Secure MCP Server

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: secure-mcp-network-policy
  namespace: secure-mcp
  labels:
    app.kubernetes.io/name: secure-mcp
    app.kubernetes.io/component: network-security
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/name: secure-mcp
  policyTypes:
    - Ingress
    - Egress
  ingress:
    # Allow traffic from ingress controller
    - from:
        - namespaceSelector:
            matchLabels:
              name: ingress-nginx
          podSelector:
            matchLabels:
              app.kubernetes.io/name: ingress-nginx
      ports:
        - protocol: TCP
          port: 3000
        - protocol: TCP
          port: 9090

    # Allow traffic from Prometheus
    - from:
        - namespaceSelector:
            matchLabels:
              name: monitoring
          podSelector:
            matchLabels:
              app: prometheus
      ports:
        - protocol: TCP
          port: 9090

    # Allow traffic between pods in the same namespace
    - from:
        - podSelector:
            matchLabels:
              app.kubernetes.io/name: secure-mcp
      ports:
        - protocol: TCP
          port: 3000

    # Allow traffic from specific IP ranges (internal networks)
    - from:
        - ipBlock:
            cidr: 10.0.0.0/8
            except:
              - 10.0.1.0/24  # Excluded subnet
        - ipBlock:
            cidr: 172.16.0.0/12
        - ipBlock:
            cidr: 192.168.0.0/16
      ports:
        - protocol: TCP
          port: 3000

  egress:
    # Allow DNS resolution
    - to:
        - namespaceSelector:
            matchLabels:
              name: kube-system
          podSelector:
            matchLabels:
              k8s-app: kube-dns
      ports:
        - protocol: UDP
          port: 53
        - protocol: TCP
          port: 53

    # Allow access to PostgreSQL
    - to:
        - podSelector:
            matchLabels:
              app.kubernetes.io/name: postgres
      ports:
        - protocol: TCP
          port: 5432

    # Allow access to Redis
    - to:
        - podSelector:
            matchLabels:
              app.kubernetes.io/name: redis
      ports:
        - protocol: TCP
          port: 6379

    # Allow access to Vault
    - to:
        - namespaceSelector:
            matchLabels:
              name: vault
          podSelector:
            matchLabels:
              app.kubernetes.io/name: vault
      ports:
        - protocol: TCP
          port: 8200

    # Allow access to Jaeger
    - to:
        - namespaceSelector:
            matchLabels:
              name: observability
          podSelector:
            matchLabels:
              app.kubernetes.io/name: jaeger
      ports:
        - protocol: TCP
          port: 4318
        - protocol: TCP
          port: 4317

    # Allow HTTPS traffic to external services
    - to:
        - ipBlock:
            cidr: 0.0.0.0/0
            except:
              - 169.254.169.254/32  # Block metadata service
      ports:
        - protocol: TCP
          port: 443
        - protocol: TCP
          port: 80

---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-default
  namespace: secure-mcp
  labels:
    app.kubernetes.io/name: secure-mcp
    app.kubernetes.io/component: network-security
spec:
  podSelector: {}
  policyTypes:
    - Ingress
    - Egress

---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-monitoring
  namespace: secure-mcp
  labels:
    app.kubernetes.io/name: secure-mcp
    app.kubernetes.io/component: network-security
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/component: monitoring
  policyTypes:
    - Ingress
  ingress:
    - from:
        - namespaceSelector:
            matchLabels:
              name: monitoring
      ports:
        - protocol: TCP
          port: 9090