In this lab you will install the Container Runtime Interface (CRI) on both worker nodes. CRI is a standard interface for the management of containers. Since v1.24 the use of dockershim has been fully deprecated and removed from the code base. containerd replaces docker as the container runtime for Kubernetes, and it requires support from CNI Plugins to configure container networks, and runc to actually do the job of running containers.
Reference: https://github.com/containerd/containerd/blob/main/docs/getting-started.md
The commands in this lab must be run on each worker instance: worker-1, and worker-2. Login to each controller instance using SSH Terminal.
Here we will install the container runtime containerd from the Ubuntu distribution, and kubectl plus the CNI tools from the Kubernetes distribution. Kubectl is required on worker-2 to initialize kubeconfig files for the worker-node auto registration.
You can perform this step with tmux
Set up the Kubernetes apt repository
{
KUBE_LATEST=$(curl -L -s https://dl.k8s.io/release/stable.txt | awk 'BEGIN { FS="." } { printf "%s.%s", $1, $2 }')
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/${KUBE_LATEST}/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:/${KUBE_LATEST}/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list
}Install containerd and CNI tools, first refreshing apt repos to get up to date versions.
{
sudo apt update
sudo apt install -y containerd kubernetes-cni kubectl ipvsadm ipset
}Set up containerd configuration to enable systemd Cgroups
{
sudo mkdir -p /etc/containerd
containerd config default | sed 's/SystemdCgroup = false/SystemdCgroup = true/' | sudo tee /etc/containerd/config.toml
}Now restart containerd to read the new configuration
sudo systemctl restart containerdPrev: Bootstrapping the Kubernetes Control Plane
Next: Bootstrapping the Kubernetes Worker Nodes