Network Policies

Constraints

• Only clusters that use the tunnel network model support network policies. Network policies are classified into the following types:
  • Ingress: All versions support this type.
  • Egress: Only the following OSs and cluster versions support egress rules.

    OS	Cluster Version	Verified Kernel Version
    CentOS	v1.23 or later	3.10.0-1062.18.1.el7.x86_64 3.10.0-1127.19.1.el7.x86_64 3.10.0-1160.25.1.el7.x86_64
    EulerOS 2.5	v1.23 or later	3.10.0-862.14.1.5.h591.eulerosv2r7.x86_64 3.10.0-862.14.1.5.h687.eulerosv2r7.x86_64
    EulerOS 2.9	v1.23 or later	4.18.0-147.5.1.6.h541.eulerosv2r9.x86_64 4.18.0-147.5.1.6.h766.eulerosv2r9.x86_64

• Network isolation is not supported for IPv6 addresses.
• If upgrade to a cluster version that supports egress rules is performed in in-place mode, you cannot use egress rules because the node OS is not upgraded. In this case, reset the node.

Using Ingress Rules

• Using podSelector to specify the access scope

  apiVersion: networking.k8s.io/v1
  kind: NetworkPolicy
  metadata:
    name: test-network-policy
    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 traffic from the pods with the "role=frontend" label is allowed.
          matchLabels:
            role: frontend
      ports:                      # Only TCP can be used to access port 6379.
      - protocol: TCP
        port: 6379

  The following figure shows how podSelector works.

  Figure 1 podSelector
  

• Using namespaceSelector to specify the access scope

  apiVersion: networking.k8s.io/v1
  kind: NetworkPolicy
  metadata:
    name: test-network-policy
  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 traffic from the pods in the namespace with the "project=myproject" label is allowed.
          matchLabels:
            project: myproject
      ports:                      # Only TCP can be used to access port 6379.
      - protocol: TCP
        port: 6379

  The following figure shows how namespaceSelector works.

  Figure 2 namespaceSelector
  

Using Egress Rules

Egress supports not only podSelector and namespaceSelector, but also ipBlock.

Only clusters of version 1.23 or later support egress rules. Currently, nodes running EulerOS 2.5, EulerOS 2.9, and CentOS 7.X are supported.

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-client-a-via-except-cidr-egress-rule
  namespace: default
spec:
  policyTypes:                  # Must be specified for an egress rule.
    - Egress
  podSelector:                  # The rule takes effect for pods with the role=db label.
    matchLabels:
      role: db
  egress:                       # Egress rule
  - to:
    - ipBlock:
        cidr: 172.16.0.16/16    # Allow access to this CIDR block.
        except:
        - 172.16.0.40/32        # This CIDR block cannot be accessed. This value must fall within the range specified by cidr.

The following figure shows how ipBlock works.

Figure 3 ipBlock

You can define ingress and egress in the same rule.

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: test-network-policy
  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 traffic from the pods with the "role=frontend" label is allowed.
        matchLabels:
          role: frontend
    ports:                      # Only TCP can be used to access port 6379.
    - protocol: TCP
      port: 6379
  egress:                       # Egress rule
  - to:
    - podSelector:              # Only pods with the role=web label can be accessed.
        matchLabels:
          role: web

The following figure shows how to use ingress and egress together.

Figure 4 Using both ingress and egress

Creating a Network Policy on the Console

1. Log in to the CCE console and click the cluster name to access the cluster console.
2. Choose Networking in the navigation pane, click the Network Policies tab, and click Create Network Policy in the upper right corner.
   • Policy Name: Specify a network policy name.
   • Namespace: Select a namespace in which the network policy is applied.
   • Selector: Enter a label, select the pod to be associated, and click Confirm. You can also click Reference Workload Label to reference the label of an existing workload.
   • Inbound Rule: Click to add an inbound rule. For details about parameter settings, see Table 1.

     Table 1 Adding an inbound rule

     Parameter	Description
     Protocol & Port	Select the protocol type and port. Currently, TCP and UDP are supported.
     Source Namespace	Select a namespace whose objects can be accessed. If this parameter is not specified, the object belongs to the same namespace as the current policy.
     Source Pod Label	Allow accessing the pods with this label. If this parameter is not specified, all pods in the namespace can be accessed.

3. Click OK.