Cloud Native Network 2.0

Model Definition

Figure 1 Cloud Native Network 2.0

• Pods running on an ECS use supplementary network interfaces to access external networks. Supplementary network interfaces are attached to the elastic network interfaces of ECSs through VLAN subinterfaces.
• To run a pod, bind a network interface to it. The maximum number of pods that can run on a single node depends on the number of network interfaces that can be bound to the node and the number of network interface ports available on the node.
• Traffic for communications between pods on a node, communications between pods on different nodes, and pod access to networks outside a cluster is forwarded through the elastic or supplementary network interfaces of VPC.

Notes and Constraints

Advantages and Disadvantages

• VPCs serve as the foundation for constructing container networks. Every pod has its own network interface and IP address, which simplifies network problem-solving and enhances performance.
• In the same VPC, network interfaces are directly bound to pods in a cluster, so that resources outside the cluster can directly communicate with containers within the cluster.
  Note

  Similarly, if the VPC is accessible to other VPCs or data centers, resources in other VPCs or data centers can directly communicate with containers in the cluster, provided there are no conflicts between the network CIDR blocks.

• The load balancing, security group, and EIP capabilities provided by VPC can be directly used by pods.

Application Scenarios

• High performance requirements: Cloud Native Network 2.0 uses VPC networks to construct container networks, eliminating the need for tunnel encapsulation or NAT required by container communications. This makes Cloud Native Network 2.0 ideal for scenarios that demand high bandwidth and low latency.
• Large-scale networking: Cloud Native Network 2.0 supports up to 2,000 ECS nodes and 100,000 pods.

Recommendation for CIDR Block Planning

• All subnets (including those created from the secondary CIDR blocks) in the VPC where the cluster resides cannot conflict with the Service CIDR blocks.
• Each CIDR block has sufficient IP addresses.
  • The IP addresses in cluster CIDR blocks must match the cluster scale. Otherwise, nodes cannot be created due to insufficient IP addresses.
  • The IP addresses in container CIDR blocks must match the service scale. Otherwise, pods cannot be created due to insufficient IP addresses.

Example of Cloud Native Network 2.0 Access

1. Use kubectl to access the cluster. For details, see Accessing a Cluster Using kubectl.
2. Create a Deployment in the cluster.

   Create the deployment.yaml file. The following shows an example:

   kind: Deployment
   apiVersion: apps/v1
   metadata:
     name: example
     namespace: default
   spec:
     replicas: 6
     selector:
       matchLabels:
         app: example
     template:
       metadata:
         labels:
           app: example
       spec:
         containers:
           - name: container-0
             image: 'nginx:perl'
             resources:
               limits:
                 cpu: 250m
                 memory: 512Mi
               requests:
                 cpu: 250m
                 memory: 512Mi
         imagePullSecrets:
           - name: default-secret
   
   

   Create the workload.

   kubectl apply -f deployment.yaml
   
   

3. Check the running pods.

   kubectl get pod -owide
   
   

   Command output:

   NAME                       READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
   example-5bdc5699b7-54v7g   1/1     Running   0          7s    10.1.18.2     10.1.0.167   <none>           <none>
   example-5bdc5699b7-6dzx5   1/1     Running   0          7s    10.1.18.216   10.1.0.186   <none>           <none>
   example-5bdc5699b7-gq7xs   1/1     Running   0          7s    10.1.16.63    10.1.0.144   <none>           <none>
   example-5bdc5699b7-h9rvb   1/1     Running   0          7s    10.1.16.125   10.1.0.167   <none>           <none>
   example-5bdc5699b7-s9fts   1/1     Running   0          7s    10.1.16.89    10.1.0.144   <none>           <none>
   example-5bdc5699b7-swq6q   1/1     Running   0          7s    10.1.17.111   10.1.0.167   <none>           <none>
   
   

   All pods use supplementary network interfaces, which are bound to the extended network interface of the node.

   For example, the IP address of the extended network interface on the node (10.1.0.167) is 10.1.17.172. On the network interfaces page, you can see that there are three supplementary network interfaces bound to the extended network interface whose IP address is 10.1.17.172. The IP addresses bound to these supplementary network interfaces are the IP addresses of the pods running on the node.

4. Log in to an ECS in the same VPC and access the IP address of a pod from outside the cluster. In this example, the accessed pod IP address is 10.1.18.2.

   curl 10.1.18.2
   
   

   If the following information is displayed, the workload can be accessed:

   <!DOCTYPE html>
   <html>
   <head>
   <title>Welcome to nginx!</title>
   <style>
       body {
           width: 35em;
           margin: 0 auto;
           font-family: Tahoma, Verdana, Arial, sans-serif;
       }
   </style>
   </head>
   <body>
   <h1>Welcome to nginx!</h1>
   <p>If you see this page, the nginx web server is successfully installed and
   working. Further configuration is required.</p>
   
   <p>For online documentation and support please refer to
   <a href="http://nginx.org/">nginx.org</a>.<br/>
   Commercial support is available at
   <a href="http://nginx.com/">nginx.com</a>.</p>
   
   <p><em>Thank you for using nginx.</em></p>
   </body>
   </html>
   
   

Helpful Links

• For details about the maximum number of pods that can run on a node in a cluster with different network models, see Maximum Number of Pods That Can Be Created on a Node.