Network Policies

NetworkPolicy is a Kubernetes object used to restrict pod access. In CCE, by setting network policies, you can define ingress rules specifying the addresses to access pods or egress rules specifying the addresses pods can access. This is equivalent to setting up a firewall at the application layer to further ensure network security.

Network policies depend on the networking add-on of the cluster to which the policies apply.

By default, if a namespace does not have any policy, pods in the namespace accept traffic from any source and send traffic to any destination.

Network policy rules are classified into the following types:

namespaceSelector: selects particular namespaces for which all pods should be allowed as ingress sources or egress destinations.
podSelector: selects particular pods in the same namespace as the network policy which should be allowed as ingress sources or egress destinations.
ipBlock: selects particular IP blocks to allow as ingress sources or egress destinations.

Notes and Constraints

Only clusters that use the tunnel network model support network policies.
Egresses are not supported for network policies.
Network isolation is not supported for IPv6 addresses.

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

Diagram:

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

Figure 2 shows how namespaceSelector selects ingress sources.

Figure 2 namespaceSelector

Creating a Network Policy on the Console

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 Add. 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** Parameters for adding a 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.
Source Pod Label	Select the pod that allows this label to access.