Common Setup Steps for CKA K8s Cluster
Categories:
Disable Swap
Immediately turn off swap with the following command:
sudo swapoff -a
To ensure swap remains off after a reboot, modify the fstab file:
sudo sed -i 's|^/swap.img|#/swap.img|g' /etc/fstab
Load Modules
Load the necessary modules:
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF
Then, run the following commands:
sudo modprobe overlay
sudo modprobe br_netfilter
Sysctl Parameters
Set the required sysctl parameters that will persist across reboots:
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 the sysctl parameters without rebooting:
sudo sysctl --system
Install CRI-O Runtime
Update the package list and install required packages:
sudo apt-get update -y
sudo apt-get install -y \
software-properties-common \
curl \
apt-transport-https \
ca-certificates
Add the CRI-O package repository:
curl -fsSL https://pkgs.k8s.io/addons:/cri-o:/prerelease:/main/deb/Release.key |
gpg --dearmor -o /etc/apt/keyrings/cri-o-apt-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/cri-o-apt-keyring.gpg]
https://pkgs.k8s.io/addons:/cri-o:/prerelease:/main/deb/ /" |
tee /etc/apt/sources.list.d/cri-o.list
Next, install CRI-O:
sudo apt-get update -y
sudo apt-get install -y cri-o
Enable and start the CRI-O service:
sudo systemctl daemon-reload
sudo systemctl enable crio --now
sudo systemctl start crio.service
Install Kubeadm
Add the Kubernetes package signing key:
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key |
gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
Add the Kubernetes repository:
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg]
https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /" |
sudo tee /etc/apt/sources.list.d/kubernetes.list
Update package lists and install the required Kubernetes components:
sudo apt update
sudo apt install -y kubeadm=1.28.15-1.1 \
kubelet=1.28.15-1.1 \
kubectl=1.28.15-1.1
Disable Auto-Update Services
Prevent the auto-update of specific packages:
sudo apt-mark hold kubelet kubectl kubeadm cri-o
Final Configuration
Install jq for processing JSON data:
sudo apt install jq -y
Retrieve the local IP address for configuration:
local_ip="$(ip --json a s | jq -r '.[] | if .ifname == "eth1" then .addr_info[] | if .family == "inet" then .local else empty end else empty end')"
Create or modify the Kubelet configuration:
cat > /etc/default/kubelet << EOF
KUBELET_EXTRA_ARGS=--node-ip=$local_ip
${ENVIRONMENT}
EOF
Finally, restart the Kubelet service:
sudo systemctl restart kubelet
sudo systemctl status kubelet
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