Cluster Net

Test Environment Access method

1# this machine is out of intel, please use the socks proxy:
2#                 proxy-prc.intel.com:1080
3# use this private key to access this the relay machine: 
4# first login to
5ssh -p 3302 airren@124.223.99.93  # passwd: 123-
6# next login to 
7ssh airren@node-1   # passwd:123-

PreRequisites

Kind

Create cluster

1# create cluster one node
2
3
4# create cluster multinode
5
6# create cluster with configuration

Delete cluster

1kind delete cluster --name=<clustername>

Setup mcs-api demo

Re-setup 4 cluster. This will create 4 K8s clusters by Kind. parent, child1,child2,child3.
```
1cd ~/clusternet/hack
2./local-running.sh
3
4export KUBECONFIG=${HOME}/.kube/clusternet.config
```
After that, you will see 4 clusters’ contexts.
Check Clusters status
Deploy application to child-clusters by kubectl clusternet.
- Change the cluster id in subscription.yaml to what you want to be deployed.
```
1cd ~/clusternet/examples/scheduling-with-mcs-api/scheduling
2vi subscription.yaml
```
- Deploy the applicaton(deployment, servcie, service-export) to the child-cluster
```
1cd ~/clusternet/examples/scheduling-with-mcs-api/
2k clusternet apply -f scheduling/
```
- Deploy the service import in the Parent-Cluster
```
1k apply -f service-import.yaml
```
Check the deploy result.

successfullycreated a service.and then, find the endpointslice bind with this service

The service port name shoule be same with the endpoint slice Name.

Archtecture

Clusternet is a lightweight addon that consists of three components, clusternet-agent, clusternet-scheduler andclusternet-hub.

Clusternet-agent is responsible for:

Auto-registering current cluster to parent cluster as a child cluster.
Report heartbeats of current cluster, including kubernetes version, running platform, health/readyz/livez status,etc;
setting up websocket connection that provides full-duplex communication channels over a single TCP connection to parent cluster.

Clusternet-scheduler is responsible for

scheduling resources/feeds to marched child clusters based on SchedulingStrategy.

Clusternet-hub is responsible for

approving cluster registration request and creating dedicated resources, suce as namespaces, servceaccounts and RBAC rules, for each child cluster;
Serving ad an aggregated apiserver(AA),which is used to provide shadow APIs and serve as a websocket server that maintain multiple active webscoket connections form child clusters;
providing Kubernetes-styled API to redirect/proxy/upgrade request to each child cluster.
coordinating and deploying applications to multiple clusters from a single set of APIs;
ClusterRegistrationRequest: This is cluster-agent created in parent-cluster for child-cluster.
```
1k get clsrr 
```
ManagedCluseter: clusternet-hub approved the clsrr and created this object
```
1k get mcls -A
```
HelmChart: helm chart configuration
Subscription: the resource for the child cluster. with a Base Object in corresponding namespace
Localization and Globalization
Base
Description

MultiCluster API

ServiceExport

ServiceExport, used to specify which service should be exposed across all clusters in the clusterset. ServiceExport must be created in each cluster that the underlying Service reside in. Creation of a ServiceExport in a cluster will signify that Service with the same name and namespace as the export should be visible to other clusters in the clusterset.

ServiceImport

ServcieImport is introduced to act as the in-cluster representation of a multi-cluster service in each importing cluster. This is analogous to the traditional Service type in Kubernetes, Importing clusters will have a corresponding ServiceImport for each uniquely named Service that has been exported within the clusterset, referenced by namespaced name. ServiceImport resources will be managed by the MCS implementation’s mcs-controller.

Debug of Clusternet

Reference

https://github.com/clusternet/clusternet/tree/main/examples/scheduling-with-mcs-api

https://github.com/kubernetes/community/tree/master/sig-multicluster

https://github.com/kubernetes/enhancements/tree/master/keps/sig-multicluster/1645-multi-cluster-services-api

1$env:HTTP_PROXY="proxy-prc.intel.com:913"
2$env:HTTPS_PROXY="proxy-prc.intel.com:913"

Airren Ren

clusternet