If you are deploying OpenShift on IBM Power and encountering failures during the node-image pull, you are likely hitting a known capacity limit in the temporary filesystem.
The Problem
In recent 4.x builds (specifically identified in OCPBUGS-70168), the default 4GiB allocation for /var/ostreecontainer in tmpfs is not enough for Power architectures. As the node-image attempts to pull and pivot to the latest operating system levels, it falls short by approximately 200MiB.
The failure manifests in the logs as a “min-free-space” error:
error: Writing content object: min-free-space-percent '3%' would be exceeded...
The Solution: Manual Remount
While PR #10304 is being reviewed and merged, you can resolve this manually by increasing the size of the mount.
When to apply: This must be executed early in the boot process, specifically after the tmpfs is initialized but before the node-image-pull.sh script attempts to fetch the release layers.
sudo mount -o remount,size=5G /var/ostreecontainer
Key Considerations
- Memory Usage: Increasing this limit “steals” an additional 1GB from main system memory. Ensure your LPAR or VM has enough overhead to accommodate this temporary spike.
- Persistence: This is a volatile change to
tmpfs. Once the node pivots and reboots into the new image, the temporary filesystem is cleared.
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