OpenShift Container Platform

Enabling node auto-scaling for the hosted cluster

When you need more capacity in your hosted cluster on Red Hat OpenStack Platform (RHOSP) and spare agents are available, you can enable auto-scaling to install new worker nodes.

Procedure

To enable auto-scaling, enter the following command:

$ oc -n <hosted_cluster_namespace> patch nodepool <hosted_cluster_name> \
  --type=json \
  -p '[{"op": "remove", "path": "/spec/replicas"},{"op":"add", "path": "/spec/autoScaling", "value": { "max": 5, "min": 2 }}]'

Create a workload that requires a new node.

Create a YAML file that has the workload configuration, by using the following example:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: reversewords
  name: reversewords
  namespace: default
spec:
  replicas: 40
  selector:
    matchLabels:
      app: reversewords
  template:
    metadata:
      labels:
        app: reversewords
    spec:
      containers:
      - image: quay.io/mavazque/reversewords:latest
        name: reversewords
        resources:
          requests:
            memory: 2Gi

Save the file with the name workload-config.yaml.
Apply the YAML by entering the following command:
```
$ oc apply -f workload-config.yaml
```

Extract the admin-kubeconfig secret by entering the following command:

$ oc extract -n <hosted_cluster_namespace> \
  secret/<hosted_cluster_name>-admin-kubeconfig \
  --to=./hostedcluster-secrets --confirm

Example output

hostedcluster-secrets/kubeconfig

You can check if new nodes are in the Ready status by entering the following command:
```
$ oc --kubeconfig ./hostedcluster-secrets get nodes
```

To remove the node, delete the workload by entering the following command:

$ oc --kubeconfig ./hostedcluster-secrets -n <namespace> \
  delete deployment <deployment_name>

Wait for several minutes to pass without requiring the additional capacity. You can confirm that the node was removed by entering the following command:
```
$ oc --kubeconfig ./hostedcluster-secrets get nodes
```