This document will describe SuperEdge's new ability: Kins, which can promote the standard edge nodes pool NodeUnit to an independent K3s cluster by just one click. Then this edge nodes pool can be disconnected from the cloud control plane and run totally offline for a long time. During the offline time, it can be operated as a standard K3s cluster for independent operation and maintenance. If there is a need for operation or upgrade in the later stage, the edge node pool can reconnect to the cloud control plane to achieve the goal. This feature improves the shortcomings of the previous NodeUnit which can't be operated offline.
In the cloud native && edge computing scenario, most users have two basic scene demands for the edge side
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Manage the independent edge node through K8s control plane on cloud side
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The platform manages the independent K8s cluster on the edge side, also known as edge cloud
SuperEdge frameworks previously focused on the scenario of processing management of edge node. Although we provide similar NodeUnit capabilities and have certain edge regional autonomy capabilities, they cannot achieve complete offline independence and autonomy on the edge side, due to the architecture. It is limited in many scenarios such as intelligent industries. After communicating with many industry customers, we found that most industry customers are more likely to accept the edge side lightweight independent cluster, and these customers basically choose K3s as the solution of edge side products.
However, at the present time, this scheme can only be deployed and implemented in a way similar to privatization delivery. In the edge computing scenaro of multi regions/ few nodes/ scattered distribution, "cloud" + "edge cloud" project will encounter the difficulty of delivery and high cost.
Therefore, in response to this scenario, SuperEdge proposes this Kins architecture. Users can join the edge nodes to the cloud K8s control plane, and simply operate the governance level of NodeUnit in the cloud, then SuperEdge will provision K3s cluster on the edge nodes. The K3s cluster can be remotely controlled from the cloud side, and it also can be completely offline as a standalone cluster. It can be connected to the cloud control plane as needed, and remotely upgraded through cloud-edge tunnel for remote operation and maintance, greatly reducing delivery and maintance costs.
Through this new feature, it's possilbe to cover the majority of the basic requirements in edge computing scenarios.
The basic principle is show in the figure above:
Multiple nodes on the edge side can be grouped as NodeUnit. Through relevant operations on the cloud, SuperEdge will pull up the corresponding master and agent componentes of K3s to form a single master or 3 master K3s cluster. This edge K3s cluster can be accessed from the cloud through tunnel, and can also be directly accessed on the edge nodes.
Please create a SuperEdge cluster with the latest version of Edgeadm, and join the edge nodes as below:
Please use the standard NodeUnit CRD Yaml to create the edge nodes pool, as below:
apiVersion: site.superedge.io/v1alpha2
kind: NodeUnit
metadata:
name: test
spec:
autonomyLevel: L3
nodes:
- edge1
- edge2
- edge3
type: edge
unschedulable: falseUsers only need to focus on these 2 varibles in configuration:
autonomyLevel: This is the key point of Kins. L3 refert to the standard NodeUnit, and L4 refer to the single master K3s cluster, L5 means the 3 master K3s cluster
nodes: refer to the list of nodes on the edge node pool
After creating the NodeUnit, you can review the corresponding information:
Modify the test NodeUnit's autonomyLevel to L4, as below:
Observe the corresponding pods has been activated:
Annotations:
test-server-kins: the pod referring to master node of K3s
test-agnet-kins: the pod referring to worker node of K3s
test-cri-kins: components of cri proxy on the nodes
Now we can access this K3s cluster from both cloud and edge sides, as follows
The kubeconfig of edge cluster is stored in the configmap of kins-system namespace. In this example, it's test-cm-kins, test prefix is the name of the NodeUnit.
The kubeconfig file can be acquired by the following command:
kubectl get cm test-cm-kins -n kins-system -o=jsonpath='{.data.kubeconfig\.conf}'The kubeconfig file is show as follow:
Save the kubeconfig file to the desired edge node, for example, copy it to edge3 node and access the K3s cluster on this node:
In the future, this NodeUnit node pool can be completely disconnected from the cloud and operated totally offline.
If you want to access the edge K3s cluster from the cloud side, you need to use the proxy function of Tunnel, following the specific operations as follows:
- Obtain the svc information of
tunnel-cloudand get the proxy configuration:
Record the endpoint the
http-proxy, which can be accessed through the svc ip:8080. If you need to access the proxy out of the cluster, please use the master-ip:31469
- Confirm svc information of the edge K3s cluster
Get the K3s cluster's service address in the cluster, and you can use the service name or the service ip:
- Modify configuration of kubeconfig of chapter 4.1
apiVersion: v1
kind: Config
clusters:
- cluster:
insecure-skip-tls-verify: true
server: https://test-svc-kins.kins-system:443 #service name or service ip
proxy-url: http://127.0.0.1:31469 # use the tunnel-cloud 的 http-proxy on master node
name: default
contexts:
- context:
cluster: default
namespace: default
user: default
name: default
current-context: default
users:
- name: default
user:
token: rfj9s2bhpcs6fm9xxxxxxxxxxxxxxxxx- The result of accessing edge cluster from the cloud side:
Notice: If the autonomyLevel of NodeUnit is L4/L5, it can't be deleted directly. You need to dowgrade this NodeUnit to L3 before deleting. If the NodeUnit of L4/L5 is directly deleted, the cluster will block the deletion process and disply NodeUnit status as
Deleting
If you need to downgrade the K3s cluster to standard NodeUnit, you can manually modify the NodeUnit to L3. After modification, the SuperEdge cluster will recycle the edge side pods, and the edge K3s cluster will be destroyed.