Native Kubeneretes Installation¶
Kubernetes is composed of master(s) and workers. The instructions below are for creating a bare-bones installation of a single master and several workers for testing purposes. For a more complex, production-grade, Kubernetes installation, use tools such as Kubespray https://kubespray.io/, Rancher Kubernetes Engine or review Kubernetes documentation to learn how to customize the native installation.
Prerequisites:¶
The script below assumes all machines have Ubuntu 18.04 or Ubuntu 20.04. For other Linux-based operating-systems see Kubernetes documentation.
Run on Master Node¶
If not yet installed, install docker by performing the instructions here. Specifically, you can use a convenience script provided in the document:
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
Restart the docker service:
sudo systemctl restart docker
Install Kubernetes master:
sudo sh -c 'cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF'
sudo apt-get update && sudo apt-get 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-get update
sudo apt-get install -y kubelet=1.20.5-00 kubeadm=1.20.5-00 kubectl=1.20.5-00
sudo swapoff -a
sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.20.5 --token-ttl 180h
The kubeadm init command above has emitted as output a kubeadm join command. Save it for joining the workers below.
Copy the Kubernetes configuration files which provides access to the cluster:
mkdir .kube
sudo cp -i /etc/kubernetes/admin.conf .kube/config
sudo chown $(id -u):$(id -g) .kube/config
Add Kubernetes networking:
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Test that Kubernetes is up and running:
kubectl get nodes
Run on Kubernetes Workers¶
If not yet installed, install docker by performing the instructions here: https://docs.docker.com/engine/install/ubuntu/. Specifically, you can use a convenience script provided in the document:
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
Restart the docker service:
sudo systemctl restart docker
On Worker Nodes with GPUs, install NVIDIA Docker and make it the default docker runtime as described here:
Install Kubernetes worker:
sudo sh -c 'cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF'
sudo apt-get update && sudo apt-get 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-get update
sudo apt-get install -y kubelet=1.20.5-00 kubeadm=1.20.5-00
sudo swapoff -a
Replace the following join command with the one saved from the init command above:
sudo kubeadm join 10.0.0.3:6443 --token <token> \
--discovery-token-ca-cert-hash sha256:<hash>
Note
The default token expires after 24 hours. If the token has expired, go to the master node and run sudo kubeadm token create --print-join-command. This will produce an up-to-date join command.
Return to the master node. Re-run kubectl get nodes and verify that the new node is ready.
Permanently disable swap on all nodes¶
- Edit the file /etc/fstab
- Comment out any swap entry if such exists