Fedora CoreOS - kernel parameters

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1

Hi there - I see in the documentation how to change kernel parameters using kargs

sudo rpm-ostree kargs --append=KEY=VALUE

I’m seeing an error when I attempt to launch a container:
Cannot raise FD limit to 8035, limit is 1024

So, researching a little, this can be fixed by changing the ulimit.

If I am to change the kernel param to ulimit=unlimited would that just simply be
sudo rpm-ostree kargs --append='ulimit=unlimited?

I did that and I still see the same error.

Perhaps I am looking at the wrong thing. Probably not the place to set ulimit.

Anyone? Thanks much!

2

Did you reboot after you ran the command? rpm-ostree by default doesn’t make changes to the running system.

I would verify you’ve rebooted. If you’re still having trouble can you run the following commands and post the output?

  • rpm-ostree status
  • cat /proc/cmdline
3

You don’t need to change kernel arguments to change those limits. You should use ulimit or edit /etc/security.conf: How do I change the number of open files limit in Linux? - Stack Overflow

What command are you using here?

2 Likes
4

I removed the kernel setting that I put in.
It’s back to the original now from when I first set up - with the exception of tcpdump. I saw a tutorial.

cat /proc/cmdline
BOOT_IMAGE=(hd0,gpt3)/ostree/fedora-coreos-28b76cc9892571c262d30d8ac044685351f4401a070ce8f0d0ce0e0a95b117f2/vmlinuz-6.2.13-300.fc38.x86_64 mitigations=auto,nosmt ignition.platform.id=virtualbox console=ttyS0,115200n8 console=tty0 root=UUID=cbd699b4-1f6d-41a5-90e9-c28decc76ec0 rw rootflags=prjquota boot=UUID=87c3cc68-bace-4fa1-bbc2-01563d295d94 ostree=/ostree/boot.0/fedora-coreos/28b76cc9892571c262d30d8ac044685351f4401a070ce8f0d0ce0e0a95b117f2/0
[core@localhost ~]$ rpm-ostree status
State: idle
AutomaticUpdatesDriver: Zincati
  DriverState: active; periodically polling for updates (last checked Thu 2023-05-25 21:54:21 UTC)
Deployments:
● fedora:fedora/x86_64/coreos/stable
                  Version: 38.20230430.3.1 (2023-05-15T21:32:02Z)
               BaseCommit: e7109bec01fdc47125e43fca01b9817d2371557a019bbcfc6a45527c93a23f98
             GPGSignature: Valid signature by 6A51BBABBA3D5467B6171221809A8D7CEB10B464
          LayeredPackages: tcpdump

  fedora:fedora/x86_64/coreos/stable
                  Version: 38.20230430.3.1 (2023-05-15T21:32:02Z)
               BaseCommit: e7109bec01fdc47125e43fca01b9817d2371557a019bbcfc6a45527c93a23f98
             GPGSignature: Valid signature by 6A51BBABBA3D5467B6171221809A8D7CEB10B464
          LayeredPackages: tcpdump
5

Timothy - I am attempting to run a Docker container.
I am getting that error when running the container

sudo docker run -d --name haproxy-ce-file haproxytech/haproxy-debian
 docker logs -f b18752a4292e
[NOTICE]   (1) : haproxy version is 2.7.8-58c657f
[NOTICE]   (1) : path to executable is /usr/local/sbin/haproxy
[ALERT]    (1) : [haproxy.main()] Cannot raise FD limit to 8035, limit is 1024.

I’m wondering if this error is coming from Docker and not Fedora CoreOS - am I looking in the wrong places?