Don't touch sysctls set in sysctl.conf #518
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Currently reapply_sysctl=1 will cause sysctl.conf(5) and sysctl.d(5) to be loaded and all the sysctls configured set after sysctls that TuneD decides to set. There are some issues with this approach I'll address in a follow-up commit. This one (hopefully) doesn't change the behavior. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Without TuneD, sysctls from sysctl.conf(5) are set once early on boot, typically via systemd-sysctl.service(8) or a similar service. TuneD, however, with reapply_sysctl=1 (which is default), applies these settings later on during startup and on other occassions as well. This is rather unfortunate, because it changes the semantics of sysctl.conf(5). Without TuneD, the configured values serve as mere defaults while with TuneD their values are maintained as configured. This has been reported to break things [1] in case of an user who has configured net.ipv6.conf.*.disable_ipv6=1 in sysctl.conf and the used a different tool (NetworkManager) to override it later on, essentially ending up with tools racing for setting the sysctl. [1] https://bugzilla.redhat.com/show_bug.cgi?id=2136749 Let's be a little less aggresive here and just avoid touching the explicitly configured sysctls. Preserve the old behavior for compatibility's sake, but turn it off by default. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
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Marked as draft since it seems I need to fix tests first. Also sorry about the s/tuned/teamd/ in branch name, it's due to brain rot from my dealings with teamd. Edit: un-marking as draft, since the tests passed, meaning this is probably the best branch ever |
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TuneD reverting sysctls to values configured in sysctl.conf was reported to have made one fine gentleman very sad.
The individual commits contains more details & a proposed remedy.