NetworkAttachmentDefinition

Scenario

In a CCE Turbo cluster, you can configure subnets and security groups for containers by namespace using NetworkAttachmentDefinition, a CRD resource in the cluster. If you want to configure a specified container subnet and security group for a specified namespace, you can create a custom container NetworkAttachmentDefinition and associate the container network configuration with the corresponding namespace. In this way, service subnets can be planned or services can be securely isolated.

Constraints

• Only the default-network supports container ENI prebinding. The creation speed of pods using the custom container network is slower than that of pods using the default-network. Therefore, this function is not suitable for ultra-fast pod scaling scenarios.
• The default container network configuration default-network cannot be deleted.
• To delete a NetworkAttachmentDefinition, delete pods (with the cni.yangtse.io/network-status annotation) created using the configuration in the corresponding namespace first. For details, see Deleting a Network Configuration.

Creating a NetworkAttachmentDefinition of the Namespace Type Using the CCE Console

1. Log in to the CCE console.
2. Click the cluster name to access the cluster console. Choose Settings in the navigation pane and click the Network tab.
   

   If default-network exists in the cluster, it will take effect for all pods for which no custom network is configured. Default container subnet in the network configuration area on the Overview page is the container subnet in default-network.

3. View Container Network Security Policy Configuration (Namespace Level). Click Adding a Container Network Security Policy. In the dialog box that is displayed, configure the container subnet and security group.
   • Name: Enter a name that contains a maximum of 253 characters. Do not use default-network, default, mgnt0, and mgnt1.
   • Namespace: Select the namespace to be associated. Namespaces associated with different container network configurations must be unique. If no namespace is available, click Create Namespace to create one.
   • Pod Subnet: Select a subnet. If no subnet is available, click Create Subnet to create a subnet. After the subnet is created, click the refresh button. A maximum of 20 subnets can be selected.
   • Associate Security Group: The default value is the container ENI security group. You can also click Create Security Group to create one. After the security group is created, click the refresh button. A maximum of five security groups can be selected.

4. Click OK. After the creation is complete, you will be redirected to the network configuration list. You can see that the newly added subnet is in the list.

Creating a NetworkAttachmentDefinition of the Namespace Type Using Kubectl

This section describes how to create a NetworkAttachmentDefinition of the namespace type using kubectl.

1. Use kubectl to connect to the cluster. For details, see Connecting to a Cluster Using kubectl.
2. Modify the networkattachment-test.yaml file.

   vi networkattachment-test.yaml

   apiVersion: k8s.cni.cncf.io/v1
   kind: NetworkAttachmentDefinition
   metadata:
     annotations:
       yangtse.io/project-id: 05e38**
     name: example
     namespace: kube-system
   spec:
     config: 
     '{
       "type":"eni-neutron",
       "args":{
         "securityGroups":"41891**",
         "subnets":[
           {
             "subnetID":"27d95**"
           }
         ]
       },
       "selector":{
         "namespaceSelector":{
           "matchLabels":{
             "kubernetes.io/metadata.name":"default"
           }
         }
       }
     }'

   Table 1 Key parameters

   Parameter	Mandatory	Type	Description
   apiVersion	Yes	String	API version. The value is fixed at k8s.cni.cncf.io/v1.
   kind	Yes	String	Type of the object to be created. The value is fixed at NetworkAttachmentDefinition.
   yangtse.io/project-id	Yes	String	Project ID.
   name	Yes	String	Configuration item name.
   namespace	Yes	String	Namespace of the configuration resource. The value is fixed to kube-system.
   config	Yes	Table 2 object	Configuration content, which is a string in JSON format.

   Table 2 config parameters

   Parameter	Mandatory	Type	Description
   type	Yes	String	The value is fixed at eni-neutron.
   args	No	Table 3 object	Configuration parameters.
   selector	No	Table 4 object	Namespace on which the configuration takes effect.

   Table 3 args parameters

   Parameter	Mandatory	Type	Description
   securityGroups	No	String	Security group ID. If no security group is planned, ensure that the security group is the same as that in default-network. How to obtain: Log in to the VPC console. In the navigation pane, choose Access Control > Security Groups. Click the target security group name and copy the ID on the Summary tab page.
   subnets	Yes	Array of subnetID Objects	List of container subnet IDs. At least one subnet ID must be entered. The format is as follows: [{"subnetID":"27d95**"},{"subnetID":"827bb**"},{"subnetID":"bdd6b**"}] Subnet ID not used by the cluster in the same VPC. How to obtain: Log in to the VPC console. In the navigation pane, choose Virtual Private Cloud > Subnets. Click the target subnet name and copy the Subnet ID on the Summary tab page.

   Table 4 selector parameters

   Parameter	Mandatory	Type	Description
   namespaceSelector	No	matchLabels Object	A Kubernetes standard selector. Enter the namespace label in the following format: "matchLabels":{ "kubernetes.io/metadata.name":"default" } The namespaces of different configurations cannot overlap.

3. Create a NetworkAttachmentDefinition.

   kubectl create -f networkattachment-test.yaml

   If information similar to the following is displayed, the NetworkAttachmentDefinition has been created.

   networkattachmentdefinition.k8s.cni.cncf.io/example created

Deleting a Network Configuration

You can delete the new network configuration or view its YAML file.

Before deleting a network configuration, delete the container corresponding to the configuration. Otherwise, the deletion fails.

1. Run the following command to filter the pod that uses the configuration in the cluster (example is an example configuration name and you should replace it):

   kubectl get po -A -o=jsonpath="{.items[?(@.metadata.annotations.cni\.yangtse\.io/network-status=='[{\"name\":\"example\"}]')]['metadata.namespace', 'metadata.name']}"

   The command output contains the pod name and namespace associated with the configuration.

2. Delete the owner of the pod. The owner may be a Deployment, StatefulSet, DaemonSet, or Job.