections for a signle broker to handle, or if a single broker (which could be a pair of brokers configured in HA) is not giving you the throughput that you require (in 90% of cases it will).
In a broker network, each node has its own store and passes messages around by way of a mechanism called store-and-forward. Have a read of Understanding broker networks for an explanation of how this works.
ActiveMQ already works as a kind of load balancer by distributing messages evenly in a round-robin fashion among the subscribers on a queue. So if you have 2 subscribers on a queue, and send it a stream of messages A,B,C,D; one subcriber will receive A & C, while the other receives B & D.
If you want to take this a step further and group related messages on a queue so that they are processed consistently by only one subscriber, you should consider Message Groups.
Adding consumers might help to a point (depends on the number of cores/cpus your server has). Adding threads beyond the point your "Camel server" is utilizing all available CPU for the business processing makes no sense and can be conter productive.
Adding more ActiveMQ machines is probably needed. You can use an ActiveMQ "network" to communicate between instances that has separated persistence files. It should be straight forward to add more brokers and put them into a network.
Make sure you performance test along the road to make sure what kind of load the broker can handle and what load the camel processor can handle (if at different machines).
When you do persistent messaging - you likely also want transactions. Make sure you are using them.
If all running brokers use the same store file or tx-supported database for persistence, then only the first broker to start will be active, while others are in standby mode until the first one loses its lock.
If you want to loadbalance your persistence, there were two way that we could try to do:
configure several brokers in network-bridge mode, then send messages
to any one and consumer messages from more than one of them. it can
loadbalance the brokers and loadbalance the persistences.
override the persistenceAdapter and use the database-sharding middleware
(such as tddl:https://github.com/alibaba/tb_tddl) to store the
messages by partitions.
Your first step is to increase the number of workers that are processing from ActiveMQ. The way to do this is to add the ?concurrentConsumers=10 attribute to the starting URI. The default behaviour is that only one thread consumes from that endpoint, leading to a pile up of messages in ActiveMQ. Adding more brokers won't help.
Secondly what you appear to be doing could benefit from a Staged Event-Driven Architecture (SEDA). In a SEDA, processing is broken down into a number of stages which can have different numbers of consumer on them to even out throughput. Your threads consuming from ActiveMQ only do one step of the process, hand off the Exchange to the next phase and go back to pulling messages from the input queue.
You route can therefore be rewritten as 2 smaller routes:
from("activemq:input?concurrentConsumers=10").id("FirstPhase")
.process(businessInvokerOne)
.to("seda:invokeSecondProcess");
from("seda:invokeSecondProcess?concurentConsumers=20").id("SecondPhase")
.process(businessInvokerTwo)
.to("activemq:output");
The two stages can have different numbers of concurrent consumers so that the rate of message consumption from the input queue matches the rate of output. This is useful if one of the invokers is much slower than another.
The seda: endpoint can be replaced with another intermediate activemq: endpoint if you want message persistence.
Finally to increase throughput, you can focus on making the processing itself faster, by profiling the invokers themselves and optimising that code.
Server A and B are in 2 different physical locations - There is an instance of RabbitMQ in each location. The network that connects the locations is terrible and totally unreliable. The specific requirements of the application is that messages placed on Server A queues are mirrored on Server B and vice versa.
The unreliable network seems to be wreaking havoc in terms of the reliablity of message delivery - the shovel plugin is what I am using at the moment but it appears to be dropping messages on the odd occasion. I can only assume that the message is being acked from the source queue before being properly delivered to the destination queue but there is nothing in the logs to suggest this is what is happening
Is there a better way to achieve this queue mirroring over an unreliable network like this? I have considered dropping the queue entirely and instead moving to a more synchronous approach (an http api maybe) but I'd prefer not to do that without understanding if there is a better way to achieve a mirrored queue across a flaky network connection or how I can more accurately determine what the issue is.
Shovel is designed with failure in mind. Make sure ack_mode for the shovel config is set to on_confirm. This way messages wont disappear from the source broker until fully confirmed as delivered to the destination broker. See ref
I'm trying to create a network of brokers such that there will be two 'domains' a core and a distribution. The difference between then will be that no topics published to in the distribution will be allowed to flow into core.
broker_core_primary
broker_core_secondary
broker_dist_primary
broker_dist_secondary
The message flow would be as follows:
broker_core_primary <---> broker_core_secondary
broker_dist_primary <---> broker_dist_secondary
core (broker_core_primary,broker_core_secondary) ----> dist(broker_dist_primary,broker_dist_secondary)
I've got this working with the below configs but it does not gracefully recover from the loss of any one broker and reintroduction of that broker makes things even worse.
Any help would be greatly appreciated. I'm open to changing topologies as well, so long as I can keep the concept of a separate publication domain so that topics published in dist can be blocked from consumption on core brokers.
broker_core_primary
broker_core_secondary
broker_core_primary" duplex="true" networkTTL="5" uri="static:(tcp://broker_core_primary:61616)?maxReconnectDelay=5000,useExponentialBackOff=false,randomize=false,trace=true" userName="brokerBridge" password="REMOVED" />
broker_dist_primary
broker_core" duplex="false" networkTTL="5" uri="static:(tcp://broker_core_primary:61616,tcp://broker_core_secondary:61616)?maxReconnectDelay=5000,useExponentialBackOff=false,randomize=false,trace=true" userName="brokerBridge" password="REMOVED" />
broker_dist_secondary
broker_core" duplex="false" networkTTL="5" uri="static:(tcp://broker_core_primary:61616,tcp://broker_core_secondary:61616)?maxReconnectDelay=5000,useExponentialBackOff=false,randomize=false,trace=true" userName="brokerBridge" password="REMOVED" />
broker_dist_primary" networkTTL="5" duplex="true" uri="static:(tcp://broker_dist_primary:62626)?maxReconnectDelay=5000,useExponentialBackOff=false,randomize=false,trace=true"
userName="brokerBridge" password="REMOVED">
please define "not gracefully recover"
just some possible mistakes:
your producers and consumers need to be aware of all cluster node
for a network of 4 brokers in (basicly) a hypercube ttl 5 is overkill and could have unwanted effects
a different way of blocking destinations from publication to connected network nodes is to exclude them in config. excluded (or included) destinations would be configured on the network connectors (see the documentation)
ps: please format your questions better and use real xml from your config, its really hard to read.