| 4 Sep 2023 |
 hexa | ajs124: maybe something hydra does? | 13:38:01 |
 ajs124 | don't think that's a hydra thing. more like some strange config on the hydra build nodes. | 13:38:56 |
| hexa | yeah, trying to find that config as we speak | 13:39:19 |
| hexa | I think we're using https://github.com/DeterminateSystems/nix-netboot-serve to serve netboot images | 13:40:15 |
| hexa | runs on eris apparently | 13:40:46 |
| hexa | wondering if our runner configs are private? | 14:03:42 |
| hexa | or state on eris even | 14:03:45 |
| hexa | the nix-netboot-serve configures is too minimal | 14:05:49 |
| hexa | https://github.com/NixOS/equinix-metal-builders/blob/main/modules/nix.nix#L34 | 14:22:06 |
| hexa | there is a hard fdlimit on the nix-daemon | 14:22:18 |
 vcunat | A million (per process) sounds quite a lot. | 14:42:54 |
| vcunat | Unless some bad leak happens. Maybe it's more likely that it's stuck on a low soft limit or that it doesn't propagate as we'd expect. | 14:43:44 |
 nbp | I wish we could have a wireguard-boot, where one image would connect using wireguard to download its latest image. This way we could make it work without having to redo the DHCP of the network. | 15:11:38 |
| hexa |
Nowadays, the hard limit defaults to 524288, a very high value compared to historical defaults. Typically applications should increase their soft limit to the hard limit on their own, if they are OK with working with file descriptors above 1023, i.e. do not use select(2).
| 15:12:14 |
| hexa | I think knowing what number of open fds we're having on the builders would be an easy first step | 15:21:40 |
 K900 ⚡️ | In reply to @vcunat:matrix.org
A million (per process) sounds quite a lot. It's not per process though | 15:22:43 |
| K900 ⚡️ | It's per cgroup | 15:22:46 |
| K900 ⚡️ | And everything is in the cgroup | 15:22:53 |
| vcunat | Can you point me to docs about that? | 15:27:52 |
| K900 ⚡️ | Uh, it's in systemd docs somewhere | 15:28:11 |
| vcunat | I really thought that setrlimit is per-process and I can't quickly find a reference. | 15:28:15 |
| nbp | I recall this could be done on the command line, but I forgot the command since. | 15:28:50 |
| vcunat | systemd docs about that limit says
Note that most process resource limits configured with these options are per-process
| 15:28:55 |
| vcunat | man systemd.exec.5 | 15:29:06 |
| vcunat | In reply to @nbp:mozilla.org
I recall this could be done on the command line, but I forgot the command since. ulimit -n uses the same syscall | 15:30:41 |
| K900 ⚡️ | In reply to @vcunat:matrix.org
I really thought that setrlimit is per-process and I can't quickly find a reference. setrlimit yes but I think systemd does some fancier cgroup stuff | 15:30:47 |
| K900 ⚡️ | Not 100% sure though | 15:30:57 |
| vcunat |
Set soft and hard limits on various resources for executed processes. See setrlimit(2) for
| 15:31:06 |
| vcunat | *
Set soft and hard limits on various resources for executed processes. See setrlimit(2) for [...]
| 15:31:29 |
| hexa | so what does that mean? | 15:32:32 |
