# See all overlay mounts on the system findmnt -t overlay cat /proc/mounts | grep overlay | grep <container-id>
The output shows a complex chain of lowerdir=layer1:layer2:image , which is the filesystem-level between the read-only image layers and the writable container layer. 4.2 Disk Usage Tools – du and ncdu Containers leak storage. Every Cri command that pulls an image, creates a layer, or writes logs consumes inodes. To diagnose "No space left on device" (ENOSPC) in Kubernetes, you must trace the link between the pod and its storage: cri file system tools link
# Find the top 10 largest container rootfs directories du -sh /var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/*/fs | sort -h If a node crashes, the underlying filesystem containing CRI directories may corrupt. You cannot run fsck on a mounted device. The link here is to unmount the CRI storage partition (often /var/lib/containerd ) first: # See all overlay mounts on the system
In the modern world of cloud-native computing, containers are ephemeral, but data is eternal. The bridge between a container’s short lifespan and persistent storage is the Container Runtime Interface (CRI) . For DevOps engineers, SREs, and system administrators, understanding the "CRI file system tools link" —the relationship between the CRI specification and the underlying filesystem management utilities—is not just a technical curiosity; it is a necessity for debugging, security, and performance tuning. To diagnose "No space left on device" (ENOSPC)
# List all containers and their mount points crictl ps -a crictl inspect <container-id> | jq '.info.runtimeSpec.mounts' Get the PID of a container – essential for nsenter into its filesystem crictl inspect <container-id> | jq '.info.pid'