Step-by-Step Guide to Building a Kubernetes v1.22.1 Cluster with containerd Using kubeadm

Environment Preparation

Three CentOS 7.6 nodes (kernel 3.10.0-1062.4.1.el7.x86_64) are used. Add host entries for master , node1 , and node2 to /etc/hosts and set proper DNS-compliant hostnames using hostnamectl set-hostname . Disable the firewall and SELinux, load the br_netfilter module, and create /etc/sysctl.d/k8s.conf with:

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1

Apply the settings with sysctl -p /etc/sysctl.d/k8s.conf . Install ipvs modules via a script placed in /etc/sysconfig/modules/ipvs.modules , then verify with lsmod | grep -e ip_vs -e nf_conntrack_ipv4 . Install ipset and ipvsadm for IPVS management, synchronize time with chrony , and disable swap (both runtime and in /etc/fstab ) while setting vm.swappiness=0 .

Install containerd

Download the latest cri-containerd-cni-1.5.5-linux-amd64.tar.gz release, extract it to the root filesystem, and add /usr/local/bin and /usr/local/sbin to PATH in ~/.bashrc :

export PATH=$PATH:/usr/local/bin:/usr/local/sbin
source ~/.bashrc

Generate the default configuration:

mkdir -p /etc/containerd
containerd config default > /etc/containerd/config.toml

Set the cgroup driver to systemd by editing the plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options section and adding SystemdCgroup = true . Configure registry mirrors (e.g., Aliyun) in the registry.mirrors block.

Enable and start containerd with systemd:

systemctl daemon-reload
systemctl enable containerd --now

Verify the installation with ctr version and crictl version .

Install kubeadm, kubelet, and kubectl

Add the Kubernetes yum repository (Google or Aliyun mirror) and install version 1.22.1 :

# Google repo
cat <
/etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
        https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

# Install packages
yum makecache fast
yum install -y kubelet-1.22.1 kubeadm-1.22.1 kubectl-1.22.1 --disableexcludes=kubernetes
systemctl enable --now kubelet

Initialize the Cluster

Generate a default kubeadm configuration and customize it (image repository, pod subnet 10.244.0.0/16 , kube-proxy mode ipvs , etc.):

kubeadm config print init-defaults --component-configs KubeletConfiguration > kubeadm.yaml
# Edit kubeadm.yaml to set imageRepository, podSubnet, and other options as needed.

Pull required images in advance (handle the missing coredns image by pulling manually and retagging):

kubeadm config images pull --config kubeadm.yaml
# If coredns fails, pull manually:
ctr -n k8s.io i pull docker.io/coredns/coredns:1.8.4
ctr -n k8s.io i tag docker.io/coredns/coredns:1.8.4 registry.aliyuncs.com/k8sxio/coredns:v1.8.4

Initialize the control plane:

kubeadm init --config kubeadm.yaml

Copy the admin kubeconfig for the regular user:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Verify the master node:

kubectl get nodes

Add Worker Nodes

Copy $HOME/.kube/config to each worker, install kubeadm/kubelet/kubectl, and run the join command printed by kubeadm init . If the command is lost, retrieve it with:

kubeadm token create --print-join-command

Install Flannel CNI Plugin

Download the Flannel manifest, adjust the interface name if the node has multiple NICs, and apply:

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# Edit the DaemonSet to set "--iface=eth0" if needed.
kubectl apply -f kube-flannel.yml

After a short wait, verify the pods in kube-system are running and the node status changes to Ready .

Deploy Kubernetes Dashboard

Download the recommended Dashboard manifest (v2.3.1), change the Service type to NodePort , and apply:

wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.3.1/aio/deploy/recommended.yaml
# Edit the Service to add "type: NodePort"
kubectl apply -f recommended.yaml

Get the NodePort (e.g., 31050 ) and access the Dashboard via https:// :31050 . Create a ServiceAccount with cluster‑admin rights:

cat <
admin.yaml
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: admin
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
  name: admin
  namespace: kubernetes-dashboard
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin
  namespace: kubernetes-dashboard
EOF
kubectl apply -f admin.yaml

Retrieve the token and use it to log in:

kubectl -n kubernetes-dashboard get secret | grep admin-token
kubectl -n kubernetes-dashboard get secret admin-token-xxxxx -o jsonpath={.data.token} | base64 -d

Cleanup

If you need to reset the cluster, run:

kubeadm reset
ifconfig cni0 down && ip link delete cni0
ifconfig flannel.1 down && ip link delete flannel.1
rm -rf /var/lib/cni/

After completing these steps you will have a functional Kubernetes v1.22.1 cluster using containerd, with CoreDNS, IPVS kube‑proxy, Flannel networking, and the Dashboard UI.