ulimit in self-hosted runner's shell mismatch the ulimit set in machine

[igorluppi]

Describe the bug
When ulimit -a is performed in regular machine' shell we got:

POSIX message queues (bytes, -q) 4194304

But Github runners are limiting it to another value. If we run the same command in runner shell:

POSIX message queues (bytes, -q) 819200

The runner is installed in the same machine, although it cannot use the same resource as set.

In our /etc/security/limits.conf we have:

* hard msgqueue 4194304
<$USER> hard msgqueue 4194304
root hard msgqueue 4194304
* soft msgqueue 4194304
<$USER> soft msgqueue 4194304
root soft msgqueue 4194304

How can Github self-hosted runner access the same amount of memory?

To Reproduce
Just run ulimit -a in Github runner shell, if you have changed the default value for the desired ulimit.

Expected behavior
When we run ulimit -a we should see POSIX message queues (bytes, -q) 4194304

Actual behavior
When we run ulimit -a we see POSIX message queues (bytes, -q) 819200

Runner Version and Platform

Version of your runner? Current runner version: '2.317.0'

OS of the machine running the runner? Ubuntu 22.04

What's not working?

> Run ulimit -q 4194304
ulimit -q 4194304 
Error: Process completed with exit code 1.

[polarathene]

In our /etc/security/limits.conf we have

Limits are often managed by systemd now IIRC. This has been the case at least for file descriptors where the default limits (at least for root?) are set to 1024 soft and 524288 hard. On Github CI runners these have been observed as 65536 for both IIRC.

Limits config you reference may be applicable to specific users, you've not shared much context about the self hosted runner regarding that.

See this reference, try grep the filesystem for LimitMSGQUEUE. I could be mistaken, just a hint as I ran into this sort of issue with Docker containers in the past where the limit varied based on distro and caused much confusion to troubleshoot the cause on misbehaving systems.

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[github-actions]

This issue was closed because it has been stalled for 15 days with no activity.