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Comment by agallego | Hacker News Reader

I'm Alex, the founder. Happy to answer any questions.

Hey Alex, Alejandro here :wave:

I was a bit surprised to see the announcement about making Redpanda open source (although very interesting for poking around!).

Question: are you, as a company (Vectorized) pursuing the same business model as the Confluent one? OSS Kafka, but paid official support, cloud, connectors and registry?

We had success with very large customers (enterprise) and also some success with finance company (looking for 0 data loss). The idea is that we can give the kafka API compat system with 10x lower tail latencies for free and still monetize the high end of the market.

I think there is a big shift when you have a single binary. i.e.: no one really complains from running ngix, etc because it's easy to get up and running.

so the gist we wanted to let everyone use it and reserve the right to be the only hosted redpanda provider.

also i'd note one more thing which is the WASM API is going to give us an opportunity to add more enterprise value.

i.e.: think GDPR compliance as long as your data streams are in JSON or some predefined format.

WASM basically allows us to push computational guarantees to the storage engine itself without a separate cluster.

what does WASM mean in this context?

https://webassembly.org/

Thanks -- I had never considered using webassembly in this way, so I thought it was something different.

Is there a blog post or docs showing using WASM? I searched your site but couldn't find details.

I've failed to grasp if it's an "alternative plugin-engine" kind of system to extend Redpanda, or you're storing data as WASM and therefore it's executable (to take your example: GDPR compliant auto-expire if it's past a certain date).

> so the gist we wanted to let everyone use it and reserve the right to be the only hosted redpanda provider.

It seems totally fair to me. Good luck with this approach. I think yours odds are good.

If I am reading the fields of this implementation of BSL correctly, it will be open-source software in 10 years, when it converts to Apache 2.0, but not today. Until then, the license does not comply with the open source definition due to field of use restrictions.

" Our intention is to deter cloud providers from offering our work as a service. For 99.999% of you, restrictions will not apply - welcome to our community!"

"For 99.999% of you, restrictions will not apply"

This is simply not true. The restriction applies to 100% of everyone using the software under the license.

If an alternative service provider can't legally host the service for me, I am restricted from selecting an alternative vendor if my needs converge from the available vendors offerings.

Further, it still isn't open source.

Yes, all of us are bound by the terms alike but I think everyone understands it was meant as commercial and non-commercial use for 99.999% of you will not trigger the respective clauses in the license. And the post title literally says "Redpanda is now Free & Source Available".

But there was at least one ancestor comment that said it was open source, and that is what I was replying to.

It is not open-source, it is source-available. That's a perfectly valid choice, but the two approaches shouldn't be conflated.

I am guessing the difference is that

1. You can't just take this and make money from it

2. They don't accept or expect external inputs.

Hi there. Of course you can make money using it. The main restriction is to not run redpanda as a service. Otherwise have fun.

Its the same as cockroachdb in that regard

How can you run redpanda any other way? :)

feel free to embed, ingest customer data, run on a saas application. The only restriction is hosting redpanda as as service for other customers (Think AWS MKS)

If you have any questions or think your use may be confusing please reach out to us.

Hi Alex, I'm an amateur programming language enthusiast & designer, so I've a question related to this.

Looks like the project is mostly written in C++ and Go. What was the reason for this choice? Have you considered other languages, like Rust, Zig or similar instead of C++? TBH not sure what an alternative to Go would be, maybe JVM AOT-compiled with NativeImage (but AFAIK that's still experimental).

Did Go's GC and/or C++'s lack of GC help/impede the project? IMO memory management is one of the main differences between languages... the other is concurrency / memory model / undefined behavior, where JVM is significantly ahead of the rest (no undefined behavior), I'm not sure exactly where Go stands (there seems to be a memory model, but no mention of undefined behavior or lack thereof).

Hi there!

Sure thing. I basically was playing with an RPC framework to make my old company project fast in 2017 see github.com/smfrpc/smf

I wanted to play with dpdk then.

When I started this in 2019 I wanted to use a framework that was battle tested, so seastar.io fit the bill.

There is also a big part of it that I had been professionally programming in c++ for many many years.

Last, this evolved from a prototype on my laptop in miami to company.

I think rust would he am excellent choice as well and I bet we'll write a bunch of rust in the not too distant future.

Hi Alex - This looks a lot like what Scylladb did to unleash the potential of the Cassandra space, with a fully optimized C++ rewrite of an Apache project. Did you draw some inspiration from their efforts?

As a satisfied Scylla convert, I'm looking forward to trying Redpanda.

hi there! scylla is great :) we are built on the same framework seastar.io so we literally share code bases in that regard.

Main departure is we are only API compatible. It was an explicit choice to use Raft vs ISR and to not use ZK, etc.

but indeed, seastar is a really fun framework to build storage systems in. I know ceph is also doing a re-write of a subsystem in seastar for example.

I'm a fan of scylla too, but if I could go back in time I'd have recommended waiting until mid 2019 to migrate. 'Fully optimized C++ rewrite's tend to take years to become battle tested.

In fact, we couldn't switch to Scylla prior to 2019 because their support of incremental counters wasn't yet complete.

totally. today if folks. need txns, they wouldn't be a good fit for us. What we found is about 90% of use cases are covered by the base api. For reference w/ all of the versioning there is something like 144 api calls you can make to kafka, most ppl use a small subset of those via high level clients. (java, python, librdkafka, etc)

indeed. that's why we continuously _empirically_ prove that we are in fact safe - https://vectorized.io/validating-consistency/

there is no substitute to testing tho

there are 2 levels here. 1) raft has a proof (and a great phd dissertation from diego), but what matters is if we actually implemented it correctly. so 2) is we need to continuously test it. Denis did a lot of similar work at CosmosDB (microsoft) and has spent his career working on consensus.

Hopefully these eases some concerns.

Hi, I need to decide in the near future on a scalable messaging solution with at-least-once or better guarantees for our own SaaS platform. I'm looking for something that can be deployed on-prem, that's not targeted only for the public cloud. Do you have any documentation on how best to deploy redpanda with Docker and/or Ansible? What are the best practices on rolling out the cluster in-house? I've seen some docs on tuning that referred to AWS types of instances, is there something that you could refer me to that is more generic and not tied to a specific cloud vendor?

I'm asking partly because we must be able to offer closed on-prem installations as well as SaaS on a cloud. I'm looking for a low-ops component that will not fail me (as often as alternatives would) :)

we are happy to help and answer any questions. Join our community slack channel or hit the contact us button on vectorized.io

Hey, congrats on publishing your source. It's a very interesting project indeed. I took a look around and I think with a bit expanded documentation, especially examples using the WASM transformations and maybe a some emphasis on durability and other guarantees it could grow into a great project.

I'd be interested in the write amplification since you went pretty low level in your IO layer. How do you guarantee atomic writes when virtually no disk provides guarantees other than on a page level which could result in destroying already written data if a write to the same page fails - at least in theory - and so one has to resort to writing data multiple times.

Hey, looks really interesting. Would love to see benchmarks that are open source so we all can check it out in more detail.

Seems like a lot of questions on here are just: how much better is the performance and why?, so maybe showing is better than telling.

Best of luck!

hi tim. absolutely, we exect ppl to test. public benchmarks coming in December. We'll probably just pick the open messaging benchmark that has been going around pulsar+kafka communities so folks can have a frame of reference.

Though what is to me more interesting, is what happens when you inject failures while the benchmarks are running.

What's end-to-end latency for a local cluster like? What's your business model?

I'm a big fan of kafka as an abstract building block, but not so much the actual implementation, which is as painful to setup as a consultancy-based business model might make you suspect it would be, especially if you need reliability. The other problem is that performance kind of sucks, apart from potential latency spikes due to GC pauses I found even the average latencies for reliable end to end (in a fast local network and on decent sized hardware) not in right order of magnitude ballpark.

Regarding biz model.

-Redpanda (free) - comparable features to Kafka, no limits -Redpanda Enterprise (paid) - Additional features (security, WASM, tiered storage, support etc) -Vectorized cloud (Free and paid tiers) - Hosted in AWS+ GCP

Hey Alex, this looks very interesting! From browsing the docs it appears rpk tries to mess with cgroups and some kernel settings... is there compatibility mode for running unprivileged in a container environment such as kubernetes? Thanks!

The tuning isn't 100% necessary, it's there primarily for running max performance on metal, and you can pick and choose what to tune.

In general it probably best to run with:

--smp <n> --overprovisioned

for a container with <n> CPUs.

These are standard Seastar flags.

basically what ben said.

we also have a container image `vectorized/redpanda:latest`

It sounds like Vectorized is a streaming platform built on top of Redpanda. Is that the right way to think about it? If yes, then why not build it directly on top of Kafka instead?

We kind of started on a different note. We wanted to solve some fundamental problems (no Zookeeper - similar to KIP-500) and most of all we wanted a single binary we can ship around, something that is easy to run.

I think people LOVE the kafka _api_ but they have a hard time operating clusters at scale. So we decided to keep the same API but solve the problem of operational complexity.

> I think people LOVE the kafka _api_ but they have a hard time operating clusters at scale.

That is very true, and this is what you should emphasise. Wish you the best of luck!

The actual speed of Kafka has rarely been a concern (but huge numbers of partitions are, which makes rebalancing a pain) in my experience, in fact it was mostly overkill. But operational complexity was definitely an issue!

Will do. Thank you. Do you have any thoughts here. How would you say it differently. We tried that on the landing page

Landing page isn't bad, when you scroll the important points are there, but you have scroll. I'm not a "landing page optimisation guru", so take this with a grain of salt, but I would change it as follows.

Without scrolling, all the text thats displayed is this:

"Redpanda

A Kafka® API compatible streaming platform for mission-critical workloads.

Try Redpanda today"

It tells me what it is, which is good. It does not tell me why it is better, for that I have to scroll. Kafka is already suited for mission-critical workloads, so that is not a unique value proposition. Maybe:

"Redpanda - 100% Kafka API compatible, but without the headaches. Forget Zookeeper, forget rebalancing issues. Instead, enjoy reliable message delivery, 10x faster speed and ultra-low latencies due to our thread-per-core architecture."

Something like that, plus a visible "call to action" button, maybe "try it out" or "download".

Could also think about a pretty graph comparing latencies or smth. People love pretty graphs.

Sweet thanks! passing this to the designer.

@MrBuddyCasino - I tried incorporating the design on the site we launched 5 seconds ago. lmk what you think (alex @ vectorized.io ) is my email in case you feel inclined :D thank you tho.

Hi Alex, i don't see any client document. Can i use kafka java client with it?

This should work fine. If you have any issues, please report as a bug.

What do you mean with "Resilient to Scan-The-World"?

I'm not Alex, but I would assume he means scanning cold data will not evict all the hot data from the cache. This is a common problem with cache eviction algorithms.

indeed.

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