Allow egress from a Kubernetes pod to only specific FQDN/DNS with Azure CNI Network Policies-CodePudding

How can egress from a Kubernetes pod be limited to only specific FQDN/DNS with Azure CNI Network Policies?

This is something that can be achieved with:

Istio

apiVersion: config.istio.io/v1alpha2
kind: EgressRule
metadata:
  name: googleapis
  namespace: default
spec:
  destination:
      service: "*.googleapis.com"
  ports:
      - port: 443
        protocol: https

Cilium

apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
  name: "fqdn"
spec:
  endpointSelector:
    matchLabels:
      app: some-pod
  egress:
  - toFQDNs:
    - matchName: "api.twitter.com"  
  - toEndpoints:
    - matchLabels:
        "k8s:io.kubernetes.pod.namespace": kube-system
        "k8s:k8s-app": kube-dns
    toPorts:
    - ports:
      - port: "53"
        protocol: ANY
      rules:
        dns:
        - matchPattern: "*"

OpenShift

apiVersion: network.openshift.io/v1
kind: EgressNetworkPolicy
metadata:
  name: default-rules 
spec:
  egress: 
  - type: Allow
    to:
      dnsName: www.example.com
  - type: Deny
    to:
      cidrSelector: 0.0.0.0/0

How can something similar be done with Azure CNI Network Policies?

CodePudding user response：

Apply K8s network policies

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-rules
spec:
  podSelector:
    matchLabels:
      role: pod_role
  policyTypes:
  - Egress
  egress:
  - to:
    - ipBlock:
        cidr: 0.0.0.0/0
    - host: www.example.com

reference https://kubernetes.io/docs/concepts/services-networking/network-policies/

CodePudding user response：

ATM network policies with FQDN/DNS rules are not supported on AKS.

If you use Azure CNI & Azure Policy Plugin you get the default Kubernetes Network Policies.

If you use Azure CNI & Calico Policy Plugin you get advanced possibilities like Global Network Polices but not the FQDN/DNS one. This is a paid feature on Calico Cloud unfortunately.