Session Affinity with Gateway API ¶

Atlassian DC products require sticky sessions so that a user is consistently routed to the same pod. With the NGINX Ingress controller this was handled automatically via annotations:

nginx.ingress.kubernetes.io/affinity: "cookie"
nginx.ingress.kubernetes.io/affinity-mode: "persistent"

With Gateway API, session affinity is not part of the standard HTTPRoute spec and must be configured separately.

Cookie naming ¶

Use a dedicated routing cookie (for example ATLROUTE_<PRODUCT>) rather than the application's own JSESSIONID. This avoids conflicts with the application's session cookie and matches the approach used by NGINX Ingress.

Options at a glance ¶

Implementation-specific policies (recommended) ¶

Each Gateway API implementation provides its own policy resource for session affinity. Create the appropriate resource in the same namespace as your Helm release.

Envoy Gateway ¶

apiVersion: gateway.envoyproxy.io/v1alpha1
kind: BackendTrafficPolicy
metadata:
  name: <product>-session-affinity
  namespace: <your-namespace>
spec:
  targetRefs:
  - group: gateway.networking.k8s.io
    kind: HTTPRoute
    name: <release-name>-<product>
  loadBalancer:
    type: ConsistentHash
    consistentHash:
      type: Cookie
      cookie:
        name: ATLROUTE_<PRODUCT>
        ttl: 10h

Explore further:

• Envoy Gateway load balancing & session persistence: https://gateway.envoyproxy.io/latest/tasks/traffic/load-balancing/
• Envoy Gateway BackendTrafficPolicy API: https://gateway.envoyproxy.io/latest/api/extension_types/#backendtrafficpolicy
• Istio consistent-hash via DestinationRule: https://istio.io/latest/docs/reference/config/networking/destination-rule/#LoadBalancerSettings-ConsistentHashLB

Experimental sessionPersistence on HTTPRoute ¶

The Gateway API project has an experimental sessionPersistence field on HTTPRoute rules, tracked in GEP-1619. This field is not included in the standard-channel CRDs and will cause validation errors if those are installed.

Explore further:

• GEP-1619: https://gateway-api.sigs.k8s.io/geps/gep-1619/
• SessionPersistence field reference: https://gateway-api.sigs.k8s.io/reference/spec/#gateway.networking.k8s.io/v1.SessionPersistence
• Experimental CRDs install (pick a release): https://github.com/kubernetes-sigs/gateway-api/releases