Setup k8s worker node on Ubuntu 20.04
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What I did
Install k8s worker node on Ubuntu 20.04 VM server. Most parts are similar to master node installation instruction.
Environments
- Ubuntu 20.04
Requirement
- 2 CPU required.
sudo swapoff -a
Install Docker
sudo apt update
sudo apt install -y docker.io
sudo systemctl enable docker
Set up worker node
Network configuration before installing
Change kernel parameters and open ports for master node.
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system
sudo modprobe br_netfilter
sudo ufw allow 8080/tcp
sudo ufw allow 10250/tcp
sudo ufw allow 30000:32767/tcp
Install k8s
I use kubenetes-xenial in focal, but as of 2020/06/01 I can’t find any issue.
sudo apt update && sudo apt install -y apt-transport-https curl
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF
sudo apt update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl
Configure worker node
Get tokens from master node
$ kubeadm token list
TOKEN TTL EXPIRES USAGES DESCRIPTION EXTRA GROUPS
e9h7ct.rorktp6zc2yz5us3 15h 2020-06-01T03:12:33Z authentication,signing The default bootstrap token generated by 'kubeadm init'. system:bootstrappers:kubeadm:default-node-token
Sometimes, there is not token because it has TTL. If then, create a token by the command below.
kubeadm token create
You need also and a hash value.
openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
Join to node
With tokens you got above, join to the master node.
sudo kubeadm join --token {{ your_token}} --discovery-token-ca-cert-hash sha256:{{ cert_hash }} {{ k8s_masternode_IP }}:6443
{{ k8s_masternode_IP }} SHOULD be and IP (hostname doesn’t work in my case.)
Done!!
Additional
Add a label ROELS to the worker node.
k8smaster:~$ kubectl get node
NAME STATUS ROLES AGE VERSION
k8smaster Ready master 4d v1.18.3
k8sworker Ready <none> 2d23h v1.18.3
A node role is just a label with the format node-role.kubernetes.io/<role>
kubectl label node k8sworker node-role.kubernetes.io/worker=worker
Tips: delete label
kubectl label node k8sworker node-role.kubernetes.io/worker-