This article explores the relationship between CRI-compliant runtimes (containerd and CRI-O), the filesystem tools that manipulate container storage, and how the humble link (both symbolic and hard) functions as the architectural glue holding container layers together. Before diving into tools and links, we must establish a baseline. The CRI is a Kubernetes API that kubelet uses to communicate with container runtimes. It abstracts the runtime implementation, allowing Kubernetes to work with Docker (via dockershim, now deprecated), containerd, CRI-O, and others.
crictl images # Lists images with their IDs and sizes crictl inspect <container-id> # Shows detailed mount points and layer paths crictl imagefsinfo # Reports filesystem usage for image storage The inspect command reveals the rootfs path—a symbolic link that points to the container’s writable layer. For example: cri file system tools link
Also, the new feature (v1.25+) uses hard links to preserve container state before migration. Conclusion: The Link is the Lost Art of Container Storage The CRI file system tools — crictl , ctr , crio-status —give you x-ray vision into how Kubernetes manages storage. But without understanding the link (whether symbolic, hard, or the conceptual parent pointer between layers), you are blind to half of the system. Conclusion: The Link is the Lost Art of
/var/lib/containers/storage/overlay/<layer-id>/merged -> /var/lib/containers/storage/overlay/<layer-id>/../<parent-id>/merged Scenario 1: "No such file or directory" inside a container Even though the file exists in the image, the container cannot see it. This is often due to a broken symbolic link in a lower layer . the container cannot see it.