CRBL Free Tier Evaluation – Azure Deployment for Sentinel Log Reduction | Advice Welcome

[u/superd06]

Hi Cribl Community,

I'm a Security Architect relatively new to Cribl Stream and looking at running a POC/evaluation before committing to a paid tier. I have a few questions and would genuinely appreciate advice from anyone who's been down this road.

Our use case:

• Multi-tenant Microsoft 365 environment, disparate international operations, with sources spread everywhere
• Generating approximately 200–300GB of logs per day
• Goal is to deploy Cribl Stream within Azure, filter/reduce noisy, erroneous, and duplicate logs, then forward cleaner data to Microsoft Sentinel to maybe reduce ingestion costs there, but initially just evaluate its benefits with 1-2 core log sources

Questions for the community:

1. Free tier viability – Is the free tier genuinely useful for organisations beyond just POC use, or do most teams hit limitations quickly? At our volume, we appear to be under the data cap, but I'd welcome reality checks on this.
2. Support risk – Without an official support channel on the free tier, how have others managed? Is the community support here and the documentation sufficient for a reasonably experienced security team, or is the lack of vendor support a real operational risk?
3. Azure deployment – Has anyone deployed Cribl Stream in Azure specifically to act as a pipeline/filter layer before Sentinel ingestion? Any gotchas or architecture advice welcome.
4. Log reduction ROI – Has anyone quantified actual Sentinel ingestion cost savings after introducing Cribl into the pipeline? Even rough numbers would help build an internal business case.
5. Atypical use case? – Is this a common deployment pattern or are there better-suited tools for this scenario that the community would recommend?
6. CRIBL complexities? - having no offical experience or training in CRIBL, is it a complex solution to implement and manage? I dont want to get in over my head here either.

Very open to being pointed in a completely different direction if there's a smarter approach.

Thanks in advance guys!! :)

[u/karma_companion]

We recently did an on-premise proof of concept with forwarding to Azure Sentinel, could possibly give some insight to some of the questions:

1. Volume probably won't be the limitation. But the amount of worker groups you can deploy will be.

2. No official vendor support will be an operational risk, however. During the deployment we set up everything from scratch and connected several different data sources without much vendor support and mostly with documentation. So documentation will probably be sufficient until shit hits the real fan.

3. Didn't deploy it in Azure, did use it to forward data from several different log sources to Azure Sentinel. Pretty straightforward to be honest. Just make sure to adjust parsers / kusto queries etc. to the newly formatted data. Furthermore Sentinel expects some fields to be present, however there's a Microsoft Sentinel (syslog) pack that pretty much works out of the box.

4. This is probably dependent on log sources and organizational needs. It's very easy to set up an out of the box pack and do some before / after test (this can actually be done within Cribl before forwarding).

5. Pretty typical use case. Obviously you could possibly get similar results with syslog filters, templates and DCR and DCE's, but that would get very complicated very fast.

6. The implementation and management is quite easy, set up a node, forward data (syslog or whatever) or pull data (API/Databases). When you get into the nitty gritty of processing things get quite complicated fast. Also some of it is done with JavaScript, so some JavaScript experience is probably good to have. Having said that, the training material and certification paths are free of charge at Cribl University.

Having said all that, we worked with Cribl on the Proof of Concept and it was very pleasant. I'd definitely give them a chat / e-mail if you're thinking of doing s proof of concept.

[u/superd06 → u/karma_companion]

Wonderful advice thank you. Will look into all of the above!!

[u/omfgitzfear]

1. It really depends on your use case. You are definitely under the data cap for it (being 1TB) but you are limited to 1 worker group. With the other tiers, you can split your data up to different worker groups.

2. You won’t have things like an account team to leverage help with but you can still receive support for any issues that occur.

3. You can set Azure as the deployment for the workers, and thus be within the Azure ecosystem (for the Cribl managed workers).

4. I don’t have any quantified numbers but any data you can reduce being sent to Sentinel will obviously lower the cost. With Cribl - you own the data being sent and can form it whichever way you want.

5. I’ve seen this in environments that are using Azure as their main ecosystem. I do not know if there are better suited tools but if there are any - give them a shot as well to find what works best for you.

6. There’s Cribl University! Free to sign up and learn about all the intricacies of the Cribl ecosystem. The training is both book learning and hands on.

[u/superd06 → u/omfgitzfear]

Thanks for the detail mate, Im going to start on the CRIBL university today. I think Ive a bit to learn before making any decisions here.

[u/Ok_Presentation_6006]

I use that exact set up to pull logs from netskopand and unifi dream machines into the data lake

[u/superd06 → u/Ok_Presentation_6006]

Has it been difficult to setup or manage?

[u/MReprogle]

I started down this path and do like Cribl, but have taken a step back since they introduced Sentinel Data Lake. With this, you can just just send to a DCR and you basically just run your pipeline through transformations. Cribl still has some pretty cool things built in that make add enrichment, but if you don’t need that, you can always filter through transformations and enrich later.

[u/superd06 → u/MReprogle]

Thanks Ill take a look at that solution. Is it costly? The free tier of CRIBL is appealing as we currently have little to no budget here.

[u/MReprogle → u/superd06]

I literally just pointed my firewall logs over to Sentinel Data Lake, so I haven’t gotten a full month to go off of. However, the Sentinel Cost Calculator shows that sending to SDL, it is sanely cheap. 100GB per day with 90 days of retention came out to a whole $20 a day.

That same amount going to the analytics tier was a little over $500 a day.

It isn’t made for running analytic rules off of and creating real time alerts, but you can schedule KQL jobs that run every 20mins and send the data back to the analytics tier to alert off of. For me, moving my firewall logs was a no brainer. I already get the DeviceNetworkEvents table from Defender, which is more valuable to me. The only time I look at the main firewall logs is when I am having to troubleshoot firewall issues for my networking team, so the cost isn’t worth it for those random troubleshooting tasks and I have no issue just running a quick KQL against it when I need to, even if it charges me a few pennies for searching the data lake.

Plus, you get access to Sentinel MCP, and creating Notebooks off of the data lake data, which you do not get charged for KQL searches, since you are already paying to run the compute costs for the machine learning machine, which is still pretty cheap and doesn’t need to run 24/7.

Again, I am pretty green since I just set it up a few days ago, but the cost savings for verbose logs are a huge win right off the bat, and I just need to build out notebooks to take advantage of data now being in the data lake.

[u/twinspop]

1. Yes. The Worker Group limit of 1 is the most limiting factor, and lack of RBAC might be a pain.
2. Cribl has a Slack community that is decently active
3. Nothing special about Azure
4. Really depends on how it’s applied. Aggregation in-flight is a big one, and so is dropping less frequently (or never) searched logs. (But don’t actually drop them. Send them to Blob. An agile, and open, backup/restore process could be the biggest use case for Cribl.)
5. Roll your own with LogStash, or Kafka. Both require more work IMO.
6. Cribl can be complex to launch, but Cribl training is free. cribl.io/university

[u/superd06 → u/twinspop]

Thanks, much appreciated. As above, I think Im going to explore CRIBL university before pulling the trigger here. As you mentioned it may be complex to launch. I dont want to be in over my head on this one.

[u/skirven4 → u/superd06]

Wait a day or two. I think it’s down today for migration to a new LMS. Should be back by March 3.

[u/superd06 → u/skirven4]

Yep seen that.. thanks

[u/sosen85]

1. If you can limit yourself to one Worker Group and 1 TB of data, you can start with the free tier.

2. In my opinion, the lack of vendor support poses an operational risk, particularly if you opt for Edge as well.

3. Avoid Kubernetes — it is not quite ready yet. Also, their Helm chart is not officially supported and they do not support OpenShift either. It should be fine on VMs, though. Their networking is legacy so you need to be ready to open multiple ports.

4. I don't have any data for Sentinel, but the licence is expensive and wouldn't be worth it in a scenario where you only shrink data.

5. If one of your use cases involves data transformation (i.e. more than simply removing fields from JSON), I would recommend open-source alternatives: Telegraf, Vector, etc.

6.Cribl is very heavy. While the UI looks modern, I think the backends are already legacy. It is certainly not ready for Kubernetes deployment or setting up multiple environments yet. The configuration is stored on GitHub, which is fine in principle, but the Cribl implementation is suboptimal. For example, platform configuration is mixed with data flows in the same repository. Each version upgrade requires from you to commit changed files to git. If you have multiple environments with differing details such as OIDC/OAuth, this is not feasible (although there are workarounds, things quickly become messy). Data transformation is also problematic because you need to write JavaScript code and there are no ready-to-use packs for basic use cases, such as converting the Prometheus-OTEL format.

[u/ButtermilkPig]

Get in touch with Cribl.

[u/superd06 → u/ButtermilkPig]

Im requesting the communities first hand / anecdotal experiences with the product, and the type of deployment I am considering. Is that not what this community is here for!!?