POC: Force writable image volumes using overlay filesystem#15
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antoine-gaillard wants to merge 3 commits into
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POC: Force writable image volumes using overlay filesystem#15antoine-gaillard wants to merge 3 commits into
antoine-gaillard wants to merge 3 commits into
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This is a proof-of-concept that makes all image volumes writable by: - Removing the readonly restriction check - Creating an overlay filesystem with: - Lower layer: Original read-only image content - Upper/Work layers: Writable directories for modifications - Setting the mount as non-readonly for containers The changes are isolated per container through separate upper/work directories. NOTE: This is a temporary POC implementation. Proper support requires: - Kubernetes API changes to support writable image volumes - Kubelet changes to pass the readonly flag correctly - Removal of the hardcoded forcing of writable mounts Changes made: - Skip readonly validation for image volumes - Create overlay filesystem for each image mount - Update cleanup logic to handle overlay directory structure - Force Readonly=false on mount spec for containers
- Fix snapshot key to use lowerDir consistently - Add tmpfs mounting for upper/work directories (4x image size, 256MB-32GB) - Create overlay subdirectories within tmpfs mounts - Add tmpfs cleanup in removal logic
Working writable image volumes with in-memory overlay. Add debug logging and fix snapshot preparation.
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This is a proof-of-concept that makes all image volumes writable by:
The changes are isolated per container through separate upper/work directories.
NOTE: This is a temporary POC implementation. Proper support requires:
Changes made: