Add -C option for CPU quota limit on build containers #143
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Similar to the existing -M option for memory limits, this adds a -C option to set a CPU quota on the systemd-nspawn build containers. This is useful for rebuilderd setups where you want to limit CPU usage to prevent resource contention with other services on the same machine. Usage: repro -C 500% package.pkg.tar.zst # Limit to 5 CPU cores repro -C 1200% -M 24G package.pkg.tar.zst # 12 cores, 24GB RAM The CPU quota is passed to systemd-nspawn via --property="CPUQuota=...", which sets the cgroup cpu.max limit on the container. Environment variable MAX_CPU can also be used (e.g., in systemd service files): Environment=MAX_CPU=500%
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Foxboron
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Dec 25, 2025
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Foxboron
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Foxboron
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LGTM, but generally I suspect we should figure out if naming the systemd-nspawn session and/or advicing people to run this under systemd-run is better then trying to include all the different systemd options into repro.sh.
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Thanks! Yep, that makes sense for the future. If no other comments - would be great to have it merged and potential new release :) |
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Summary
This PR adds a
-Coption to set a CPU quota on systemd-nspawn build containers, similar to the existing-Moption for memory limits.Motivation
When running rebuilderd on a shared server, it's useful to limit CPU usage to prevent resource contention with other services. The existing
-Moption provides memory limits, but there's no equivalent for CPU.Changes
MAX_CPUenvironment variable support-C <value>command-line option (e.g.,-C 500%for 5 cores)--property="CPUQuota=..."Usage
Testing
Tested on Arch Linux with rebuilderd:
--property=CPUQuota=...argumentcpu.maxis correctly set (e.g.,500000 100000for 500%)