What is SystemD's default value for LimitNOFILE (on CentOS7)

Question

It seems like a very easy question but I couldn't find, what the default for services in SystemD for LimitNOFILE is.

Is there a file with global defaults?

Solution 1

systemd imposes no such limit by default. however pam_limits generally does, configuration file is /etc/security/limits.conf

Solution 2

#/etc/security/limits.conf
#This file sets the resource limits for the users logged in via PAM.
#It does not affect resource limits of the system services.
#if your program startup via systemctl
#config /etc/systemd/system.conf
DefaultLimitNOFILE=

Comments

[Martin Rauscher]

Thanks! So one could say that SystemD just overrides the ordinary Linux limits?

[Cristian Rodriguez]

Systemd is able to raise or decrease the system defaults, please see serverfault.com/questions/356962/… top comment for a longer more detailed explanation

[Leifb]

For us, systemd did impose this limit (ubuntu 18.04 and 20.04). We had all of our servers crash and changing LimitNOFILE to a high value did fix the problem. Limits in /etc/security/limits.conf were set high enough and increasing it alone did not fix the problem. Maybe it has been changed since 2015.