Using the node selector

By default, the IBM Spectrum Scale Container Storage Interface driver gets deployed on all worker nodes. Node selector controls the Kubernetes worker nodes on which the IBM Spectrum Scale Container Storage Interface driver must run. It helps in cases where new worker nodes are added to Kubernetes cluster but do not have IBM Spectrum Scale installed. It helps in ensuring that sidecar pods are running on the desired nodes.

To configure node selector, perform the following steps:

Label the Kubernetes worker nodes where sidecar pods should run, as shown in the following example:
- ```
kubectl label node node1 infranode=1 --overwrite=true
```
- ```
kubectl label node node2 infranode=2 --overwrite=true
```
Note:
- Use specific labels like the one for attacher and provisioner sidecar pods, only if there is a requirement of running these sidecar pods for very specific nodes. Otherwise, use single label like scale=true for running sidecar pods and IBM Spectrum Scale Container Storage Interface driver DaemonSet.
- Nodes marked for running sidecar pods must be a subset of the nodes marked with the scale=true label.
Label the Kubernetes worker nodes where IBM Spectrum Scale Container Storage Interface driver must run, as shown:
```
kubectl label node node1 scale=true --overwrite=true
```

Configure the following parameters in the Operator custom resource (csiscaleoperators.csi.ibm.com_cr.yaml) under the "spec" section. IBM Spectrum Scale client must be installed and running on the nodes that have the scale=true label.

attacherNodeSelector:
   - key: "scale"
     value: "true"
#  - key: "infranode"       # Only if there is requirement of running Attacher 
#    value: "2"             # on specific Node

provisionerNodeSelector:
   - key: "scale"
     value: "true"
#  - key: "infranode".      # Only if there is requirement of running Provisioner
#    value: "1"             # on specific Node

snapshotterNodeSelector:
    - key: "scale"
      value: "true"
#   - key: "infranode"      # Only if there is requirement of running Snapshotter
#     value: "2"            # on specific Node

pluginNodeSelector:
   - key: "scale"
     value: "true"

resizerNodeSelector:
    - key: "scale"
      value: "true"
#   - key: "infranode"      # Only if there is requirement of running Resizer 
#     value: "2"            # on specific Node

Note: If you choose to run IBM Spectrum Scale Container Storage Interface driver on selective nodes using the nodeSelector, then make sure that the pod using IBM Spectrum Scale Container Storage Interface driver PVC is scheduled on the nodes where IBM Spectrum Scale Container Storage Interface driver is running.