Container Runtime

Read first

• The differences between Docker, containerd, CRI-O and runc

• Kubernetes Containerd Integration Goes GA

In summary, the container runtime used by nodes deployed in Google Kubernetes Engine (GKE) had moved from docker-based to containerd since Jun 2021 (v1.19.12-gke.2100). As a result, investigation methods (e.g. live response commands, mount container procedures) used for docker-based kubernetes clusters are no longer applicable for containerd-based clusters, and new / different methods have to be performed to obtain a similar outcome.

Identification of Container Runtime

# with kubectl
kubectl get nodes -o wide
:' sample output
# For Docker runtime
NAME         STATUS   VERSION             OS-IMAGE                             CONTAINER-RUNTIME
gke-node-1   Ready    v1.16.15-gke.6000   Container-Optimized OS from Google   docker://19.3.1
gke-node-2   Ready    v1.16.15-gke.6000   Container-Optimized OS from Google   docker://19.3.1
gke-node-3   Ready    v1.16.15-gke.6000   Container-Optimized OS from Google   docker://19.3.1
# For containerd runtime
NAME         STATUS   VERSION           OS-IMAGE                             CONTAINER-RUNTIME
gke-node-1   Ready    v1.19.6-gke.600   Container-Optimized OS from Google   containerd://1.4.1
gke-node-2   Ready    v1.19.6-gke.600   Container-Optimized OS from Google   containerd://1.4.1
gke-node-3   Ready    v1.19.6-gke.600   Container-Optimized OS from Google   containerd://1.4.1
'

# with gcp cli
gcloud container node-pools list --cluster <cluster-name> --format="table(name,version,config.imageType)"
:' sample output
NAME          NODE_VERSION     IMAGE_TYPE
default-pool  1.19.6-gke.600   UBUNTU_CONTAINERD
default-pool  1.17.17-gke.9100 COS
'

GKE Defaults

As of 30 Aug 2021 0250hrs (UTC)

Channel	Version	Default OS / Container Runtime	Date Added
Regular (default)	1.20.8-gke.2100 (default)	Container-Optimized OS with Containerd (cos_containerd)
	1.20.9-gke.700	Container-Optimized OS with Containerd (cos_containerd)
Rapid	1.20.8-gke.2100 (default)	Container-Optimized OS with Containerd (cos_containerd)
	1.20.9-gke.2100	Container-Optimized OS with Containerd (cos_containerd)
	1.21.3-gke.901	Container-Optimized OS with Containerd (cos_containerd)
	1.21.3-gke.1100	Container-Optimized OS with Containerd (cos_containerd)
	1.21.3-gke.2000	Container-Optimized OS with Containerd (cos_containerd)
Stable	1.19.12-gke.2100 (default)	Container-Optimized OS with Containerd (cos_containerd)
	1.18.20-gke.901	Container-Optimized OS with Docker (cos)
	1.18.20-gke.900	Container-Optimized OS with Docker (cos)
Static	1.20.8-gke.2100 (default)	Container-Optimized OS with Containerd (cos_containerd)
	1.17.17-gke.9100	Container-Optimized OS with Docker (cos)
	1.18.20-gke.900	Container-Optimized OS with Docker (cos)
	1.18.20-gke.901	Container-Optimized OS with Docker (cos)
	1.18.20-gke.2300	Container-Optimized OS with Docker (cos)
	1.18.20-gke.3000	Container-Optimized OS with Docker (cos)
	1.18.20-gke.3300	Container-Optimized OS with Docker (cos)
	1.18.20-gke.4100	Container-Optimized OS with Docker (cos)	17 Jun 2021
	1.19.12-gke.2100	Container-Optimized OS with Containerd (cos_containerd)
	1.19.13-gke.700	Container-Optimized OS with Containerd (cos_containerd)
	1.19.13-gke.1200	Container-Optimized OS with Containerd (cos_containerd)
	1.19.13-gke.1900	Container-Optimized OS with Containerd (cos_containerd)
	1.20.8-gke.900	Container-Optimized OS with Containerd (cos_containerd)
	1.20.9-gke.700	Container-Optimized OS with Containerd (cos_containerd)
	1.20.9-gke.1100	Container-Optimized OS with Containerd (cos_containerd)
	1.20.9-gke.2100	Container-Optimized OS with Containerd (cos_containerd)