Cri File System Tools Install -

# Add Kubernetes repository (contains cri-tools)
sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.30/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt-get update
sudo apt-get install -y cri-tools

sudo dnf groupinstall "Development Tools" sudo dnf install git fuse3-devel protobuf-devel protobuf-c-devel libnl3-devel libcap-devel

mkdir /tmp/mycontainer
crifs mycontainer-image:latest /tmp/mycontainer
ls -la /tmp/mycontainer
fusermount -u /tmp/mycontainer

# Check disk usage of runtime directory
du -sh /var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/
# Clean unused images
crictl rmi --prune

git clone https://github.com/checkpoint-restore/criu.git
cd criu
make
sudo make install

The criu tool includes powerful filesystem-related commands such as: cri file system tools install

If you find orphaned overlay mounts (findmnt | grep overlay shows many old pods): sudo dnf groupinstall "Development Tools" sudo dnf install

# List container mounts still in kernel but not in CRI state
crictl ps -aq | xargs crictl inspect | jq '.info.pid' | xargs -I{} ls -l /proc/{}/mountinfo
| Tool | Purpose | Install |
|------|---------|---------|
| skopeo | Inspect image filesystem layers without pulling | sudo apt install skopeo |
| umoci | Low-level OCI image filesystem unpacker | Download from GitHub releases |
| runc | Runtime filesystem exec/debug | Usually bundled with containerd |
| nsenter | Enter container mount namespace | Part of util-linux | cri file system tools install
Example: umoci to unpack image rootfs
umoci unpack --image docker://alpine:latest /tmp/alpine-rootfs
tree /tmp/alpine-rootfs/rootfs