containerd Cheat Sheet 2026: ctr and nerdctl Commands

A quick reference for containerd — the industry-standard container runtime. Bookmark this page.

ctr (containerd CLI)

# List images
ctr images list
ctr -n k8s.io images list  # Kubernetes namespace

# Pull image
ctr images pull docker.io/library/nginx:alpine

# Run container
ctr run -d docker.io/library/nginx:alpine my-nginx

# List containers
ctr containers list
ctr -n k8s.io containers list

# List tasks (running processes)
ctr tasks list

# Execute in container
ctr tasks exec --exec-id shell my-nginx sh

# Stop and remove
ctr tasks kill my-nginx
ctr containers delete my-nginx

# Remove image
ctr images remove docker.io/library/nginx:alpine

Namespaces

# List namespaces
ctr namespaces list

# Create namespace
ctr namespaces create my-namespace

# Work in Kubernetes namespace
ctr -n k8s.io images list
ctr -n k8s.io containers list

Snapshots and Content

# List snapshots
ctr snapshots list

# View content store
ctr content list

# Check disk usage
ctr content ls | awk '{sum += $2} END {print sum/1024/1024 " MB"}'

Configuration

# /etc/containerd/config.toml

version = 2

[plugins."io.containerd.grpc.v1.cri"]
  sandbox_image = "registry.k8s.io/pause:3.9"
  
  [plugins."io.containerd.grpc.v1.cri".containerd]
    default_runtime_name = "runc"
    
    [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
      runtime_type = "io.containerd.runc.v2"
      
      [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
        SystemdCgroup = true

  [plugins."io.containerd.grpc.v1.cri".registry]
    [plugins."io.containerd.grpc.v1.cri".registry.mirrors]
      [plugins."io.containerd.grpc.v1.cri".registry.mirrors."docker.io"]
        endpoint = ["https://registry-1.docker.io"]

Tips and Tricks

• Use crictl for Kubernetes CRI operations (not ctr)
• Use nerdctl for Docker-compatible CLI with containerd backend
• Always specify namespace with -n k8s.io for Kubernetes containers
• Restart containerd after config changes: sudo systemctl restart containerd

Related Resources

• crictl Cheat Sheet
• Podman Cheat Sheet
• Buildah Cheat Sheet