I've regarded RabbitMQ as a secret weapon in plain sight for years. The killer reason people don't use it more is it "doesn't scale" to truly enormous sizes, but for anyone with less than a million users it's great.
Too many people end up with their own half rolled pubsub via things like grpc, and they'd be far better off using this, particularly in the early stages of development.
It's an infinitely more friendly version of Kafka, pub/sub, etc that is extremely lightweight. Yet every environment trends towards Kafka because it was "chosen" by the big corps.
I've used both and NATS is definitely what I'd pick starting out. RabbitMQ is great too, but its heavier and harder to configure. Federation is the killer feature of RabbitMQ that NATS doesn't really have (afaik?).
Big corps choose these bloated and complex tools because this way they can justify charging their customers premium and also that their customers won't be able to service such software on their own.
It's nothing to do with these apps being superior in any way - often it is the opposite - like reasonable faults and glitches can add more hours to bill the customers for "fixing".
I agree. NATS is much more simplistic to use and deploy. Easy to run locally for development. Jetstream offers useful features like persistent streams, and kv and object stores.
Modern RabbitMQ scales well. RabbitMQ Streams provide a throughput of millions of messages per second. With native support for MQTT, more than a million users can connect to RabbitMQ: https://www.rabbitmq.com/blog/2023/03/21/native-mqtt
The new Khepri metadata store in RabbitMQ 4.0 allows for even better scalability.
Is there a big advantage over Redis? Just coming from the Ruby world I know Sidekiq is extremely popular as a Redis backed queue. I know there's a RabbitMQ backed queue called Sneakers that's gained a lot of popularity as well though.
Just wondering what the biggest selling points are for somebody making a decision?
We switched from a redis backed queue (bullmq) to rabbit at our company (https://github.com/laudspeaker/laudspeaker) when we hit speed issues . We found bull had a much lower throughput, after a lot of tuning compared even to rabbit out of the box.
We needed features like job priorities, and complex routing logic and on top of that our software needs to send millions of messages a minute. What we miss is a nice UI to see the state of jobs, and monitor for problems more easily like: https://taskforce.sh/
At my current place, using Redis with celery is becoming bottleneck for number of concurrent connections it can hold. We are using 1000 workers and start seeing issues (ceiling is 10k connections in Redis); apparently Celery creates huge number of connections. We are considering moving to RabbitMQ for same reason.
Been a while since I last used, but IIRC Rabbit is much more featureful than Redis, and has built-in much of what you'd get from Redis + Sidekiq. Their concepts[1] docs provides a good overview. This may be too broad a stroke but what I liked best about it was we used it for our centralized pub sub system, and although we had services in multiple languages / frameworks, they connected to each other through Rabbit, which saved us from having to setup a bunch of different / incompatible job processing systems. Like Redis its battle tested so you know what you are getting complexity / scale wise. At my current gig we use the typical Rails / Sidekiq setup and though it works fine I definitely find myself missing Rabbit. (But in my head Redis / Rabbit have only some overlap, and seeing both at the same company would seem totally normal)
I think people don't use it more because people don't really know what it is. From their website:
> RabbitMQ is a reliable and mature messaging and streaming broker, which is easy to deploy on cloud environments, on-premises, and on your local machine.
What does that mean? "Messaging and streaming broker"? I understand the need for worker queues to process videos, images, emails and such but I can't easily tell if that's what this is.
Also, what are the benefits of this over just processing incomplete records straight out of my database? i.e. using MySQL as a queue.
> what are the benefits of this over just processing incomplete records straight out of my database? i.e. using MySQL as a queue
Mainly throughput and latency. I haven’t used MySQL recently so some of this may apply more to Postgres.
Postgres has LISTEN/NOTIFY which helps with latency. I don’t think MySQL has LISTEN/NOTIFY, which means you’d have to resort to polling.
You have to use the `SELECT … FOR UPDATE SKIP LOCKED LIMIT 1` features to grab a message from the queue table, so multiple consumers don’t pull the same message.
The biggest issue, if you’re trying to achieve decent throughput, is dealing with bloat (empty pages still sitting on the disk that haven’t been cleaned up yet). You can run vacuum but an online vacuum will only mark the pages as available for reuse (doesn’t free up the disk space). And if you run a full vacuum (which will free the disk space) it locks the entire database while it runs the vacuum. This can compound if you’re using indexes.
One way of dealing with this is setting up partitioning by message timestamp, so that as old messages roll out, you can just drop those partitions and not have to deal with vacuum.
It can work if your queue needs are low throughput or can tolerate higher latency, but there are some things to manage, and realistically setting up a Redis instance is probably less complex than trying to work around the database-specific quirks, unless you’re already very familiar with your database’s inner workings.
If you are looking at RabbitMQ with "Maybe this is too much". Beanstalkd likely has features you need with almost none of the setup. Just don't web expose it ;)
Be careful with it, it will segfault randomly and there hasn't been a fix.
After hitting my own posts on the Google groups while sleepily debugging the segfault at wee hours of the morning and getting falsely excited about the possibility of a fix, I gave up and wrote a replacement: https://github.com/chronomq/chronomq
Have been running it for years without it falling over, submillisecond operations on average, and has processed billions of messages without failing.
It's the polar opposite of RabbitMQ. It's a single binary written in C, you start it, you send text messages via TCP so writing a client or tooling is dead simple.
I agree, but there are a lot of footguns with RMQ. A great example of one is that you'll slow down your cluster by adding more RMQ servers (something that's bit us in the past). Which is a forgivable mistake as most people would expect that more cores == faster RMQ. (For RMQ, that doesn't work because Durable messages need to be replicated to the other nodes in the cluster. More nodes == more replication)
The ideal RMQ cluster has 3 servers and is dedicated to just a few apps.
Agreed. I ran a log ingestion infra 8 years ago doing 20k msg/s sustained on RabbitMQ ... back then we went through a lot of instabilities though they settled over time with new releases. Great times. Besides a quality product the development/release process was very professional and mature.
The biggest issue back then was finding a quality client implementation for the language you were using. Not sure what the status of that is these days.
AMQP and MQTT are both industry standard protocols. Also, RabbitMQ allows you to abuse the limits set by these standards.
Its unfortunate your team ran into performance issues, as Erlang can be inefficient in some situations. Were you using static routes on the DNS load balanced parallel consumers, or relying on the disk caching mechanisms?
For me the killer feature of Kafka is that topics are persistent until the data expires. Meaning different readers can be working at different offsets. And you can rewind or fast forward the offset you are reading, which can really be a life saver when things go sideways.
Do you have any recommended resources to learn how to apply these tools (RabbitMQ, Nats, etc) to typical enterprise services? Common patterns/usecases/best practices and things?
The anti-pattern to be avoided is cobbling together a nonperformant grand centralized ESB and making it a SPoF and bottleneck for everything, but it depends entirely on the use-case. MQTT scales to millions of devices for low data rates. ZK works well for little bits of coherent distributed cluster metadata. Kafka has its niches. ZMQ helps in others.
I've seen it used for a company with way, way in excess of a million users. We used it for a system with 100M+ users for our login systems and in general all of our main account systems relied on it. Most of the brokers were always running at 15k to 25k messages per second.
I loved it and the only issues we had were due to our fuckups.
How do you manage schema for exchanges, queues, and routing? The pattern seems to be for each client to set up the schema for the parts they touch before hand, but that doesn't scale well. The schema ends up siloed in each project and nobody knows what the current state should be.
Clients creating server topologies does scale very well with the new Khepri metadata store in RabbitMQ 4.0. Applications having an intimate relationship with their middleware (RabbitMQ) and creating flexible routing topologies is one of main strengths of RabbitMQ!
RabbitMQ also allows operators to import (exchange, queue, and binding) definitions on boot.
Server topologies can nowadays even be declared via YAML files in Kubernetes (https://github.com/rabbitmq/messaging-topology-operator). This way all the desired state is in one single place and the Kubernetes operator reconciles such that this declaratively declared desired schema is created within RabbitMQ.
Probably using it wrong if complaining about AMQP queue scale limits...
Perhaps people are still thinking in single point of ingress design paradigms. Admittedly RabbitMQ can be a pain to administer for Juniors, but then again so are the other options. =3
I know this is said a lot about things people don't like or think doesn't scale but I think I a lot of people don't set it up and use properly and it doesn't scale doing their half-baked implementation.
I could say the same thing about NSQ which is a distributed message queue with very simple semantics and a great HTTP API for message publishing and control actions. What it doesn't offer natively is HA though.
People will be surprised on how far you can get NSQ.
It doesn't come with any fancy guarantee like only-once or even ordered, this forced developer to think how to design better on the application side. Not saying it's ideal tho.
Do you know of any book or video to get started with Rabbit?
Earlier this year I tried setting it up as a websockets message broker in a Spring Boot app but failed miserably. I ended up using Spring’s simple broker.
RabbitMQ can also act as a native MQTT broker. For edge applications/devices, you can also use MQTT over websockets: https://www.rabbitmq.com/docs/web-mqtt
I lost a lot of respect for the RabbitMQ maintainers when they refused to honor the semantic versioning scheme in package managers like nuget/maven/etc. "Safely upgrading" was impossible. 3.5 => 3.6 saw the removal of an argument.
They didn't lose my respect for the removal of the argument, however, they lost my respect for whatabouting the conversation calling SemVer a "no true scotsman" fallacy, then trying to claim that removing a redundant argument is not a breaking change, and other reality-warping nonsense, before blocking myself and other complainants from their issues - and even deleting some of their own comments to mop up some of their own terrible reasoning.
I'm sure there is no love lost on their side, either. Personal rant over.
> I lost a lot of respect for the RabbitMQ maintainers when they refused to honor the semantic versioning scheme in package managers like nuget/maven/etc. "Safely upgrading" was impossible. 3.5 => 3.6 saw the removal of an argument.
Well, at least AMQP 1.0 is now supported so I expect that for most things you are able to use any client now.
When you said that number, I had a completely different reaction. 20 messages per second is absolutely nothing, $0.50 per day for that is dreadful. A $5 per month ($0.16 per day) VPS can deliver many thousands of messages per second.
You TRULY NEED to be multicloud? That would be only reason. Otherwise, assuming SNS/SQS is meeting your needs well, I wouldn't even consider it. You are paying ~20 USD per month with no maintenance costs. That's hell of a deal.
I probably wouldn't swap unless you have a specific complaint with SNS/SQS. I do like how easy it is to spin up Rabbit locally via docker-compose for testing, but I don't think that convenience is worth refactoring a significant portion of your code base.
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Too many people end up with their own half rolled pubsub via things like grpc, and they'd be far better off using this, particularly in the early stages of development.
It's an infinitely more friendly version of Kafka, pub/sub, etc that is extremely lightweight. Yet every environment trends towards Kafka because it was "chosen" by the big corps.
It's nothing to do with these apps being superior in any way - often it is the opposite - like reasonable faults and glitches can add more hours to bill the customers for "fixing".
"Key value", "pub-sub", "microservices can live anywhere" And?
Why do I care? What does "microservices can live anywhere" even mean and what does it have to do with NATS?
I find RabbitMQ sometimes inscrutable but I think even their website is better
The new Khepri metadata store in RabbitMQ 4.0 allows for even better scalability.
Just wondering what the biggest selling points are for somebody making a decision?
We needed features like job priorities, and complex routing logic and on top of that our software needs to send millions of messages a minute. What we miss is a nice UI to see the state of jobs, and monitor for problems more easily like: https://taskforce.sh/
[1]: https://www.rabbitmq.com/tutorials/amqp-concepts
> RabbitMQ is a reliable and mature messaging and streaming broker, which is easy to deploy on cloud environments, on-premises, and on your local machine.
What does that mean? "Messaging and streaming broker"? I understand the need for worker queues to process videos, images, emails and such but I can't easily tell if that's what this is.
Also, what are the benefits of this over just processing incomplete records straight out of my database? i.e. using MySQL as a queue.
Mainly throughput and latency. I haven’t used MySQL recently so some of this may apply more to Postgres.
Postgres has LISTEN/NOTIFY which helps with latency. I don’t think MySQL has LISTEN/NOTIFY, which means you’d have to resort to polling.
You have to use the `SELECT … FOR UPDATE SKIP LOCKED LIMIT 1` features to grab a message from the queue table, so multiple consumers don’t pull the same message.
The biggest issue, if you’re trying to achieve decent throughput, is dealing with bloat (empty pages still sitting on the disk that haven’t been cleaned up yet). You can run vacuum but an online vacuum will only mark the pages as available for reuse (doesn’t free up the disk space). And if you run a full vacuum (which will free the disk space) it locks the entire database while it runs the vacuum. This can compound if you’re using indexes.
One way of dealing with this is setting up partitioning by message timestamp, so that as old messages roll out, you can just drop those partitions and not have to deal with vacuum.
It can work if your queue needs are low throughput or can tolerate higher latency, but there are some things to manage, and realistically setting up a Redis instance is probably less complex than trying to work around the database-specific quirks, unless you’re already very familiar with your database’s inner workings.
Dead Comment
If you are looking at RabbitMQ with "Maybe this is too much". Beanstalkd likely has features you need with almost none of the setup. Just don't web expose it ;)
I only used it on one project years ago and it was a pleasure, dead easy to get up and running and rock solid.
You have to read a lot of docs or you WILL hold RabbitMQ wrong.
The ideal RMQ cluster has 3 servers and is dedicated to just a few apps.
The biggest issue back then was finding a quality client implementation for the language you were using. Not sure what the status of that is these days.
Its unfortunate your team ran into performance issues, as Erlang can be inefficient in some situations. Were you using static routes on the DNS load balanced parallel consumers, or relying on the disk caching mechanisms?
I haven't touched it in years so I can't expand, but when I did, I had to write so many wrappers and add extra logic to use it properly.
Does RabbitMQ have equivalent features?
[0] https://www.rabbitmq.com/stream.html
Reminds me, I'll have to check if they have a working donation link someplace. =3
BEAM languages (including Elixir and Gleam) share the benefits Erlang enjoys by also being part of the ecosystem.
I loved it and the only issues we had were due to our fuckups.
Perhaps people are still thinking in single point of ingress design paradigms. Admittedly RabbitMQ can be a pain to administer for Juniors, but then again so are the other options. =3
I can’t speak to the new version, but it comes with support for even more messaging patterns out of the box.
Earlier this year I tried setting it up as a websockets message broker in a Spring Boot app but failed miserably. I ended up using Spring’s simple broker.
Edit: FWIW, NATS also supports MQTT: https://docs.nats.io/running-a-nats-service/configuration/mq...
They didn't lose my respect for the removal of the argument, however, they lost my respect for whatabouting the conversation calling SemVer a "no true scotsman" fallacy, then trying to claim that removing a redundant argument is not a breaking change, and other reality-warping nonsense, before blocking myself and other complainants from their issues - and even deleting some of their own comments to mop up some of their own terrible reasoning.
I'm sure there is no love lost on their side, either. Personal rant over.
Well, at least AMQP 1.0 is now supported so I expect that for most things you are able to use any client now.