The default systemd user service configuration (10-oomd-user-service-defaults.conf)
sets ManagedOOMMemoryPressure=kill with ManagedOOMMemoryPressureLimit=50%.
Under parallel DinD load (6 molecule tests), memory pressure exceeds 50%
for 30 seconds, causing systemd-oomd to SIGKILL molecule containers
(rc=137). This was the root cause of recurring "container is not running"
and "Failed to create temporary directory" errors in CI.
Fix: Create a per-user systemd override that sets:
- ManagedOOMMemoryPressure=auto (don't kill on pressure)
- ManagedOOMMemoryPressureLimit=100% (never trigger)
- OOMScoreAdjust=-500 (very unlikely to be OOM-killed)
The runner users run Docker-in-Docker workloads that legitimately use
large amounts of memory. systemd-oomd's aggressive memory pressure
killing is inappropriate for CI runner workloads.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
