Configuring Storage Topology Awareness Using Helm

Procedure

Use a remote access tool, such as PuTTY, to log in to any master node in the Kubernetes cluster through the management IP address.
Go to the directory where the Helm project is located. If the previous Helm project cannot be found, copy the helm directory in the component package to any directory on the master node. For details about the component package path, see Table 1.
Go to the backend service configuration directory /examples/backend/ and back up the backend.yaml file.
```
cp backend.yaml backend.yaml.bak
```

Run the **vi **backend.yaml command to open the file and configure topology awareness as required. The following is an example. After the modification is complete, press Esc and enter :wq! to save the modification.

storage: "oceanstor-san"
name: "dorado-iscsi-155"
namespace: "huawei-csi"
urls:
  - "https://192.168.129.155:8088"
pools:
  - "StoragePool001"
parameters:
  protocol: "iscsi"
  portals:
    - "10.10.30.20"
    - "10.10.30.21"
supportedTopologies:
  - { "topology.kubernetes.io/region": "China-west", "topology.kubernetes.io/zone": "ChengDu" }
  - { "topology.kubernetes.io/region": "China-south","topology.kubernetes.io/zone": "ShenZhen" }
maxClientThreads: "30"

Run the following command to delete the storage backend to be modified. In the command, dorado-iscsi-155 indicates the storage backend name.
```
oceanctl delete backend dorado-iscsi-155 -n huawei-csi
```

Run the following command to create a storage backend.

oceanctl create backend -f ../examples/backend/backend.yaml -i yaml

Enter the storage user name and password as prompted.

Please enter this backend user name:admin
Please enter this backend password:

Run the vi StorageClass.yaml command to modify the .yaml file. Press I or Insert to enter the insert mode and add related parameters in the .yaml file. For details about the parameters, see Table 1. After the modification is complete, press Esc and enter :wq! to save the modification.

Add the following configuration items to the StorageClass.yaml file.

Example 1: Configure zone and region information in the StorageClass.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: example-storageclass
provisioner: csi.huawei.com
parameters:
  volumeType: lun
  allocType: thin
volumeBindingMode: WaitForFirstConsumer
allowedTopologies:
- matchLabelExpressions:
  - key: topology.kubernetes.io/zone
    values:
    - ChengDu
  - key: topology.kubernetes.io/region
    values:
    - China-west

Example 2: Configure protocol information in the StorageClass.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: protocol-example-storageclass
provisioner: csi.huawei.com
parameters:
  volumeType: lun
  allocType: thin
volumeBindingMode: WaitForFirstConsumer
allowedTopologies:
- matchLabelExpressions:
  - key: topology.kubernetes.io/protocol.iscsi
    values:
    - csi.huawei.com

Table 1 Parameter description

Parameter	Description	Remarks
volumeBindingMode	PersistentVolume binding mode, used to control the time when PersistentVolume resources are dynamically allocated and bound.	You can set this parameter to WaitForFirstConsumer or Immediate. WaitForFirstConsumer: indicates that the binding and allocation of the PersistentVolume are delayed until a Pod that uses the PVC is created. Immediate: The PersistentVolume is bound and allocated immediately after a PVC is created.
allowedTopologies.matchLabelExpressions	Topology information label, which is used to filter CSI backends and Kubernetes nodes. If the matching fails, PVCs or Pods cannot be created. Both key and value must be configured in a fixed format.	key: This parameter can be set to topology.kubernetes.io/zone or topology.kubernetes.io/region. topology.kubernetes.io/protocol.<protocol>: <protocol> indicates the protocol type and can be iscsi, fc, or nfs.
value: If key is topology.kubernetes.io/zone or topology.kubernetes.io/region, value must be the same as the topology label set in the prerequisites. If key is topology.kubernetes.io/protocol.<protocol>, value is fixed at csi.huawei.com.

Parameter

Description

Remarks

volumeBindingMode

PersistentVolume binding mode, used to control the time when PersistentVolume resources are dynamically allocated and bound.

You can set this parameter to WaitForFirstConsumer or Immediate.

WaitForFirstConsumer: indicates that the binding and allocation of the PersistentVolume are delayed until a Pod that uses the PVC is created.

Immediate: The PersistentVolume is bound and allocated immediately after a PVC is created.

allowedTopologies.matchLabelExpressions

Topology information label, which is used to filter CSI backends and Kubernetes nodes. If the matching fails, PVCs or Pods cannot be created.

Both key and value must be configured in a fixed format.

key: This parameter can be set to topology.kubernetes.io/zone or topology.kubernetes.io/region.

topology.kubernetes.io/protocol.<protocol>: <protocol> indicates the protocol type and can be iscsi, fc, or nfs.

value:

If key is topology.kubernetes.io/zone or topology.kubernetes.io/region, value must be the same as the topology label set in the prerequisites.

If key is topology.kubernetes.io/protocol.<protocol>, value is fixed at csi.huawei.com.

Run the following command to create a StorageClass based on the .yaml file.
```
kubectl create -f StorgeClass.yaml
```
Use the StorageClass to create a PVC with the topology capability. For details, see PVC Parameters for Dynamic Volume Provisioning.