I just spend few days debugging absolutely simple problem.
My servers wasn’t able to communicate after applying nftables rules with policy deny.
The rule was very simple:
iifname eth0 ip6 saddr @good ip6 daddr…
ChatGPT start to scare me (in a good sense). It really knows git, and it knows it better than me. This solution is absolutely from it, I had had no idea that there is a fast way.
I’ve missed this completely. Linux is exposing oom_kill value in the /proc/vmstat. It’s there since 2.6.36.
oom_kill
/proc/vmstat
It is read by node exporter as node_vmstat_oom_kill metric.
node_vmstat_oom_kill
Symptom: no lock screen under Gnome/Wayland. The rest of Gnome is functional.
Analysis: journalctl -b shows following lines:
journalctl -b
gsd-media-keys[3703]: \Couldn't lock screen…
You may think I’m rehearsing a Unix textbook from 1990s. Oh, you can run programs in parallel. How nice! What an amazing UNIX you have here!
Nope. This is a real problem I was struggling to solve.
Writing a routing daemon can be an interesting affair, especially when debugging it. Any bug can leave behind nastiness in your routes and routing rules, making it really hard to clean up. One technique to avoid such mess is to use an external server, but local debugging is…
I’m working on a special routing daemon which peeks into network namespaces a lot. I use pyroute2 library to manage routes, and my initial intention was to use NetNS facility in the pyroute2. Their approach to namespaces is to use a wrapper/helper, which spans a…
pyroute2
NetNS
Why do you need this? Because you have something different managing IP address on it. For example, pacemaker.
I’ve tried to find a way to gather metrics from iscsi TGT. I found nothing. No metrics, no exporters, no counters. Documentation is silent, internet is silent. It sounded like there is no metrics from tgt-admin or tgtadm or tgtd at all.