Yaki

Yaki - Another Kubernetes Installer leads the installation of a barebone Kubernetes cluster in a simplified and automated way and it is entirely independent of the infrastructure you’re running on.

It leverages on kubeadm, one of the official installation tools from Kubernetes community.

New to Kubernetes? The official Kubernetes docs already have some great tutorials outlining the basics here.

Getting Started

This readme will help you quickly launch a cluster with default options.

Requirements

Make sure your environment fulfills following requirements:

• A set of compatible Linux machines with systemd. We widely useing yaki on Ubuntu 20.04 and Ubuntu 22.04.
• Full network connectivity between all machines in the cluster (public or private network is fine).
• Unique hostname, MAC address, and IP address for every machine.
• Swap configuration. The default behavior of a kubeadm install was to fail to start if swap memory was detected.
• Must be run as the root user or through sudo.

Prerequisites

The script expects some tools to be installed on your machines. It will fail if they are not found: conntrack, socat, wget.

Most of them should be already available in a bare Ubuntu installation.

Initialize Cluster

Choose a "seed" machine hosting the control plane of the Kubernetes cluster, login to the machine and run:

curl -sfL https://goyaki.clastix.io | sudo bash -s init

the script will setup the machine, install the container runtime containerd, among other required tools, install the kubelet, kubeadm, kubectl binaries and setup the control plane.

Once the initialization completes, take note of the output:

JOIN_URL=<join-url>
JOIN_TOKEN=<token>
JOIN_TOKEN_CERT_KEY=<certificate-key>
JOIN_TOKEN_CACERT_HASH=sha256:<discovery-token-ca-cert-hash>

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

If you are adding additional control plane nodes, you must have an odd number in total. An odd number is needed to maintain quorum. See Advanced Usage for more details.

Join Workers

To join other machines as worker nodes, you have to run yaki on each machine passing the join command along with some variables. Login to the machine you want to turn in a worker node and run:

curl -sfL https://goyaki.clastix.io | sudo JOIN_URL=<join-url> JOIN_TOKEN=<token> JOIN_TOKEN_CACERT_HASH=sha256:<hash> bash -s join

the script will setup the machine, install the container runtime containerd, among other required tools, install the kubelet, kubeadm, kubectl binaries and join the machine to the control plane node.

Working with the Cluster

Once joined all the desired worker nodes, back to the machine hosting the Control Plane and check the cluster has formed:

kubectl get nodes

Cluster nodes are still in a NotReady state because of the missing CNI add-on.

Please refer to the Installing Addons page for a non-exhaustive list of networking addons supported by Kubernetes. You can install a Pod network add-on with the following command:

kubectl apply -f <add-on.yaml>

Documentation

The yaki tool is self-documented:

$ curl -sfL https://goyaki.clastix.io | sudo bash -s help
Usage:

  ENV=... yaki.bash <init|join|reset|help>
    or
  curl -sfL https://goyaki.clastix.io | ENV=... bash -s <init|join|reset|help>

Commands:

  init: Deploy the first control-plane node of the Kubernetes cluster
    - This command initializes the Kubernetes control-plane on the first node.
    - Requires: JOIN_URL (optional), KUBEADM_CONFIG (optional), ADVERTISE_ADDRESS(optional), BIND_PORT (optional), KUBERNETES_VERSION (optional)
    - Example: KUBERNETES_VERSION=v1.30.5 yaki init
    - Example: JOIN_URL=<control-plane-endpoint>:<port> KUBERNETES_VERSION=v1.30.5 yaki init
    - Example: KUBEADM_CONFIG=kubeadm-config.yaml KUBERNETES_VERSION=v1.30.5 yaki init

  join: Join a control plane node to the cluster
    - This command joins the node as control plane to an existing Kubernetes cluster.
    - It also installs all necessary prerequisites, container runtime, CNI plugins, and Kubernetes binaries.
    - Requires: JOIN_URL, JOIN_TOKEN, JOIN_TOKEN_CACERT_HASH, JOIN_ASCP, KUBERNETES_VERSION (optional)
    - Example: JOIN_URL=<control-plane-endpoint>:<port> JOIN_TOKEN=<token> JOIN_TOKEN_CERT_KEY=<key> JOIN_TOKEN_CACERT_HASH=sha256:<hash> JOIN_ASCP=1 KUBERNETES_VERSION=v1.30.5 yaki join

  join: Join a node to the cluster
    - This command joins the node to an existing Kubernetes cluster.
    - Requires: JOIN_URL, JOIN_TOKEN, JOIN_TOKEN_CACERT_HASH, KUBERNETES_VERSION (optional)
    - Example: JOIN_URL=<control-plane-endpoint>:<port> JOIN_TOKEN=<token> JOIN_TOKEN_CACERT_HASH=sha256:<hash> KUBERNETES_VERSION=v1.30.5 yaki join

  reset: Reset the node
    - This command removes all Kubernetes components and configurations from the node.
    - Example: yaki reset

  help: Print this help
    - Displays this help message.
    - Example: yaki help

Environment variables:

  +-------------------------+-------------------------------------------------------------+------------+
  | Variable                | Description                                                 | Default    |
  +-------------------------+-------------------------------------------------------------+------------+
  | KUBERNETES_VERSION      | Version of kubernetes to install.                           | v1.30.5    |
  | CONTAINERD_VERSION      | Version of container runtime containerd.                    | see matrix |
  | RUNC_VERSION            | Version of runc to install.                                 | see matrix |
  | CNI_VERSION             | Version of CNI plugins to install.                          | see matrix |
  | CRICTL_VERSION          | Version of crictl to install.                               | see matrix |
  | KUBEADM_CONFIG          | Path to the kubeadm config file to use.                     | Not set    |
  | ADVERTISE_ADDRESS       | Address to advertise for the api-server.                    | 0.0.0.0    |
  | BIND_PORT               | Port to use for the api-server.                             | 6443       |
  | JOIN_TOKEN              | Token to join the control-plane.                            | Not set    |
  | JOIN_TOKEN_CACERT_HASH  | Token Certificate Authority hash to join the control-plane. | Not set    |
  | JOIN_TOKEN_CERT_KEY     | Token Certificate Key to join the control-plane.            | Not set    |
  | JOIN_URL                | URL to join the control-plane.                              | Not set    |
  | JOIN_ASCP               | Switch to join either as control plane or worker.           | 0          |
  | DEBUG                   | Set to 1 for more verbosity during script execution.        | 0          |
  +-------------------------+-------------------------------------------------------------+------------+

Advanced Usage

A guide with more advanced usage of yaki can be found here.

Contributions

This is an open-source tool. If you find errors, typos, or just want to improve yaki, feel free to open a pull request. Contributions are always welcome!