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Join a node

This document outlines the procedures for joining a node into an OpenYurt cluster. There are two primary methods depending on the node's initial state:

1. Joining a New Node from Scratch​

This method is for nodes that are not yet part of any Kubernetes cluster. The yurtadm join command streamlines this process by installing necessary components and connecting the node to the OpenYurt cluster.

Prerequisites​

Before joining, ensure the following conditions are met on the node:

  • A container runtime (like containerd or Docker) is installed and running.
  • The swap partition is turned off.
  • The node has network connectivity to the Kubernetes API server.

1.1 Using yurtadm join​

The yurtadm join command handles the installation of kubeadm, kubelet, and kube-proxy, and then joins the node to the cluster.

To join an edge node:

  • yurtadm binary can be downloaded from the OpenYurt Releases page.
  • how to compile yurtadm binary, please refer to the link here
yurtadm join <apiserver-address>:6443 --token=<apiserver-token> --node-type=edge --discovery-token-unsafe-skip-ca-verification --v=5

If the edge node uses containerd as its runtime, you must specify the --cri-socket parameter:

yurtadm join <apiserver-address>:6443 --token=<token> --node-type=edge --discovery-token-unsafe-skip-ca-verification --cri-socket=/run/containerd/containerd.sock --v=5

To join a cloud node:

yurtadm join <apiserver-address>:6443 --token=<token> --node-type=cloud --discovery-token-unsafe-skip-ca-verification --v=5

Parameter Explanation:

  • <apiserver-address>:6443: The address of the apiserver.
  • --token: The bootstrap token for authenticating with the cluster. Refer to the Kubernetes documentation on how to generate a token.
  • --node-type: openyurt node type, which can be cloud or edge.

1.2 Component and CNI Handling​

yurtadm join will automatically handle component installation.

  • Kubernetes Components: It installs kubelet, kubeadm, etc. You can pre-place these binaries in your $PATH to use a specific version, but yurtadm will verify that their major and minor versions match the cluster's Kubernetes version.
  • CNI Binaries: The join process pulls specially modified CNI binaries (e.g., for Flannel) to suit edge environments. If you have prepared your own CNI binaries, place them under /opt/cni/bin and use the --reuse-cni-bin=true flag with the yurtadm join command.