Initializing Kubernetes Cluster

To initialize the Kubernetes cluster, execute the operations on the first main node:

Start the initialization command under the root user:

kubeadm init

Finish the root user session:

exit

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

Get the command for cluster connection. To do this, execute the command under the name of the selected user:

kubeadm create token --print-join-command

The example of response:

kubeadm join {<main node IP address>}:6443 --token XXXXXXXXXXXX \
--discovery-token-ca-cert-hash sha256:YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

IMPORTANT. Execute the obtained command on each cluster node under the root user.

After executing the operations, the Kubernetes cluster is initialized on the main node. Next, set up the intra-cluster network.

Setting Up Intra-Cluster Network

Intra-cluster network (CNI) is set up using the cilium utility on the first main node.

To set up intra-cluster network:

Get the list of cluster nodes:

kubectl get nodes

After this the list of cluster nodes with the NotReady status is obtained. Status depends on intra-cluster network settings.

Add a link to the cilium utility to the Helm repository and install the utility:

helm repo add cilium https://helm.cilium.io/
helm install cilium cilium/cilium --version 1.15.4 --namespace kube-system

Install the cilium client:

CILIUM_CLI_VERSION=$(curl -s https://raw.githubusercontent.com/cilium/cilium-cli/main/stable.txt)
CLI_ARCH=amd64
if [ "$(uname -m)" = "aarch64" ]; then CLI_ARCH=arm64; fi
curl -L --fail --remote-name-all https://github.com/cilium/cilium-cli/releases/download/${CILIUM_CLI_VERSION}/cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}
sha256sum --check cilium-linux-${CLI_ARCH}.tar.gz.sha256sum
sudo tar xzvfC cilium-linux-${CLI_ARCH}.tar.gz /usr/local/bin
rm cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}

Check status of the intra-cluster network:

cilium status --wait

Cluster nodes should change their status to Ready.

Start intra-cluster network test and wait until it is finished:

cilium connectivity test

The example of response:

69/69 tests successful (0 warnings)

If there are no errors and warnings, the network and cluster are set up correctly.

Get the list of cluster nodes again:

kubectl get nodes

After this the list of cluster nodes with the Ready status is obtained.

Next, set up the Kubernetes external network.