Cri File System - Tools Install
| 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 |
Example: umoci to unpack image rootfs
umoci unpack --image docker://alpine:latest /tmp/alpine-rootfs
tree /tmp/alpine-rootfs/rootfs
crifs /var/lib/postgresql/data /mnt/db_backup -o ro rsync -a /mnt/db_backup /backup/location/ cri file system tools install
To install the correct tools, first identify your CRI runtime.
| Runtime | CRI Socket | Default CLI Tools |
| :--- | :--- | :--- |
| containerd | /run/containerd/containerd.sock | ctr, nerdctl, crictl |
| CRI-O | /run/crio/crio.sock | crictl, podman |
| Docker (via cri-dockerd) | /run/cri-dockerd.sock | crictl (limited) | | Tool | Purpose | Install | |------|---------|---------|
Run:
ps aux | grep -E "containerd|crio|dockerd"
| Tool | Purpose |
| :--- | :--- |
| nydus-image | Creates/converts RAFS (Registry Acceleration File System) images. |
| nydusd | The daemon that mounts the filesystem (usually via FUSE or virtiofs). |
| nydusify | CLI tool to convert Docker images into Nydus format. |
| containerd-nydus-grpc | The plugin that bridges containerd and the Nydus daemon. | cri file system tools install
Since package availability for cri-dockerd varies wildly between distros, building from source is often the most consistent method.
# Clone the repository
git clone https://github.com/Mirantis/cri-dockerd.git
cd cri-dockerd
# Add Kubernetes apt repository
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