161 lines
8.0 KiB
Markdown
161 lines
8.0 KiB
Markdown
---
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title: Kubernetes Pondering
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date: 2020-12-31
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tags:
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- k8s
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- kubernetes
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- soyoustart
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- kimsufi
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- digitalocean
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- vultr
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---
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# Kubernetes Pondering
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Right now I am using a freight train to mail a letter when it comes to hosting
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my web applications. If you are reading this post on the day it comes out, then
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you are connected to one of a few replicas of my site code running across at
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least 3 machines in my Kubernetes cluster. This certainly _works_, however it is
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not very ergonomic and ends up being quite expensive.
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I think I made a mistake when I decided to put my cards into Kubernetes for my
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personal setup. It made sense at the time (I was trying to learn Kubernetes and
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I am cursed into learning by doing), however I don't think it is really the best
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choice available for my needs. I am not a large company. I am a single person
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making things that are really targeted for myself. I would like to replace this
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setup with something more at my scale. Here are a few options I have been
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exploring combined with their pros and cons.
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Here are the services I currently host on my Kubernetes cluster:
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- [this site](/)
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- [my git server](https://tulpa.dev)
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- [hlang](https://h.christine.website)
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- A few personal services that I've been meaning to consolidate
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- The [olin demo](https://olin.within.website/)
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- The venerable [printer facts server](https://printerfacts.cetacean.club)
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- A few static websites
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- An IRC server (`irc.within.website`)
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My goal in evaluating other options is to reduce cost and complexity. Kubernetes
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is a very complicated system and requires a lot of hand-holding and rejiggering
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to make it do what you want. NixOS, on the other hand, is a lot simpler overall
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and I would like to use it for running my services where I can.
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Cost is a huge factor in this. My Kubernetes setup is a money pit. I want to
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prioritize cost reduction as much as possible.
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## Option 1: Do Nothing
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I could do nothing about this and eat the complexity as a cost of having this
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website and those other services online. However over the year or so I've been
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using Kubernetes I've had to do a lot of hacking at it to get it to do what I
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want.
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I set up the cluster using Terraform and Helm 2. Helm 3 is the current
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(backwards-incompatible) release, and all of the things that are managed by Helm
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2 have resisted being upgraded to Helm 3.
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I'm going to say something slightly controversial here, but YAML is a HORRIBLE
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format for configuration. I can't trust myself to write unambiguous YAML. I have
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to reference the spec constantly to make sure I don't have an accidental
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Norway/Ontario bug. I have a Dhall package that takes away most of the pain,
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however it's not flexible enough to describe the entire scope of what my
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services need to do (IE: pinging Google/Bing to update their indexes on each
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deploy), and I don't feel like putting in the time to make it that flexible.
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[This is the regex for determining what is a valid boolean value in YAML:
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`y|Y|yes|Yes|YES|n|N|no|No|NO|true|True|TRUE|false|False|FALSE|on|On|ON|off|Off|OFF`.
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This can bite you eventually. See the <a
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href="https://hitchdev.com/strictyaml/why/implicit-typing-removed/">Norway
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Problem</a> for more information.](conversation://Mara/hacker)
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I have a tor hidden service endpoint for a few of my services. I have to use an
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[unmaintained tool](https://github.com/kragniz/tor-controller) to manage these
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on Kubernetes. It works _today_, but the Kubernetes operator API could change at
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any time (or the API this uses could be deprecated and removed without much
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warning) and leave me in the dust.
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I could live with all of this, however I don't really think it's the best idea
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going forward. There's a bunch of services that I added on top of Kubernetes
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that are dangerous to upgrade and very difficult (if not impossible) to
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downgrade when something goes wrong during the upgrade.
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One of the big things that I have with this setup that I would have to rebuild
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in NixOS is the continuous deployment setup. However I've done that before and
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it wouldn't really be that much of an issue to do it again.
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NixOS fixes all the jank I mentioned above by making my specifications not have
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to include the version numbers of everything the system already provides. You
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can _actually trust the package repos to have up to date packages_. I don't
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have to go around and bump the versions of shims and pray they work, because
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with NixOS I don't need them anymore.
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## Option 2: NixOS on top of SoYouStart or Kimsufi
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This is a doable option. The main problem here would be doing the provision
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step. SoYouStart and Kimsufi (both are offshoot/discount brands of OVH) have
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very little in terms of customization of machine config. They work best when you
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are using "normal" distributions like Ubuntu or CentOS and leave them be. I
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would want to run NixOS on it and would have to do several trial and error runs
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with a tool such as [nixos-infect](https://github.com/elitak/nixos-infect) to
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assimilate the server into running NixOS.
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With this option I would get the most storage out of any other option by far. 4
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TB is a _lot_ of space. However, SoYouStart and Kimsufi run decade-old hardware
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at best. I would end up paying a lot for very little in the CPU department. For
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most things I am sure this would be fine, however some of my services can have
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CPU needs that might exceed what second-generation Xeons can provide.
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SoYouStart and Kimsufi have weird kernel versions though. The last SoYouStart
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dedi I used ran Fedora and was gimped with a grsec kernel by default. I had to
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end up writing [this gem of a systemd service on
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boot](https://github.com/Xe/dotfiles/blob/master/ansible/roles/soyoustart/files/conditional-kexec.sh)
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which did a [`kexec`](https://en.wikipedia.org/wiki/Kexec) to boot into a
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non-gimped kernel on boot. It was a huge hack and somehow worked every time. I
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was still afraid to reboot the machine though.
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Sure is a lot of ram for the cost though.
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## Option 3: NixOS on top of Digital Ocean
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This shares most of the problems as the SoYouStart or Kimsufi nodes. However,
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nixos-infect is known to have a higher success rate on Digital Ocean droplets.
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It would be really nice if Digital Ocean let you upload arbitrary ISO files and
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go from there, but that is apparently not the world we live in.
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8 GB of ram would be _way more than enough_ for what I am doing with these
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services.
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## Option 4: NixOS on top of Vultr
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Vultr is probably my top pick for this. You can upload an arbitrary ISO file,
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kick off your VPS from it and install it like normal. I have a little shell
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server shared between some friends built on top of such a Vultr node. It works
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beautifully.
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The fact that it has the same cost as the Digital Ocean droplet just adds to the
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perfection of this option.
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## Costs
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Here is the cost table I've drawn up while comparing these options:
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| Option | Ram | Disk | Cost per month | Hacks |
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| :--------- | :----------------- | :------------------------------------ | :-------------- | :----------- |
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| Do nothing | 6 GB (4 GB usable) | Not really usable, volumes cost extra | $60/month | Very Yes |
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| SoYouStart | 32 GB | 2x2TB SAS | $40/month | Yes |
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| Kimsufi | 32 GB | 2x2TB SAS | $35/month | Yes |
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| Digital Ocean | 8 GB | 160 GB SSD | $40/month | On provision |
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| Vultr | 8 GB | 160 GB SSD | $40/month | No |
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I think I am going to go with the Vultr option. I will need to modernize some of
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my services to support being deployed in NixOS in order to do this, however I
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think that I will end up creating a more robust setup in the process. At least I
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will create a setup that allows me to more easily maintain my own backups rather
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than just relying on DigitalOcean snapshots and praying like I do with the
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Kubernetes setup.
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Thanks farcaller, Marbles, John Rinehart and others for reviewing this post
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prior to it being published.
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