The syntax generally looks like this:
# Create a directory to mount to
mkdir /tmp/myimage
# Mount the image (example using a stargz-compressed image)
crfs mount docker://registry.example.com/myimage:latest /tmp/myimage
Note: CRFS works best with images compressed in the "stargz" format, which is an extension of the standard tar.gz format optimized for random access.
CRI-O uses storage package (from containers/storage) with tools like: cri file system tools link
In the world of containerized applications, the storage layer is often treated as a black box. Developers run docker run or kubectl apply, and somehow, the files appear. But beneath the surface lies a sophisticated ecosystem of snapshots, layers, and mount points. For those managing Kubernetes clusters using the Container Runtime Interface (CRI), understanding CRI file system tools and the critical role of the link (symbolic or hard link) is not just an advanced skill—it is a necessity for debugging, performance tuning, and disaster recovery.
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. The syntax generally looks like this: # Create
If your cluster uses containerd, ctr provides direct access to namespaces and snapshots.
Filesystem link operations:
ctr namespace ls # List namespaces (e.g., k8s.io)
ctr -n k8s.io snapshot ls # Show all snapshots (image layers)
ctr -n k8s.io snapshot mount <key> /mnt # Mount a snapshot to inspect
Why linking matters here: Snapshots are immutable directories linked together via overlayfs. Each snapshot has a "parent" link to the previous layer.
nsenter -t <pid> -m bash