Container Service for Kubernetes:Advanced usage of ALB Ingress

Annotation quick reference

All annotations apply to the metadata.annotations field of an Ingress resource unless noted otherwise in the Location column.

Route requests by URL path

Use the pathType field to control how ALB matches request paths. Three matching methods are supported:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: demo-path-prefix
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /
            backend:
              service:
                name: demo-service
                port:
                  number: 80
            pathType: Prefix

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: demo-path-prefix
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /
            backend:
              serviceName: demo-service
              servicePort: 80
            pathType: Prefix

curl <ADDRESS>/hello

{"hello":"coffee"}

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: demo-path
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /hello
            backend:
              service:
                name: demo-service
                port:
                  number: 80
            pathType: Exact

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: demo-path
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /hello
            backend:
              serviceName: demo-service
              servicePort: 80
            pathType: Exact

Redirect HTTP to HTTPS

Add the ssl-redirect annotation to redirect HTTP traffic on port 80 to HTTPS port 443.

Kubernetes 1.19 and later

apiVersion: v1
kind: Service
metadata:
  name: demo-service-ssl
  namespace: default
spec:
  ports:
    - name: port1
      port: 80
      protocol: TCP
      targetPort: 8080
  selector:
    app: demo-ssl
  sessionAffinity: None
  type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demo-ssl
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: demo-ssl
  template:
    metadata:
      labels:
        app: demo-ssl
    spec:
      containers:
        - image: registry.cn-hangzhou.aliyuncs.com/alb-sample/cafe:v1
          imagePullPolicy: IfNotPresent
          name: demo-ssl
          ports:
            - containerPort: 8080
              protocol: TCP
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/ssl-redirect: "true"
  name: demo-ssl
  namespace: default
spec:
  ingressClassName: alb
  tls:
  - hosts:
    - ssl.alb.ingress.top
  rules:
    - host: ssl.alb.ingress.top
      http:
        paths:
          - backend:
              service:
                name: demo-service-ssl
                port:
                  number: 80
            path: /
            pathType: Prefix

Configure backend protocol (HTTPS and gRPC)

ALB supports HTTPS and gRPC as backend protocols. Set the backend-protocol annotation on the Ingress.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/backend-protocol: "grpc"
  name: demo-alb-ingress
spec:
  ingressClassName: alb
  tls:
  - hosts:
    - demo.alb.ingress.top
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: grpc-demo-svc
            port:
              number: 9080

Configure regular expressions

Add the use-regex annotation to enable regular expression (regex) matching in path rules.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/use-regex: "true"
    alb.ingress.kubernetes.io/conditions.<YOUR-SVC-NAME>: |
      [{
        "type": "Path",
        "pathConfig": {
            "values": [
               "~*/pathvalue1",
               "/pathvalue2"
            ]
        }
       }]
  name: ingress-example
spec:
  ingressClassName: alb
  rules:
   - http:
      paths:
      - path: /test-path-for-alb
        pathType: Prefix
        backend:
          service:
            name: <YOUR-SVC-NAME>
            port:
              number: 88

Replace <YOUR-SVC-NAME> with the actual Service name. The name must match backend.service.name.

Regex flags

Matching behavior

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-example
  annotations:
    alb.ingress.kubernetes.io/use-regex: "true"
    alb.ingress.kubernetes.io/conditions.<YOUR-SVC-NAME>: |
      [
        {
          "type": "Path",
          "pathConfig": {
            "values": [
              "~*^/pathvalue1",
              "/pathvalue2"
            ]
          }
        }
      ]
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - path: /test-path-for-alb
            pathType: Prefix
            backend:
              service:
                name: <YOUR-SVC-NAME>
                port:
                  number: 88

Configure rewrite

ALB Ingress rewrites the request path before forwarding it to the backend Service. Two annotations work together:

• alb.ingress.kubernetes.io/rewrite-target: /<path>/${number} — Specifies the rewritten path. Use ${1}, ${2}, or ${3} to reference capturing groups from the original path (up to three groups).

• alb.ingress.kubernetes.io/use-regex: "true" — Enables regex matching in the path. This is enabled automatically when rewrite-target is set.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: rewrite-ingress
  annotations:
    alb.ingress.kubernetes.io/use-regex: "true"
    alb.ingress.kubernetes.io/rewrite-target: /${2}
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /something(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: rewrite-svc
            port:
              number: 9080

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: rewrite-ingress
  annotations:
    alb.ingress.kubernetes.io/use-regex: "true"
    alb.ingress.kubernetes.io/rewrite-target: /${2}?code=${3}
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /items/(.*)/(.*)/(.*)
        pathType: Prefix
        backend:
          service:
            name: rewrite-svc
            port:
              number: 9080

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: rewrite-ingress
  annotations:
    alb.ingress.kubernetes.io/use-regex: "true"
    alb.ingress.kubernetes.io/rewrite-target: /app-c/${2}
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /app-a(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: rewrite-svc
            port:
              number: 9080
      - path: /app-b(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: rewrite-svc
            port:
              number: 9080

Configure custom listening ports

Use the listen-ports annotation to expose a service on both port 80 (HTTP) and port 443 (HTTPS) simultaneously.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
  annotations:
    alb.ingress.kubernetes.io/listen-ports: '[{"HTTP": 80},{"HTTPS": 443}]'
spec:
  ingressClassName: alb
  tls:
  - hosts:
    - demo.alb.ingress.top
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /tea
        pathType: ImplementationSpecific
        backend:
          service:
            name: tea-svc
            port:
              number: 80

Configure forwarding rule priorities

ALB assigns forwarding rule priorities in the following order by default:

• Across Ingress resources: sorted lexicographically by namespace/name. A lexicographically smaller value gets a higher priority. Namespaces are compared first; if equal, names are compared character by character.

• Within the same Ingress: rules are prioritized by their order in the rules field. Rules listed earlier have higher priority.

To set a custom priority without changing namespace/name, use the order annotation:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
  annotations:
    alb.ingress.kubernetes.io/order: "2"
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /tea
        pathType: ImplementationSpecific
        backend:
          service:
            name: tea-svc
            port:
              number: 80

Implement canary release

ALB supports canary releases based on request headers, cookies, and traffic weight. Canary rules are evaluated in the following order of precedence:

Header > Cookie > Weight (highest to lowest)

Create a canary Ingress with alb.ingress.kubernetes.io/canary: "true", then add one or more of the canary routing annotations below.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/order: "1"
    alb.ingress.kubernetes.io/canary: "true"
    alb.ingress.kubernetes.io/canary-by-header: "location"
    alb.ingress.kubernetes.io/canary-by-header-value: "hz"
  name: demo-canary
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - backend:
              service:
                name: demo-service-hello
                port:
                  number: 80
            path: /hello
            pathType: ImplementationSpecific

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/order: "2"
    alb.ingress.kubernetes.io/canary: "true"
    alb.ingress.kubernetes.io/canary-by-cookie: "demo"
  name: demo-canary-cookie
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - backend:
              service:
                name: demo-service-hello
                port:
                  number: 80
            path: /hello
            pathType: ImplementationSpecific

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/order: "3"
    alb.ingress.kubernetes.io/canary: "true"
    alb.ingress.kubernetes.io/canary-weight: "50"
  name: demo-canary-weight
  namespace: default
spec:
  ingressClassName: alb
  rules:
    - http:
        paths:
          - backend:
              service:
                name: demo-service-hello
                port:
                  number: 80
            path: /hello
            pathType: ImplementationSpecific

Configure session persistence

ALB Ingress supports session persistence via cookie-based annotations. When enabled, the load balancer routes repeated requests from the same client to the same backend server.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress-v3
  annotations:
    alb.ingress.kubernetes.io/sticky-session: "true"
    alb.ingress.kubernetes.io/sticky-session-type: "Insert"
    alb.ingress.kubernetes.io/cookie-timeout: "1800"
    alb.ingress.kubernetes.io/cookie: "test"
spec:
  ingressClassName: alb
  rules:
  - http:
      paths:
      - backend:
          service:
            name: tea-svc
            port:
              number: 80
        path: /tea2
        pathType: ImplementationSpecific
      - backend:
          service:
            name: coffee-svc
            port:
              number: 80
        path: /coffee2
        pathType: ImplementationSpecific

Configure the load balancing algorithm

Use the backend-scheduler annotation to set the load balancing algorithm for backend server groups.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
  annotations:
    alb.ingress.kubernetes.io/backend-scheduler: "uch"
    alb.ingress.kubernetes.io/backend-scheduler-uch-value: "test"
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /tea
        pathType: ImplementationSpecific
        backend:
          service:
            name: tea-svc
            port:
              number: 80

Configure CORS

Use cross-origin resource sharing (CORS) annotations to control which origins, methods, and headers are allowed for cross-origin requests.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: alb-ingress
  annotations:
    alb.ingress.kubernetes.io/enable-cors: "true"
    alb.ingress.kubernetes.io/cors-allow-origin: "https://example.com:4443, http://aliyundoc.com"
    alb.ingress.kubernetes.io/cors-allow-methods: "GET,POST"
    alb.ingress.kubernetes.io/cors-allow-credentials: "true"
    alb.ingress.kubernetes.io/cors-max-age: "600"
    alb.ingress.kubernetes.io/cors-expose-headers: ""
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: cloud-nodeport
            port:
              number: 80

Enable backend persistent connections

Enabling backend persistent connections (keepalive) reuses existing TCP connections instead of opening a new one per request. This reduces TCP handshake overhead and improves throughput for high-traffic services.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: alb-ingress
  annotations:
    alb.ingress.kubernetes.io/backend-keepalive: "true"
spec:
  ingressClassName: alb
  rules:
  - host: demo.alb.ingress.top
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: cloud-nodeport
            port:
              number: 80

Enable IPv6 attachment for server groups

After enabling IPv6 attachment, ALB can route traffic to both IPv4 and IPv6 pods. The cluster must have the dual-stack feature enabled. See Create an ACK managed cluster.

Configure both the Service and the Ingress for dual-stack:

apiVersion: v1
kind: Service
metadata:
  name: tea-svc
spec:
  ipFamilyPolicy: RequireDualStack
  ipFamilies:
  - IPv4
  - IPv6
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
  selector:
    app: tea
  type: NodePort
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: cafe-ingress
  annotations:
    alb.ingress.kubernetes.io/enable-ipv6: "true"
spec:
  ingressClassName: alb
  rules:
   - host: demo.alb.ingress.top
     http:
      paths:
      - path: /tea
        pathType: Prefix
        backend:
          service:
            name: tea-svc
            port:
              number: 80

Configure backend slow start

When new pods are added to a backend server group, ALB immediately routes traffic to them. This can cause CPU or memory spikes, leading to errors. Slow start lets ALB gradually increase traffic to new pods over a configurable duration.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/slow-start-enabled: "true"
    alb.ingress.kubernetes.io/slow-start-duration: "100"
  name: alb-ingress
spec:
  ingressClassName: alb
  rules:
  - host: alb.ingress.alibaba.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: tea-svc
            port:
              number: 80

Configure connection draining

When a pod enters the Terminating state, ALB removes it from the backend server group but does not immediately close existing connections. Clients may continue sending requests to the terminating pod, causing errors or prolonged unavailability.

Connection draining tells ALB to maintain active connections for a specified duration after a pod is removed or fails a health check, then actively close them — ensuring a clean shutdown.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    alb.ingress.kubernetes.io/connection-drain-enabled: "true"
    alb.ingress.kubernetes.io/connection-drain-timeout: "199"
  name: alb-ingress
spec:
  ingressClassName: alb
  rules:
  - host: alb.ingress.alibaba.com
    http:
      paths:
      - path: /test
        pathType: Prefix
        backend:
          service:
            name: tea-svc
            port:
              number: 80

For more information, see Smooth service shutdown through ALB connection draining.

Disable cross-zone load balancing

By default, ALB distributes traffic across backend servers in different availability zones (AZs) within the same region. Disabling cross-zone load balancing restricts traffic distribution to backend servers in the same AZ.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: alb-ingress
  namespace: default
  annotations:
    alb.ingress.kubernetes.io/cross-zone-enabled: "false"
spec:
  ingressClassName: alb
  rules:
  - host: alb.ingress.alibaba.com
    http:
      paths:
      - path: /test
        pathType: Prefix
        backend:
          service:
            name: tea-svc
            port:
              number: 80

What's next

• Customize ALB Ingress forwarding rules

• Configure ALB listeners using an AlbConfig

• Implement canary release using an ALB Ingress