Johannes Kastl

https://digitalcourage.social/@johanneskastl

Senior Cloud Engineer at ATVANTAGE, Munich

Opinions are my own. Crude sense of humour also my own.

Nerd, music lover, photographer, musician, husband, dad, vegetarian, environmentalist, anti-racist, feminist, sysadmin, open source enthusiast.
Loves classical movie scores.

Pronouns: He/Him
Open Source rocks.: Do you?
Save the planet!: Now!
Homepage: https://johannes-kastl.de

Public Key

npub1ayt0pcv55hcgf5emehtntmfpaev8ulnksjts7ws2cr7q2d6kn0lskdh6nx

NIP-05 Address

johanneskastl_at_digitalcourage.social@momostr.pink

Profile Code

nprofile1qqswj9hsux22tuyy6vaum4e4a5s7ukr70emgf9c08g9vplq9xatfhlcprpmhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmntv2tzau

Publishing to

relay.momostr.pink

Author Public Key

npub1ayt0pcv55hcgf5emehtntmfpaev8ulnksjts7ws2cr7q2d6kn0lskdh6nx

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Last Notes

2026-08-25 08:43:30 UTC

Dear Fediverse,
for a small one-person-company I am looking for a hosted or self-hostable solution to allow customers to see a calendar in "Free/Busy" mode? And maybe even allow them to schedule an appointment in said calendar themselves?
I have never used it, but I think Calendly is doing something like that. Any experiences? Any alternatives that are worth checking out?
A Nextcloud is available, but from what I found does not offer that feature (yet?).
Thanks Fedi!
#SelfHosting #FLOSS #AskFedi #Calendar

2026-06-14 15:58:26 UTC

Dear Linux games, I need your help.
My son's gaming pc sometimes hangs up. The screens go black and into standby, all fans go off, but the power LED stays. Both the reset and the power button on the case have no effect at all. The only thing that works is completely cutting the power (via the power supply's on/off switch) and waiting for half a minute. Then we can turn it on again without issues.
- The buttons are working in general, i.e. unless those blackscreens occur we can power on/off or reset the machine without issues
- Memtest did not find errors
- Exchanging the RADEON GPU did not change anyhting
- New linux user account: no change
- The SSDs are fine (smartctl)
I have been building my own PCs for 25 years and never had an issue like this. Especially as the hardware buttons do no longer work, that completely confuses me.
OS is Nobara Linux 43. The freezes seem to happen most often when starting a game in Steam (or re-joining a game).
#linux #gaming #GamingOnLinux #Fedora #Steam #fedihelp #wtf

2026-05-18 17:49:15 UTC

Does anyone have a recommendation for a KVM switch for 3 machines? Unfortunately the machines only have Displayport and VGA, no HDMI. I find lots of cheap HDMI switches, but only very pricy ones with Displayport. And the monitor in question does no longer have VGA input...
And needing 3 ports makes it even more expensive... :-(
#HomeLab #SelfHosting #KVMSwitch

2026-03-15 12:16:38 UTC

Question for the haproxy users:
Does anyone have a working configuration for reverse-proxying HTTPS URLs
- using "mode tcp" (no TLS certificates on the Haproxy) AND
- using the "use_backend" configuration do decide which backend to use based on SNI?
So we have https://foo.example.org and https://bar.example.org, both DNS entries pointing to the haproxy.
use_backend foo if { FOO_CONDITION_GOES_HERE }
use_backend bar if { BAR_CONDITION_GOES_HERE }
default_backend foo
No matter which condition we try, we always fall back to the default backend.
Removing the `default_backend` we get errors for all connection attempts. So clearly the conditions are wrong.
We tried `req_ssl_cni foo.example.org` as the condition inside the curly braces.
We tried `ssl_fc_sni_end foo.example.org`.
We tried `req.ssl_cni foo.example.org`.
We tried with -i and with "-m end".
We tried the complete URL (some.service.foo.example.org) or only the domain.
Any ideas, anyone?
#Haproxy #TLS #Linux #Admin #homelab #DevOps #ReverseProxy

2025-12-20 11:46:17 UTC

Liebes Fediverse,
was empfehle ich einer jungen Selbstständigen denn als einfaches, günstiges und datenschutzfreundliches Angebot (EU oder DE) für einen E-Mail-Newsletter?
Eigene Domain ist vorhanden.
Kann #mailbox_org das vielleicht direkt?
Vielen Dank!
(Ich meine jetzt nicht Mailman o. ä. sondern einen Dienst, der das macht)
#Newsletter #Datenschutz #Privacy

2025-05-21 16:05:18 UTC

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Try AlmaLinux. Stable, rock solid. Works like a charm.
(Or go immutable with #Fedora #CoreOS or #openSUSE #MicroOS)

2025-03-31 16:49:28 UTC

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OK, this seems to be the python that Ansible is using. Being called directly without all the PATH mangling that the .ansible-wrapped script does. Which explains why it does not find the kubernetes module...
(Thanks @darix for the hint)
#NixOS #Ansible #Python #wtf

2025-03-31 16:38:55 UTC

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Running the playbook with -v shows me that it is using a completely different python3 from /nix/store/lhpwdis5hkyljz1d200bj1s6g51ljq9k-python3-3.12.8/bin/python3 which does not have the kubernetes module apparently.
No idea how it picks this up, where it takes that information from and how to fix this...
#NixOS #Ansible #python

2025-03-31 16:14:18 UTC

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Fourth and hopefully last round for the #NixOS #Ansible bubble:
Short recap: Having the kubernetes module in the ansible derivation/package is not enough, it needs to also be in the python3 or python312 derivation/package.
Fun fact:
- `which python3` gives me /home/tux.penguin/.nix-profile/bin/python3
- this links to /nix/store/ipwx571dlhxmdf1n1yd8vgqq5ndjnxba-python3-3.12.8-env/bin/python3
- `which -a python3` only gives me this one python, no other binaries found in the PATH with that name
1. Using /nix/store/ipwx571dlhxmdf1n1yd8vgqq5ndjnxba-python3-3.12.8-env/bin/python3 as ansible_python_interpreter works, the kubernetes module is found
2. Using /home/tux.penguin/.nix-profile/bin/python3 for ansible_python_interpreter works
3. Using "{{ lookup('env','HOME') }}/.nix-profile/bin/python3" for ansible_python_interpreter works
4. Using just python3 DOES NOT work?!?!? What the hell? Even if this is resolved (in the shell at least) to the same python3 binary/link in ~/.nix-profile/bin/python3? What the hell?

2025-03-30 17:16:58 UTC

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Third round for the #NixOS #Ansible bubble:
I think I have a solution! At least I got some thing working.
Having the python312 nixpkg installed is not enough. It is also not enough to have python312, python312Packages.kubernetes and python312Packages.cryptography installed.
I had to install them "in the same package":
```
home.packages = with pkgs; [
ansible
ansible-lint
(pkgs.python3.withPackages (python-pkgs: [
python-pkgs.cryptography
python-pkgs.kubernetes
]))
];
```
Then I could set the ansible_python_interpreter to `python3` and could use the kubernetes python module for using things from the kubernetes.core Ansible collection.
This is in addition to having the modules also available in the ansible derivation, no idea if that is really necessary.
I'll do some more digging and testing, but at least something worked now! I call that a win!
# NixOS #Ansible #Python #hellyeah

2025-03-30 13:41:05 UTC

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Second round for the #NixOS #Ansible bubble:
With lots of help I now have a Ansible derivation that includes python modules for requirements from e.g. the kubernetes.core Ansible collection.
But things still do not work. Example: Creating something in a Kubernetes cluster using the kubernetes.core collection. No matter whether I target localhost in my playbook or the remote host with a delegate_to for localhost.
Ansible uses the installed python directly, but without all the module-including-voodoo that is done in the .ansible-wrapped file (that is being called when "ansible" is being invoked". And thus the kubernetes module is not found.
I also tried installing python3 and python3Packages.kubernetes in addition to ansible. I see the kubernetes in $HOME/.nix-profile/lib/python3.12/site-packages/, but it is still not found. I tried telling Ansible that localhost has a python interpreter, but no change.
Frustrating...

2025-03-29 21:02:07 UTC

Fun question for the #NixOS #Ansible bubble:
I noticed that Ansible on NixOS does not find python modules that have been installed from NixPkgs. This means, modules like the kubernetes module are not found and Ansible cannot do its work, when a task is executed on localhost (e.g. via delegate_to)
Is there a way to install those additional modules together with the Ansible package?
Or is this just some messup with autodetecting the python interpreter on localhost?
#python #Ansible #NixOS

2025-03-03 13:37:42 UTC

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Hmmm. How are your monitors connected? Daisy chaining via DisplayPort?

2025-03-03 07:34:27 UTC

Dear #kde #plasma users,
does anyone else notice that switching applications using Alt+TAB is behaving funnily? I think this might be since Plasma6, but I noticed it more prominently in the last couple of weeks.
Previously, Alt+TAB, then releasing, then Alt+TAB would switch between two applications. The current one and the last one. You could do so forever.
Now, the one before the current one is sometimes skipped and I get a third one selected. Of course, this does **NOT** happen reproducibly. I can rule out fat-fingering and also hardware issues like broken keys, as this happens on more than one laptop with more than one external keyboard.
#openSUSE #Tumbleweed with 6.3, #Fedora #Kinoite with 6.3, #NixOS 24.11 with 6.1

2024-12-15 14:16:39 UTC

#Darts world championship 2025 starts today!

2024-11-18 18:04:41 UTC

Is anyone using #ipv6 in #podman? Especially on a #Linux server or VM that gets a /64 #subnet delegated from the provider?
If so, any good tutorials for Podman 5.x?

2024-11-07 21:20:26 UTC

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Thanks for the explanation!

2024-11-07 20:05:54 UTC

@npub1kwa…e0nj I just updated my pixel6 and noticed that there are two rounds of app optimizations. One before entering SIM pin and device pin, the other one after that. Is this intentional?

2024-09-24 16:55:05 UTC

I had some time to finally read #GregGraffin's memoir Punk Paradox.
As Bad Religion has been a huge influence to me over the years and is one of the main reasons I had to quickly increase my English vocabulary it is really fascinating to read his side of the story and connect some dots.
Highly recommended.
https://digitalcourage.social/system/media_attachments/files/113/193/558/747/532/258/original/8152957a93b01580.jpg

2024-09-20 16:36:05 UTC

Today I would like to thank the lovely people that build #openSUSE and the #OpenBuildService @npub1fvx…zgdk and those that contribute to @opensuse by maintaining packages.
And of course all the maintainers of the projects and tools. There are too many to mention.
Have a nice weekend everyone.
#linux #thankyourmaintainers

2024-08-19 15:18:46 UTC

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Thanks for the insights! Unreliable restore is a no-go!

2024-08-18 05:50:38 UTC

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I have not used Seedvault, will take a look...

2024-08-17 18:13:20 UTC

The year is 2024. You still can not #backup a #android device properly and completely without crude hacks.
Or can you?

2024-07-18 17:23:47 UTC

I just finished reading the #EltonJohn autobiography "Me". Very entertaining.
https://digitalcourage.social/system/media_attachments/files/112/808/647/754/344/663/original/08ba514e82039754.jpg

2023-05-20 06:43:44 UTC

"Grokking continuous delivery" by Christie Wilson
Wow, what an incredibly interesting and well written book. Not only usable for software development, but also a good read for #InfrastructureasCode or #GitOps approaches or similar.
And I am not even finished with it, still have part 4 to enjoy...
https://digitalcourage.social/system/media_attachments/files/110/399/637/496/595/803/original/64bf40e05f0e628a.jpg