Note_Tech

All technological notes.

Project maintained by simonangel-fong Hosted on GitHub Pages — Theme by mattgraham

Kubernetes - kubeadm

Back

kubeadm

Imperative Command

CMD DESC
kubeadm version Prints the version of kubeadm
kubeadm init Initializes a control plane node
kubeadm join CLUSTER_IP initializes a new worker node and joins it to the existing cluster.
kubeadm upgrade plan VERSION Check which versions are available to upgrade
kubeadm upgrade apply VERSION Upgrade Kubernetes cluster to the specified version
kubeadm upgrade diff VERSION Show what differences would be applied.
kubeadm reset Performs a best effort revert of changes
CMD DESC
kubeadm config print init-defaults Print default init configuration for ‘kubeadm init’
kubeadm config print join-defaults Print default join configuration for ‘kubeadm join’
kubeadm config print reset-defaults Print default reset configuration for ‘kubeadm reset’
kubeadm config print upgrade-defaults Print default upgrade configuration for ‘kubeadm upgrade’
CMD DESC
kubeadm token create Create bootstrap tokens on the server
kubeadm token delete Delete bootstrap tokens on the server
kubeadm token generate Generate and print a bootstrap token, but do not create it on the server
kubeadm token list List bootstrap tokens on the server

Lab: Installing kubeadm, kubelet and kubectl

# confirm kernel
uname -r
# 6.14.0-37-generic

# confirm os
cat /etc/*-release
# DISTRIB_ID=Ubuntu
# DISTRIB_RELEASE=24.04
# DISTRIB_CODENAME=noble
# DISTRIB_DESCRIPTION="Ubuntu 24.04.3 LTS"
# PRETTY_NAME="Ubuntu 24.04.3 LTS"
# NAME="Ubuntu"
# VERSION_ID="24.04"
# VERSION="24.04.3 LTS (Noble Numbat)"
# VERSION_CODENAME=noble
# ID=ubuntu
# ID_LIKE=debian
# HOME_URL="https://www.ubuntu.com/"
# SUPPORT_URL="https://help.ubuntu.com/"
# BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
# PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
# UBUNTU_CODENAME=noble
# LOGO=ubuntu-logo

# turn off swap
sudo swapoff -a
sudo sed -i '/swap/ s/^/#/' /etc/fstab

# Update the apt package index and install packages
sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl gpg

# Download the public signing key
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.35/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

# Add the Kubernetes apt repository
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.35/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update the apt package index, install kubeadm
sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

# Enable the kubelet service
sudo systemctl enable --now kubelet

Lab: Init Controlplane

ip a
# 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
#     link/ether 00:0c:29:81:e1:09 brd ff:ff:ff:ff:ff:ff
#     altname enp2s1
#     inet 192.168.10.150/24 brd 192.168.10.255 scope global ens33
#        valid_lft forever preferred_lft forever

sudo kubeadm init --apiserver-advertise-address=192.168.10.150 --cri-socket=unix:///var/run/containerd/containerd.sock
# Your Kubernetes control-plane has initialized successfully!

# To start using your cluster, you need to run the following as a 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

# Alternatively, if you are the root user, you can run:

#   export KUBECONFIG=/etc/kubernetes/admin.conf

# You should now deploy a pod network to the cluster.
# Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
#   https://kubernetes.io/docs/concepts/cluster-administration/addons/

# Then you can join any number of worker nodes by running the following on each as root:

# kubeadm join 192.168.10.150:6443 --token j3pyeq.x6v6i \
#         --discovery-token-ca-cert-hash sha256:5e9d810d52a10

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

# confirm
kubectl get nodes
# NAME           STATUS     ROLES           AGE    VERSION
# controlplane   NotReady   control-plane   108s   v1.35.0