Join Nodes

    Users can join cloud nodes and edge nodes to the OpenYurt cluster using Yurtadm join. Note that when joining a node, the runtime needs to be installed on the node and the swap partition is turned off.

    Execute the following command to join the edge node to cluster:

    Execute the following command to join the cloud node to cluster:

    When the runtime of the edge node is containerd, the cri-socket parameter needs to be configured. For example, change the command above of joining the edge node to:

    1. $ _output/local/bin/linux/amd64/yurtadm join 1.2.3.4:6443 --token=zffaj3.a5vjzf09qn9ft3gt --node-type=edge --discovery-token-unsafe-skip-ca-verification --cri-socket=/run/containerd/containerd.sock --v=5
    • how to compile yurtadm binary, please refer to the link here

    Explanation of parameters:

    • 1.2.3.4:6443: The address of apiserver
    • --token：bootstrap token
    • --node-type：openyurt node type，can be cloud or edge

    The process of yurtadm join` will automatically install the following k8s components:

    • kubeadm
    • kubectl
    • kubelet

    1.2 yurtadm reset

    In master：

    1. kubectl drain {NodeName} --delete-local-data --force --ignore-daemonsets
    2. kubectl delete node {NodeName}

    In joined node:

    1. execute yurtadm reset
    1. yurtadm reset
    1. delete /etc/cni/net.d dir：

    2. Install OpenYurt node components

    You should only install node components of OpenYurt on nodes that already have been joined in the Kubernetes cluster.

    OpenYurt distinguish cloud nodes and edge nodes through the node label openyurt.io/is-edge-worker. From this, it makes the decision that whether to evict Pods on this node. Assume we have a node named us-west-1.192.168.0.88 which is an edge node.

    1. $ kubectl label node us-west-1.192.168.0.88 openyurt.io/is-edge-worker=true

    To further activate the node autonomous mode, we add an annotation to this edge node:

    1. $ kubectl annotate node us-west-1.192.168.0.88 node.beta.openyurt.io/autonomy=true
    2. node/us-west-1.192.168.0.88 annotated
    1. $ cat <<EOF | kubectl apply -f -
    2. apiVersion: apps.openyurt.io/v1alpha1
    3. kind: NodePool
    4. metadata:
    5.   name: worker
    6. spec:
    7.   type: Edge
    8. EOF
    9. $ kubectl label node us-west-1.192.168.0.87 apps.openyurt.io/desired-nodepool=worker

    2.2 Setup Yurthub

    Before proceeding, we need to prepare the following items:

    1. Get the apiserver’s address (i.e., ip:port) and a , which will be used to replace the placeholder in the template file config/setup/yurthub.yaml.

    In the following command, we assume that the address of the apiserver is 1.2.3.4:5678 and bootstrap token is 07401b.f395accd246ae52d

    1. sed 's|__kubernetes_master_address__|1.2.3.4:5678|;
    3. scp -i <yourt-ssh-identity-file> /tmp/yurthub-ack.yaml root@us-west-1.192.168.0.88:/etc/kubernetes/manifests

    and the Yurthub will be ready in minutes.

    we need to reset the kubelet service to let it access the apiserver through the yurthub (The following steps assume that we have logged on to the edge node as the root user). As kubelet will connect to the Yurthub through HTTP, so we create a new kubeconfig file for the kubelet service.

    In order for let kubelet to use the new kubeconfig, we edit the drop-in file of the kubelet service (i.e., /etc/systemd/system/kubelet.service.d/10-kubeadm.conf or /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf for CentOS)

    1. sed -i "s|KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=\/etc\/kubernetes\/bootstrap-kubelet.conf\ --kubeconfig=\/etc\/kubernetes\/kubelet.conf|KUBELET_KUBECONFIG_ARGS=--kubeconfig=\/var\/lib\/openyurt\/kubelet.conf|g" \
    2.     /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

    then, we restart the kubelet service

    1. # assume we are logged in to the edge node already
    2. $ systemctl daemon-reload && systemctl restart kubelet
    1. $ kubectl get nodes
    2. NAME                     STATUS   ROLES    AGE     VERSION
    3. us-west-1.192.168.0.87   Ready    <none>   3d23h   v1.20.11
    4. us-west-1.192.168.0.88   Ready    <none>   3d23h   v1.20.11

    2.4 Restart Pods

    After Yurthub installation and kubelet restart, all pods on this edge node should be recreated in order to make sure pods access kube-apiserver through Yurthub. Before performing this operation, confirm the impact on the production environment.

    1. $ kubectl get pod -A -o wide | grep us-west-1.192.168.0.88
    2. kube-system   yurt-hub-us-west-1.192.168.0.88           1/1     Running   0          19d     172.16.0.32    us-west-1.192.168.0.88   <none>           <none>
    3. kube-system   coredns-qq6dk                             1/1     Running   0          19d     10.148.2.197   us-west-1.192.168.0.88   <none>           <none>
    4. kube-system   kube-flannel-ds-j698r                     1/1     Running   0          19d     172.16.0.32    us-west-1.192.168.0.88   <none>           <none>
    5. kube-system   kube-proxy-f5qvr                          1/1     Running   0          19d     172.16.0.32    us-west-1.192.168.0.88   <none>           <none>
    8. $ kubectl -n kube-system delete pod coredns-qq6dk kube-flannel-ds-j698r kube-proxy-f5qvr