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Vanilla Kubernetes Installation

Kubernetes is composed of master(s) and workers. The instructions and script 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 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 later. For other Linux-based operating systems see Kubernetes documentation](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/){target=_blank}.
  • The script must be run with ROOT privileges.
  • Inbound ports 6443,443,8080 must be allowed.
  • The script supports Kubernetes 1.24 or later.

Install Kubernetes

Install Kubernetes Master

  • Get the script by running:
wget https://raw.githubusercontent.com/run-ai/docs/v2.16/install/kube-install.sh
  • Run the script with ROOT privileges: sudo ./kube-install.sh
  • When prompted, select the option to install Kubernetes master.
  • Select the Kubernetes version you want or press Enter for the default script version.
  • Select the CNI (networking) version or press Enter for the default.

When the script finishes, it will prompt a join command_ to be run on all workers. Save the command for later use.

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.

Test that Kubernetes is up by running: 

kubectl get nodes
Verify that the master node is ready

Install Kubernetes Workers

On each designated worker node:

  • Get the script by running:
wget https://raw.githubusercontent.com/run-ai/docs/v2.16/install/kube-install.sh
  • Run the script with ROOT privileges: sudo ./kube-install.sh
  • When prompted, select the option to install Kubernetes worker.
  • Select the Kubernetes version you want or press Enter for the default script version. The version should be the same as the one selected for the Kubernetes master.

When the script finishes, run the join command saved above.

To test that the worker has successfully joined, on the master node run: 

kubectl get nodes
Verify that the new worker node is showing and ready (may take a couple of seconds).

Avoiding Accidental Upgrades

To avoid an accidental upgrade of Kubernetes binaries during Linux upgrades, it is recommended to hold the version. Run the following on all nodes:

sudo apt-mark hold kubeadm kubelet kubectl

Next Steps

The administrative Kubernetes profile can be found in the master node under the .kube folder.

Reset Nodes

The same script also contains an option to completely remove Kubernetes from nodes (master or workers). To use, run:

  • Get the script by running:
wget https://raw.githubusercontent.com/run-ai/docs/v2.16/install/kube-install.sh
  • Run the script with ROOT privileges: sudo ./kube-install.sh
  • When prompted, select the option to reset/delete kubernetes.
  • Select yes when prompted to reset the cluster and remove Kubernetes packages.