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Spurious error message at boot due to module not loaded early
Resolved (N/A)PublicBUG

Description

SUMMARY

On booting the router, systemd-sysctl emits an error message, as it tries to write a sysctl to a location held by a module not yet loaded.

STEPS TO REPRODUCE

  1. Boot the router
  2. Run the following command:
show log all | match systemd-sysctl

OBSERVED RESULT

vyos@vyos:~$ show log all | match systemd-sysctl
Feb 18 06:03:39 localhost systemd-sysctl[341]: Couldn't write '1' to 'net/netfilter/nf_conntrack_helper', ignoring: No such file or directory

EXPECTED RESULT

No output.

SOFTWARE/OS VERSIONS

VyOS 1.4-rolling-202102180218

ADDITIONAL INFORMATION

This is due to the nf_conntrack module not being loaded by the time systemd-sysctl runs:

vyos@vyos:~$ sudo grep -r nf_conntrack /etc/modules-load.d/
vyos@vyos:~$ sudo grep -r nf_conntrack_helper /etc/sysctl.d/
/etc/sysctl.d/30-vyos-router.conf:net.netfilter.nf_conntrack_helper=1

The obvious solution is to add a file in /etc/modules-load.d to load that module. Or maybe to remove the sysctl entirely, as when the router is booted, the value is correct anyway:

vyos@vyos:~$ sudo sysctl net.netfilter.nf_conntrack_helper
net.netfilter.nf_conntrack_helper = 1

Details

Difficulty level
Easy (less than an hour)
Version
1.4-rolling-202102180218
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Perfectly compatible

Event Timeline

dmbaturin added a subscriber: dmbaturin.

I haven't seen this error in a long while, so I suppose it's fixed.