Network Policies

Relationships Between Network Policies and Cluster Types

• CCE DataPlane V2 is released with restrictions. To use this feature, submit a service ticket to CCE.
• Secure containers (such as Kata as the container runtime) are not supported by network policies.
• If you upgrade a CCE standard cluster with a tunnel network to a version that supports egress rules in in-place mode, the rules will not work because the node OS is not upgraded. In this case, reset the node.
• When a network policy is enabled for a cluster with a tunnel network, a pod's source IP address is embedded in the optional field of packets it sends to any Service CIDR block. This enables the configuration of network policy rules on the destination pod, taking into account the source IP address of the pod.

Using Ingress Rules Through YAML

• Scenario 1: Controlled by a preset network policy, a pod can only be accessed by pods with specific labels.
  Figure 1 podSelector
  

  The pod labeled with role=db only permits access to its port 6379 from pods labeled with role=frontend. To achieve this, take the following steps:

  1. Create the access-demo1.yaml file.

     vim access-demo1.yaml

     File content:

     apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: access-demo1
       namespace: default
     spec:
       podSelector:                  # The rule takes effect for pods with the role=db label.
         matchLabels:
           role: db
       ingress:                      # This is an ingress rule.
       - from:
         - podSelector:              # Only allows the access of the pods labeled with role=frontend.
             matchLabels:
               role: frontend
         ports:                      # Only TCP can be used to access port 6379.
         - protocol: TCP
           port: 6379

  2. Run the following command to create the network policy defined in the access-demo1.yaml file:

     kubectl apply -f access-demo1.yaml

     Expected output:

     networkpolicy.networking.k8s.io/access-demo1 created

• Scenario 2: Controlled by a preset network policy, a pod can only be accessed by pods in a specific namespace.
  Figure 2 namespaceSelector
  

  The pod labeled with role=db only permits access to its port 6379 from pods in the namespace labeled with project=myproject. To achieve this, take the following steps:

  1. Create the access-demo2.yaml file.

     vim access-demo2.yaml

     File content:

     apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: access-demo2
     spec:
       podSelector:                  # The rule takes effect for pods with the role=db label.
         matchLabels:
           role: db
       ingress:                      # This is an ingress rule.
       - from:
         - namespaceSelector:        # Only allows the access of the pods in the namespace labeled with project=myproject.
             matchLabels:
               project: myproject
         ports:                      # Only TCP can be used to access port 6379.
         - protocol: TCP
           port: 6379

  2. Run the following command to create the network policy defined in the access-demo2.yaml file:

     kubectl apply -f access-demo2.yaml

     Expected output:

     networkpolicy.networking.k8s.io/access-demo2 created

Using Egress Rules Through YAML

Clusters of v1.23 or later that use a tunnel network support egress rules.

Egress rules are only available for CCE Turbo clusters or other CCE clusters using a VPC network. The cluster version is v1.27.16-r10, v1.28.15-r0, v1.29.10-r0, v1.30.6-r0 or later, and DataPlane V2 must be enabled. Additionally, nodes in these clusters must run HCE OS 2.0.

• Scenario 1: Controlled by a preset network policy, pods can only access specific addresses.
  Figure 3 IPBlock
  

  The pods labeled role=db only allow access to 172.16.0.0/16, excluding 172.16.0.40/32. To achieve this, take the following steps:

  1. Create the access-demo3.yaml file.

     vim access-demo3.yaml

     File content:

     apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: access-demo3
       namespace: default
     spec:
       policyTypes:                  # This policy type must be specified for egress rules.
         - Egress
       podSelector:                  # The rule takes effect for pods with the role=db label.
         matchLabels:
           role: db
       egress:                       # This is an egress rule.
       - to:
         - ipBlock:
             cidr: 172.16.0.0/16    # Allows access to this CIDR block in the outbound direction.
             except:
             - 172.16.0.40/32        # Blocks access to this CIDR block. This CIDR block is in the allowed CIDR block.

  2. Run the following command to create the network policy defined in the access-demo3.yaml file:

     kubectl apply -f access-demo3.yaml

     Expected output:

     networkpolicy.networking.k8s.io/access-demo3 created

• Scenario 2: Controlled by a preset network policy, a pod can only be accessed by pods with specific labels, while this pod itself can only access specific pods.
  Figure 4 Using both ingress and egress
  

  The pod labeled with role=db only permits access to its port 6379 from pods labeled with role=frontend, and this pod can only access the pods labeled with role=web. You can use the same rule to configure both ingress and egress in a network policy. To achieve this, take the following steps:

  1. Create the access-demo4.yaml file.

     vim access-demo4.yaml

     File content:

     apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: access-demo4
       namespace: default
     spec:
       policyTypes:
       - Ingress
       - Egress
       podSelector:                  # The rule takes effect for pods with the role=db label.
         matchLabels:
           role: db
       ingress:                      # This is an ingress rule.
       - from:
         - podSelector:              # Only allows the access of the pods labeled with role=frontend.
             matchLabels:
               role: frontend
         ports:                      # Only TCP can be used to access port 6379.
         - protocol: TCP
           port: 6379
       egress:                       # This is an egress rule.
       - to:
         - podSelector:              # The rule takes effect for pods with the role=web label.
             matchLabels:
               role: web

  2. Run the following command to create the network policy defined the access-demo4.yaml file:

     kubectl apply -f access-demo4.yaml

     Expected output:

     networkpolicy.networking.k8s.io/access-demo4 created