This issue was exposed when using sandbox_path volume to support shared volume for nested containers under one task group. Here is a scenario:
The agent process runs as 'root' user, while the framework user is set as 'nobody'. No matter the commandinfo user is set or not, any non-root user cannot access the sandbox_path volume (e.g., a PARENT sandbox_path volume is not writable from a nested container). This is because the source path at the parent sandbox level is created by the agent process (aka root in this case).
While the operator is responsible for guaranteeing a nested container should have permission to write to its sandbox path volume at its parent's sandbox, we should guarantee the source path created at parent's sandbox should be set as the same ownership as this sandbox's ownership.