2025-09-03
When building, and especially testing, Vortex, we use several cloud VMs with different kernel versions (usually LTS ones), and a dedicated GKE test cluster. The trouble with eBPF though, is that a lot of the features depend on what kernel version is running on the target system. And maintaining multiple cloud VMs with different kernel versions is a tad expensive, and really not that straightforward. And so, QEMU to the rescue. When it comes to emulators, QEMU doesn’t really need introductions. This blog is a guide (mostly to myself) on how to build a Debian-based image with a specific kernel version to be used as an eBPF testbed.
Startup · Startup · Updates · Updates
3 minutes
2025-08-21
A quick update on what I’ve been building for the last couple of weeks. I’ve put together a small team at Alphaus to explore eBPF with a specific goal: building a tool for AI security and monitoring. The kernel-level visibility you get with eBPF is perfect for this, but the real work is in making it useful. Our immediate focus has been on getting visibility into encrypted network traffic. We needed a way to inspect TLS traffic without messing with certificates or acting as a man-in-the-middle. The obvious path was using eBPF uprobes to hook user-space functions directly.
Startup · Startup · Updates · Updates
2 minutes
2024-05-13
I posted a blog introducing the DIVS model, the process we use at Alphaus, the startup I work for. Check it out here.
Agile · Development · Process · Startup · Tech
1 minute
CTO Diaries #3: On choosing technology stacks
2023-04-01
When it comes to tech stack selection, in general, I always approach it in terms of tradeoffs. And when it comes to understanding tradeoffs; what you gain vs what you lose, I think experience plays a big part. In my 18+ years of experience building systems, I’ve been bitten enough times that I view most of them with a fair bit of cynicism. I wouldn’t really say that experience definitely makes me better at it; I still have my own biases and experience doesn’t really ‘fix’ the illogical side of me being a human being with emotions. It gets in the way at times. Then there’s the business side of it as well. An example would be to maintain business relations, or to honor partnership agreements, I would need to use (or integrate into) some tech stacks that I wouldn’t normally choose in the first place. And to add to all of these, I also work in a startup with limited resources so there are other criteria that have a bigger influence on my approach to balancing tradeoffs. And at our phase right now, probably the biggest one is cost. Not just monetary but engineering costs as well: cost of operating and managing these systems. And I must admit that cost considerations is at times so pervasive to me that I would choose a technology purely because I got a significant discount for it even though at the back of my head, I know it’s going to come back to me later on. So much for experience, huh.
Cto · Cto-Diaries · Diaries · Startup · Tech
5 minutes
2022-09-27
Hi. It’s been a year since my last「CTO diaries」post. Never mind the excuses, there’s a lot. Anyway, so what does my typical, or normal day, look like? Well, I usually start the day with checking the overall health of our systems. We don’t really have very sophisticated monitoring and alerting systems at this point so this means checking on several areas such as our Kubernetes clusters, databases, and critical services. On top of my head, I think the most common service crashes I noticed so far are OOM-related.
Cto · Cto-Diaries · Diaries · Startup
3 minutes
2021-09-28
So far, I’ve been posting some techy stuff here and there but being a CTO of a relatively small, Japan-based startup for about three years now, I thought I’d share some of my experiences along the way. But first off, a little bit of context: the company I work for, Alphaus Cloud is fairly small; about 10 engineers scattered across three countries, although at one point, we hit at around 35. It started around 2015, did three product pivots, three rounds of funding under two CEOs. At the moment, we operate within the Cloud FinOps (financial operations) segment of the market. As for myself, I am what you would consider an ‘accidental CTO’, a term I came across from CTO Academy, and a term I quite like: i.e. “someone who arrived in the CTO role ahead of schedule and is grappling with new challenges and very steep learning curve”. You can call it luck, although that would be relative, depending on one’s interpretation. Also, Japanese is not my native tongue, although I think I can hold my own in day-to-day conversations, nor is English, but I think I’m fairly proficient at it. And even though the company is trying to expand its operations outside of Japan, it is still inherently Japanese as far as business operations are concerned: the CEO/COO, sales, customer success teams are Japanese, investors are Japanese, and majority of our clients are also Japanese companies.
Cto · Cto-Diaries · Diaries · Startup
3 minutes