Deploying Applications to Multiple Clusters with Static Weight Scheduling

Scheduling applications of multiple replicas to several clusters by static cluster weight

This tutorial will walk you through how to deploy applications to multiple clusters with static weight scheduling. It is different from replication scheduling. When using static weight scheduling, the replicas of an application will be split based on cluster weights. For example, if you want to deploy a Deployment with 6 replicas to 2 clusters (“cluster-01” with weight 1, “cluster-02” with weight 2), then “cluster-01” will run such a Deployment with 2 replicas, “cluster-02” runs the other 4 replicas.

Defining Your Applications

Let’s see an example using static weight scheduling. Below Subscription “static-dividing-scheduling-demo” defines the target child clusters to be distributed to, and the resources to be deployed with.

# examples/static-dividing-scheduling/subscription.yaml
kind: Subscription
  name: static-dividing-scheduling-demo
  namespace: default
  subscribers: # defines the clusters to be distributed to
    - clusterAffinity:
 dc91021d-2361-4f6d-a404-7c33b9e01118 # PLEASE UPDATE THIS CLUSTER-ID TO YOURS!!!
      weight: 1 # Deployment bar/my-nginx will have 2 replicas running in this cluster
    - clusterAffinity:
 5f9da921-0437-4fea-a89d-42aa1ede9b25 # PLEASE UPDATE THIS CLUSTER-ID TO YOURS!!!
      weight: 2 # Deployment bar/my-nginx will have 4 replicas running in this cluster
  schedulingStrategy: Dividing
    type: Static
  feeds: # defines all the resources to be deployed with
    - apiVersion: v1
      kind: Namespace
      name: bar
    - apiVersion: v1
      kind: Service
      name: my-nginx-svc
      namespace: bar
    - apiVersion: apps/v1 # with a total of 6 replicas
      kind: Deployment
      name: my-nginx
      namespace: bar

The Deployment bar/my-nginx above will run in two clusters with a total of 6 replicas, while 2 replicas run in cluster with ID dc91021d-2361-4f6d-a404-7c33b9e01118, 4 replicas in cluster with ID 5f9da921-0437-4fea-a89d-42aa1ede9b25.

You can get the scheduling result by checking the status of Subscription static-dividing-scheduling-demo.

  - clusternet-v7wzq/clusternet-cluster-bb2xp
  - clusternet-wlf5b/clusternet-cluster-skxd4
  desiredReleases: 6
    - 2
    - 4
    v1/Namespace/qux: []
    v1/Service/qux/my-nginx-svc: []

Before applying this Subscription, please modify examples/static-dividing-scheduling/subscription.yaml with your clusterID.

If you want to apply overrides per cluster, please follow How to Set Overrides in Clusternet.

Applying Your Applications

After installing kubectl plugin kubectl-clusternet, you could run commands below to distribute this application to child clusters.

$ kubectl clusternet apply -f examples/static-dividing-scheduling/
namespace/bar created
deployment.apps/my-nginx created
service/my-nginx-svc created created
$ # or
$ # kubectl-clusternet apply -f examples/static-dividing-scheduling/

You can check aggregated status of feeds/resources running in each child clusters.