Keyboard meet head

On dishwashers and Nix

Mon, 05 May 2025 00:00:00 +0000

I have many unfinished blogposts about Nix. It is a very broad topic and it's hard not to get lost half-way through writing it. So I decided to try something different. Get a bit more personal and try to write about one of my weird obsessions and about a piece of technology that I learned to appreciate.

One is dishwasher and the other is Nix. And you'll be the judge which one is which. There surely is some kitchen sink joke in there, but let's just dive right in.

Look ma, no Hass!

Mon, 27 May 2024 00:00:00 +0000

I've been tinkering with ESPHome</a> recently, trying to add some air quality sensors to my household. There's a lot of good tutorials out there, but they almost universally have one thing in common: they assume that the end goal is Home Assistant integration.

Which is cool piece of software, but I don't have any use for it right now. All I want is to monitor few air quality parameters, send the metrics to metrics DB and render nice graphs in Grafana which I already have for monitoring other stuff.

My favorite log aggregation service

Mon, 20 May 2024 00:00:00 +0000

Previously, I wrote about my favorite home lab metrics DB</a>. This time I wan to talk about another component of monitoring stack - about log aggregation.

Spoiler: this post is going to be about Grafana Loki</a> and how the promise of cost effectiveness and ease of operation works really well in the unique environment of home lab and small self-hosted networks.

Sudo just a bit

Tue, 19 Mar 2024 00:00:00 +0000

The man page</a> says that sudo allows a permitted user to execute a command as the superuser or another user, as specified by the security policy. However most of the sudo use that I've seen/done is really a privilege escalation with switched user being just a consequence of that. Even the famous XKCD 🥪</a> webcomic shows sudo being used in this way. Most of the time this small difference does not really matter, but sometimes it's really inconvenient.

This is mostly a note I've written for my self so that I can quickly recall how to sudo</code> when I really only want to do</code> something without the su</code> part</a>. Let's have a look at another less popular but sometimes quite a bit more appropriate option.

Migration to cold storage with Rustic Sat, 02 Mar 2024 00:00:00 +0000 In the previous article</a> I've looked at economic side of using cold storage for Rustic</a> backups. In this part I'll look at technical side of things - setting up the cold storage, migrating existing repository to this backend and restoring from backup. Economics of cold storage with Rustic Fri, 01 Mar 2024 00:00:00 +0000 There's alternative implementation of Restic</a> rewritten from scratch in Rust - Rustic</a>. It offers some extra neat features. One such feature is support for cold storage. This blogpost started as my research notes to figure out whether it makes financial and technical sense to use this. I've ended up writing two articles in the series. This part focuses on economic (both financial and complexity) cost of such solution. NixOS on Contabo Mon, 26 Feb 2024 00:00:00 +0000 Contabo</a> is an EU-based VPS provider with reasonably affordable pricing. However, it does come with some compromises. The billing structure is monthly with a setup fee, making it more suitable for specific workloads. Another limitation is the limited official OS support, specifically the absence of NixOS as an option. Online resources on setting up NixOS on Contabo are scarce and can be clunky or outdated. Here's my approach that's hopefully easy to follow. Lenovo P500 remote management via serial port Thu, 13 Apr 2023 00:00:00 +0000 Outside of very specific deployments and industries, serial port on a modern hardware - if present - is usually overlooked and completely ignored. Over the years it became the floppy of external ports. These days one is more likely to see it as an icon representing I/O port than to physically use it. Which is exactly why I also didn't see it for what it was - a simple, yet elegant solution to my particular problem. Because as it turns out, serial port still has much to offer even in 2023. HTTP 500 - Very internal server error Tue, 04 Apr 2023 00:00:00 +0000 As far as downtimes go, most suck. Then there are some that are more like happy little opportunities to learn something new. When Gitlab in my homelab started returning 500</code>s, I had no idea how blessed I was. I was at best annoyed. My favorite home lab metrics service Thu, 26 Jan 2023 00:00:00 +0000 Looking at my git history, I've been happily running InfluxDB for years. However nearing the end of 2021, after long time of peaceful coexistence among my monitoring services, some more or less pressing problems emerged: The long-term future of InfluxDB 1.x</code> is uncertain, it's pretty clear that I'll have to migrate to 2.x</code> in foreseeable future.</li> Memory usage becomes a bit problematic. Well, that's quite an understatement. The container ran out of memory frequently and I had to bump up the limit couple times already. Despite that, I can't even graph longer time spans without getting InfluxDB OOM killed and it's at this stage by far the most memory intensive service I ran. There are presumably some improvements in InfluxDB 2.x</code> that could help here.</li> </ul> The solution seems pretty obvious, however in the end this post isn't really about InfluxDB. LXC and the mystery of lost memory Mon, 21 Feb 2022 00:00:00 +0000 In my homelab I use LXD/LXC quite a bit. Linux containers provide pretty decent alternative to full blown virtualization with smaller overhead and some extra perks like easier local filesystem access. All things considered, I’ve been happy with LXD for many years. However there are places where the illusion of completely separated virtual machines shows some cracks when you look close enough. This is a story of one such crack that was haunting me for months. Docker in WSL2 (the right way ++) Fri, 18 Feb 2022 00:00:00 +0000 This is an extension of very helpful article Running Docker on WSL2 without Docker Desktop (the right way)</a> by Felipe Santos. My post attempts to go further and solve a very specific issue within WSL - the absence of nftables support. This is something you might not encounter unless you start running docker in docker or attempt to run docker images that rely on nftables support in some way. I tend to use Molecule</a> quite heavily and I often end up using docker to emulate actual full blown linux systems or kubernetes cluster in a container, which is where the absence of some kernel features shows up. VFIO GPU pass-through on Dell R710 Thu, 05 Mar 2020 00:00:00 +0000 There’s a plenty of articles out there on VFIO GPU pass through out there, so I’ll skip many of those details here to let us focus on stuff that’s somewhat specific to Dell R711. Before we get to the nitty gritty details of the whole setup, just a short warning: If the GPU pass through is the only use case you want to cover, starting with Dell R710 is absolutely not the way to do it. Here’s why: Pipeline notifications from Gitlab to Matrix via Webhook Proxy Mon, 11 Mar 2019 00:00:00 +0000 Currently there's no official out-of-the-box integration available in Gitlab that would allow you to post messages via Matrix protocol. There are some 3rd party options available, like Gitlab plugin for Maubot</a>, or the Slack-compatible Webhooks Matrix appservice</a>, but it might not be ideal solution in some cases for one reason or another. Gitlab-CI include: from private repository Wed, 24 Oct 2018 00:00:00 +0000 Note: The native support for including files from other non-public repositories</a> was added in Gitlab 11.7, so this workaround is no longer needed. Gitlab added</a> new include</code> statement for the CE edition of their product with the 11.4.0 release, which is great news. However there's this one minor thing mentioned in the documentation: Note: The remote file must be publicly accessible through a simple GET request, as we don't support authentication schemas in the remote URL. </blockquote> This makes it a little bit tricky to use the functionality if you want to fetch the file from private repository. Here's how I got it working. (TL/DR at the end) I've tested virtual address providers, so you don't have to Fri, 27 Jul 2018 00:00:00 +0000 Introduction🔗</a> </h1> The sad fact about online shopping in Ireland is, that many sellers will ship to UK only. It often makes very little sense as they'll happily ship the parcel across Europe to northern Ireland just fine, but that's the status for now. Personally, I'm trying to avoid such sellers to sort of vote with my wallet, but sometimes UK-only seller is the only option or the price difference is just way too big. Fortunately we now have couple services available that can give us "virtual" address in UK and then forward any received packages to Ireland. I've been trying them out over the years and here's some comparison of Parcel Motel</a>, Parcel Wizard</a> and AddressPal</a>. Running Kubernetes cluster with docker-compose for fun (and profit) Mon, 27 Nov 2017 00:00:00 +0000 This could've been called "Learning Kubernetes the hard way", because that's basically what I was trying to achieve here. It wasn't so much about learning how to use Kubernetes via its ingenious API as it was about learning about its individual components. If you want to just run Kubernetes locally, there's Minikube</a>, that will give you nice VM with everything already set up. What I've wanted to achieve is to have a set of components, all nicely isolated with a well defined connection between each other so I can add them, remove them and break the connections and see how this affects the cluster. To put it simply I was interested in Ops side of running Kubernetes. This is why I took Hyperkube</a> and mixed it with docker-compose and tried to stand up Kubernetes "from scratch". Let's get started.. [Part 4] NAScrate files and final thoughts Sat, 14 Oct 2017 00:00:00 +0000 So our build is now done. I'm still thinking about making some improvements, like a proper ports panel or some air circulation control, but it's already very usable NAS box. The only missing part is installing something like freeNAS</a> or some other user friendly NAS OS, but there's a ton of howtos out there, so I'm not going to create another one. Feel like building your own NAScrate? Here are all the files you'll need. [Part 3] Building NAScrate Mon, 04 Sep 2017 00:00:00 +0000 Finally there🔗</a> </h1> I pinky swear it doesn't take 4 months to build the NAScrate. I actually had it done and dusted in couple weeks - most spent waiting for the components with couple evenings spent with Onshape trying to figure out how to fit everything in a small crate. I just didn't have enough time to properly document it, hence the delay in updates. This last step only took couple hours at most - and that's including re-designing and re-printing some of the parts. Building next one with all the parts ready is 30 minute job easily. So let's give it a go. [Part 2] NAScrate design Tue, 13 Jun 2017 00:00:00 +0000 Prototyping🔗</a> </h1> Is this even feasible? There's one way to find out! Well.. there's probably more than one way, but here's what I did. First thing I tried was to model and print rough miniature models of all the components I need to fit inside the case. (which I've printed as well) This gave me general idea, how to put the components in, but it's not accurate enough to see if we have enough free space around the components to actually fit in mounting brackets and all that other stuff. As we'll see later on, in reality there's just few millimeters gap between the components, so anything in the 1:10 scale just isn't going to be accurate enough. [Part 1] NAScrate - the budget for the budget NAS Wed, 10 May 2017 00:00:00 +0000 The idea🔗</a> </h1> The idea is simple really: Build a NAS out of readily available PC components inside Knagglig</a> crate sold by IKEA. As for "why?" - it's the usual answer - to see if it can be done in a practical way. The other part of that motivation was, that I can now print</a> parts of the construction, so it was a good training for my design and construction skills, that are, honestly, quite lacking. Why would you want 3D printer? Mon, 13 Feb 2017 00:00:00 +0000 Why?🔗</a> </h1> I only have 3D printer for about a month and people asked me that question multiple times already.. It's the question every early adopter gets. (is it really that "early"?) Back in the old days of feature phones, people were wondering why I got Symbian phone that was quite a bit more expensive than regular Nokia brick. That was years before iPhones were a thing, so the answer wasn't as obvious to non-techie people out there as it might be today. (and remember, when it was released, even iPhone wasn't all that smart, no app store, no multitasking, no Bluetooth even) Back then the simple (and real) answer was: "Because it's cool!" --- Me </blockquote> And that's really the reason why I got my 3D printer. However I feel like the real answer is different. I no longer feel that the 3D printers are cool for the same reason the pseudo-smart mobile phones with proprietary OS were cool. And to explain that feeling, I have to go few years back. Ansible continuously integrated with Drone Fri, 07 Oct 2016 00:00:00 +0000 Last time when we got our little Ansible</a> setup to spin up Docker containers as systemd services</a>, I suggested that we should perhaps have Drone</a> running the syntax checks and playbook runs for us. Let's give it a try now, shall we? Docker containers with Systemd and Ansible Wed, 05 Oct 2016 00:00:00 +0000 Earlier on I've shown you how I run docker containers on NAS using systemd</a>. This time, I'll show you an easy way to configure systemd with Ansible</a> that will get you running containers in no time. (and in reproducible and automated way) Continuous integration at home with Drone Fri, 16 Sep 2016 00:00:00 +0000 Has science gone too far? It might look so, because: It feels like a huge over-engineering to implement CI at home.</li> What would you integrate anyway?</li> Just why?</li> </ol> Well let me explain my reasons. Automatic SD card backup with USBmount Thu, 09 Jun 2016 00:00:00 +0000 As I've mentioned before, I'm using HP Microserver Gen8 as a small home NAS</a>. There is a lot of stuff stored there, but the primary reason why I actually started using NAS (back then slow, but hackable</a> D-link DNS-323) was to store my photo collection. With ZFS, mirrored drives and extra backup to off-site location, the data on it should be reasonably safe, right? However that's not all that useful if most of the recent photos reside on the SD card inside the camera on in the case somewhere, just because I didn't have time to copy them to the NAS yet. So what can we do about it if we have 15 minutes to spare? Let's automate it a bit! Rebuilding NAS with ZFS & Docker Wed, 01 Jun 2016 00:00:00 +0000 It all started with tripped breaker. In fact it tripped multiple times before I got home. Luckilly the spinning rust drives with data survived that without any issues, but the flash drive didn't. So with system FUBAR and some (little) time on my hands, there's only one thing to do - upgrade. Pushing the check states from Xymon to Graphite Fri, 27 May 2016 00:00:00 +0000 Motivation🔗</a> </h1> Chances are, you never heard about Xymon</a> (formely Hobbit), so let me give you some idea. It's actually pretty decent monitoring system - if you still live in 90s. :D But hey, let's give credit where it's due, compared to other systems at that time, it was reasonably fast, has quite easy to understand configuration, comes with many standard checks out of the box and comes with a web interface. Probably that's why some people still use it to this day. In our company it's one of those legacy systems, that we need to replace, so as a first step, let's see if we can get some of the data out while we're still using it. The monkey remote desktop experiment Sat, 14 May 2016 00:00:00 +0000 The waste of being present🔗</a> </h1> From time to time I work from home - nothing unusual here, I'm actually surprised that this practice isn't more common. After all - unless you're working manually, chances are you are working remotely anyway. Your email, instant messaging - you might be reading them locally on your computer, but they are all stored, transferred and received by server somewhere in datacentre. All your applications are moving to your browser, all your files are moving to cloud. The point is this: A lot of people are working remotely even while sitting at their office chair. Whole companies are like that. Yet, every morning, there are traffic jams and the public transport is overloaded.. And it seems like a huge waste to move all these people around, just to have them working somewhere virtual anyway. Free SSL with static website on S3 Wed, 11 May 2016 00:00:00 +0000 So there's this nice thing called Let's Encrypt</a>, I'm sure you're already aware. If you want to get free certificate for your website in an automated way, it's definitely great. However in my case I would have to make sure to renew the certificate before it expires, which would defy the whole point of using static website on S3 - that is, unless I want to change something, I don't have to touch it. I could perhaps set up a daemon somewhere that would take care of it, but then again I would have to make sure that the service actually runs. Fortunately, there is a way to get the same results with just AWS services. What I've learned from my son Tue, 03 May 2016 00:00:00 +0000 There's one thing that fascinates me about kids. I actually only noticed it recently while watching my little son. The thing is, kids do everything 100%. There's no multitasking, whatever they do, they only do that thing and they are completely focused on it. My son doesn't even speak and probably only understands very few words, yet nobody else will listen to whatever you say like he does. Obviously that's only true when he is listening, when he's not, he's not listening at all. There's no pretending. You either have his undivided attention or you have none of it. Small box, small problems Thu, 28 Apr 2016 00:00:00 +0000 Introduction🔗</a> </h1> Weeks passed and Eggsnows' Celeron J1900 based fan-less PC</a> on my desk was replaced by this little box called MSI Cubi. I've bought the Intel Pentium 3805U based model - there is one model even cheaper than this one with Celeron inside and there are i3 and i5 based variants as well if you need some extra power. I went with the bare-bone version, though if you don't feel like getting the other components (you'll need RAM and some mSATA storage) there are also models with the necessary components already installed. Using Docker with ZFS storage driver Fri, 04 Mar 2016 00:00:00 +0000 Introduction🔗</a> </h1> So I've ended with this ZFS and Docker combination on my home storage some time ago. I use ZFS on Linux</a> to safely store data and I use Docker</a> to run services like samba, plex, owncloud, and others on top of that data. I've been using devicemapper on top of ZFS and it was mostly good. Every now and then I had this strange issue of layer not being available while starting container, (as if docker tried to spin up the container before having the storage ready for it) just re-running the container solved the issue. I've never seen this at work, where we use Docker in production quite a lot and in my case it was transparently handled by upstart so I've just assumed the combination of devicemapper and ZFS caused these. Besides that I was quite happy with the whole system. Recently I was wondering if there was some progress on the ZFS storage backend</a> and I was pleasantly surpriset, that this is actually built in sice couple versions ago. (how did I miss that, I have no idea) So let's try it? Four cores, no fan Fri, 12 Feb 2016 00:00:00 +0000 Introduction🔗</a> </h1> So I've recently bought this Eggsnow Fanless Mini PC</a> to be used as a silent, but powerful enough desktop. Most of the work I do on it is done remotely, so what I really need is something capable running browser, couple terminals and perhaps able to play a movie every now and then.