Create an Kubernetes Multi-Node Cluster of AWS Free Tier with CRI-O as Container Engine

Finally I am able to complete the article on creating multi-node cluster on AWS Free tier. i.e. using a t2.micro. Hope this article is useful. You can connect me on LinkedIn if any help needed.

Launched VMs from the aws cloud

• ubuntu 22.04 instance with t2.micro

The article will compose of following sections
1. Master Node Configuration
2. Worker Node configuration

1. Master Node Configuration

Let’s Setup cri-o engine first

Update the packages and install the following dependencies:

$ sudo apt update
$ sudo apt install apt-transport-https ca-certificates curl gnupg2 software-properties-common -y

Now let’s configure the CRI-O repository:

## Define the variables below 
$ export OS=xUbuntu_22.04
$ export CRIO_VERSION=1.24

# Configure the repositories 
$ echo "deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/ /"| sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
$ echo "deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$CRIO_VERSION/$OS/ /"|sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$CRIO_VERSION.list

# configure the GPG keys 
$ curl -L https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:$CRIO_VERSION/$OS/Release.key | sudo apt-key add -
$ curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/Release.key | sudo apt-key add -
$ sudo apt update

#Finally install the cri-o docker engine
$ sudo apt install cri-o cri-o-runc -y
$ sudo systemctl start crio
$ sudo systemctl enable crio
$ sudo systemctl status crio

Now let’s setup the CNI Plugings for the CRI-O

$ sudo apt install containernetworking-plugins -y
$ vi /etc/crio/crio.conf
$ sudo systemctl restart crio

# Optional (If you require crictl command)
sudo apt install -y cri-tools

Networking Configuration:

As a root user run the following commands

$ cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

$ modprobe overlay
$ modprobe br_netfilter

$ cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

# Apply sysctl params without reboot
sudo sysctl --system

Finally, Configuring the Kubernetes Repository

$ sudo apt-get install -y apt-transport-https ca-certificates curl gpg
$ curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/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:/v1.29/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
$ sudo apt-get update
$ sudo apt-get install -y kubelet kubeadm kubectl
$ sudo apt-mark hold kubelet kubeadm kubectl
$ systemctl start  kubelet
$ systemctl enable --now kubelet

Initiate the cluster:

$ kubeadm init — pod-network-cidr=10.244.0.0/16 — ignore-preflight-errors=NumCPU — ignore-preflight-errors=Mem — cri-socket=unix:///var/run/crio/crio.sock

it would take some time, then configure the kubectl command:

and note the kubeadm join command that you will get at the end

$ 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 kubectl command is working

root@ip-172-31-39-227:~# kubectl get nodes 
NAME               STATUS   ROLES           AGE   VERSION
ip-172-31-39-227   Ready    control-plane   64s   v1.29.0

root@ip-172-31-39-227:~# kubectl get pods -A
NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE
kube-system   coredns-76f75df574-lsvkc                   1/1     Running   0          55s
kube-system   coredns-76f75df574-rxw6f                   1/1     Running   0          55s
kube-system   etcd-ip-172-31-39-227                      1/1     Running   0          71s
kube-system   kube-apiserver-ip-172-31-39-227            1/1     Running   0          68s
kube-system   kube-controller-manager-ip-172-31-39-227   1/1     Running   0          69s
kube-system   kube-proxy-hf659                           1/1     Running   0          55s
kube-system   kube-scheduler-ip-172-31-39-227            1/1     Running   0          68s

2. Configuring the worker node

Configure the cri-o engine

$ sudo apt update
$ sudo apt install apt-transport-https ca-certificates curl gnupg2 software-properties-common -y

## Define the variables below 
$ export OS=xUbuntu_22.04
$ export CRIO_VERSION=1.24

# Configure the repositories 
$ echo "deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/ /"| sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
$ echo "deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$CRIO_VERSION/$OS/ /"|sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$CRIO_VERSION.list

# configure the GPG keys 
$ curl -L https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:$CRIO_VERSION/$OS/Release.key | sudo apt-key add -
$ curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/Release.key | sudo apt-key add -
$ sudo apt update

#Finally install the cri-o docker engine
$ sudo apt install cri-o cri-o-runc -y
$ sudo systemctl start crio
$ sudo systemctl enable crio
$ sudo systemctl status crio

Configure networking, Run the below commands:

$ cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

$ modprobe overlay
$ modprobe br_netfilter

$ cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

# Apply sysctl params without reboot
sudo sysctl --system

Configure kubelet and kubeadm (generally we don’t require kubectl on the worker nodes)

$ sudo apt-get install -y apt-transport-https ca-certificates curl gpg
$ curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/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:/v1.29/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
$ sudo apt-get update
$ sudo apt-get install -y kubelet kubeadm
$ sudo apt-mark hold kubelet kubeadm
$ systemctl start  kubelet
$ systemctl enable --now kubelet

We are now ready to join the cluster, hope you remember the join command

$ kubeadm join 172.31.39.227:6443 — token h6gja6.712g23rje3wdm7he — discovery-token-ca-cert-hash sha256:63466b11aeec4028e76efd3542de5fad2274bb5da033ae8f55940fad166bdfda — ignore-preflight-errors=NumCPU — ignore-preflight-errors=Mem — cri-socket=unix:///var/run/crio/crio.sock

Now we can see that there are two nodes on our cluster.

root@ip-172-31-39-227:~# kubectl get nodes
NAME               STATUS   ROLES           AGE   VERSION
ip-172-31-38-126   Ready    <none>          32s   v1.29.0
ip-172-31-39-227   Ready    control-plane   10m   v1.29.0

Finally we are done with configuring the multi-node k8s. More nodes can be added by joining the new nodes !!

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