Re: How to increase hard NOFILE limit in debian 11?
On Mon, Nov 14, 2022 at 06:50:53AM -0800, Thomas Nyberg wrote:
> Thanks for the help! That worked well with bash (i.e. if I set both
> /etc/security/limits.conf and /etc/sysctl.conf, then `ulimit -aH` returns
> what you'd expect).
>
> However, I have a server process and when I check its limits by looking at
> `/proc/$PID/limits`, the hard limit is not raised there. I have figured out
> that I can raise it by executing e.g. `prlimit --pid=$PID
> --nofile=1024:16777216`, but I haven't found a way for it to make it stick
> across reboots. The process itself is running as root.
Resource limits are inherited from one's parent process. So, you need
to figure out the full chain of processes leading up to your service.
If it's run by systemd, then the chain should be relatively short --
systemd runs with the limits are placed by the kernel, followed by
whatever adjustments systemd makes to itself internally. Then it
reads a service unit file, and spawns your service according to the
instructions therein.
The unit file can include resource limit declarations. See systemd.exec(5)
and search for PROCESS PROPERTIES.
If it's *not* a systemd unit file, or if you're not using systemd at
all, then the chain of processes can be longer. There could be a shell
involved, for example. You'd need to check for resource limits being
applied at each step.
It should be noted that /etc/security/limits.conf will almost certainly
do nothing for services. It's a configuration file for pam_limits, which
is generally used for login type things. Not services.
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