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