Skip to main content

Connect a LwM2M Device

This document demonstrates the integration of LwM2M protocol devices with Shifu. Shifu communicates with the LeShan server via the LwM2M protocol, showcasing seamless device management and interaction.

Introduction to LwM2M protocol​

LwM2M (Lightweight M2M)is a lightweight IoT device management protocol developed by OMA SpecWorks (Open Mobile Alliance). It is specifically designed for resource-constrained devices, such as low-power sensors and embedded devices, providing remote management capabilities for device management and services. LwM2M operates on the CoAP (Constrained Application Protocol) protocol stack and uses UDP or DTLS as the transport layer protocol, making it suitable for low-bandwidth and unstable network environments.

The following section describes how to use Shifu to connect devices via the LwM2M protocol.

Pull and Deploy the Shifu Project​

Before pulling the project from GitHub, you need to download the relevant Git environment, which can be quickly installed using yum. After setting up Git, clone Shifu to your local machine.

sudo yum -y install git && git clone https://github.com/Edgenesis/shifu.git

Finally, please use the latest configuration file to ensure support for the latest protocols.

kubectl apply -f pkg/k8s/crd/install/shifu_install.yml

Get the Example​

The example provides two methods of integration: LwM2MDeviceShifuWithSecurity and LwM2MDeviceshifuWithoutSecurity. The choice depends on the security configuration (Security Mode) of the device. If the device does not have the corresponding security configuration set, use LwM2MDeviceshifuWithoutSecurity.

For demonstration purposes, this guide illustrates a LwM2M device with Security Mode set to DTLS. You can also simulate a LwM2M device using the leshan-client from the example files, which can be found in examples\lwM2MDeviceShifuWithSecurity\mockdevice.

Modify Configuration​

Navigate to examples\lwM2MDeviceShifuWithSecurity\lwM2M\lwm2m-edgedevice.yaml to configure the device's security settings. For example, our device uses DTLS for secure communication and authenticates using the Pre-Shared Key method. The encryption algorithm suite is TLS_PSK_WITH_AES_128_CCM_8, the PSK identifier is hint, and the key value is ABC123. The corresponding YAML file is as follows:

apiVersion: shifu.edgenesis.io/v1alpha1
...
...
  protocolSettings:
    LwM2MSetting:
      endpointName: leshan-client
      securityMode: DTLS
      dtlsMode: PSK
      cipherSuites: 
        - TLS_PSK_WITH_AES_128_CCM_8
      pskIdentity: hint
      pskKey: ABC123

Deploy LwM2M deviceShifu​

Execute the following command to deploy our deviceShifu:

kubectl apply -f examples/lwM2MDeviceShifuWithSecurity/lwM2M

After a short wait, you can see that the external LwM2M deviceShifu component is running normally with the following command:

$ kubectl get pods -n deviceshifu
NAME                                            READY   STATUS    RESTARTS      AGE
deviceshifu-lwm2m-deployment-794ddd9978-cn6hb   1/1     Running   4 (67m ago)   47h
leshan-client-65b78c78cb-gktbq                  1/1     Running   1 (67m ago)   2d

We can check the service status in the cluster:

$ kubectl get svc -n deviceshifu
NAME                         TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)                       AGE
deviceshifu-lwm2m-security   NodePort   10.43.50.246   <none>        80:30080/TCP,5684:30001/UDP   2d

We can access the corresponding service through the externally exposed TCP port: 30080, using NodePort. Here, we use curl for a simple test, but you can also use tools like Postman or Apifox for testing.

$ curl http://<Your Server IP>:30080/float_value
3.14159

Write data:

$ curl -X PUT http://<Your Server IP>:30080/float_value -d 88.88
Success

Read the float_value data again.

$ curl http://<Your Server IP>:30080/float_value
88.88

Fill in your server IP address in Your Server IP to perform a simple test.