Expose ACK Serverless Pods to Production Traffic via LoadBalancer Service - Container Service for Kubernetes

Because pods are created and deleted frequently, their IP addresses change constantly. A Kubernetes Service provides a stable network endpoint for a group of pods and distributes traffic across them, decoupling frontend clients from backend pods. Use the ACK console to create a Deployment and expose it with a Service.

Prerequisites

Before you begin, ensure that you have:

An ACK Serverless cluster. For more information, see ACK Serverless quick start

How Services work

A label selector identifies which pods a Service targets. When the Service receives traffic, it distributes requests across all pods whose labels match the selector.

The following table shows the three Service types and when to use each:

Service type	Access pattern	Use when
Cluster IP	Internal cluster IP address only (default)	Exposing the app to other workloads within the same cluster
Node Port	`<NodeIP>:<NodePort>` from outside the cluster	Direct node-level access; not available for ACK Serverless clusters
Server Load Balancer	Internet-facing or internal SLB instance	Exposing the app to external users or internal VPC consumers

For the full Kubernetes Service specification, see Kubernetes Services.

Step 1: Create a Deployment

Log on to the ACK console. In the left-side navigation pane, click Clusters.
On the Clusters page, click the name of the target cluster. In the left-side navigation pane, choose Workloads > Deployments.
In the upper-right corner of the Deployments page, click Create from YAML.

Select a sample template or paste a custom YAML manifest, then click Create. The following example deploys two NGINX replicas and exposes port 80:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment-basic
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9          # Replace with your image
        ports:
        - containerPort: 80         # This port is referenced in the Service port mapping

On the Deployments page, click the Deployment name or click Details in the Actions column to confirm it is running.

Step 2: Create a Service

In the left-side navigation pane of the cluster details page, choose Network > Services.
On the Services page, click Create.

In the Create Service dialog box, configure the parameters described in the following table, then click Create.

Parameter	Description
Name	A name for the Service.
Service Type	How the Service is accessed. See Service type details for guidance.
External Traffic Policy	Available only for Node Port and Server Load Balancer types. Local routes traffic only to pods on the node that received the request. Cluster allows traffic to be routed to pods on any node in the cluster. For a comparison, see Differences between external traffic policies.
Backend	The Deployment to associate with this Service. If left blank, no Endpoint objects are created. See Services without selectors.
Port Mapping	Maps the Service port (`port` field in YAML) to the container port (`targetPort` field in YAML). The container port must match the port exposed in the backend pod.
Annotations	Key-value annotations that configure the underlying SLB instance. Select Custom Annotation or Alibaba Cloud Annotation from the Type drop-down list. For example, `service.beta.kubernetes.io/alicloud-loadbalancer-bandwidth:2` caps bandwidth at 2 Mbit/s. For all supported annotations, see Use annotations to configure CLB instances.
Label	Labels used to identify this Service.

On the Services page, confirm the Service appears in the list. To access the backend application, click the hyperlink next to External Endpoint on the Service details page.

Service type details

Cluster IP

Cluster IP exposes the Service on an internal cluster IP address, making it reachable only from within the cluster. This is the default type and is suitable for services consumed only by other workloads in the same cluster.

To use a headless Service — for example, to integrate with a custom service discovery mechanism — select the Headless Service checkbox. This option is available only when Service Type is set to Cluster IP.

Node Port

Node Port maps a static port on each node to the Service, allowing access from outside the cluster at <NodeIP>:<NodePort>. The system automatically creates a Cluster IP Service to handle internal routing.

Note

Node Port is supported only for ACK clusters. ACK Serverless clusters do not support this type.

Server Load Balancer

Server Load Balancer (SLB) creates or reuses an SLB instance to expose the Service externally (internet-facing) or internally (VPC-facing). Traffic can be routed to Node Port or Cluster IP Services.

SLB instance options:

Create SLB Instance: Click Modify to change the instance specification.
Use Existing SLB Instance: Select an SLB instance from your account.

Usage notes:

If you use an existing SLB instance, the listeners of the SLB instance overwrite the listeners of the Service.
Services sharing the same SLB instance must use different frontend listener ports to avoid port conflicts.
Do not rename listeners or vServer groups that Kubernetes manages — Kubernetes uses these names as unique identifiers.
SLB instances cannot be shared across clusters.
An SLB instance created automatically for a Service cannot be reused by other Services. Only SLB instances created manually in the console or via API can be shared across multiple Services.

What's next

To update or delete the Service, click Update or Delete in the Actions column on the Services page.
To configure advanced load balancing settings, see Use annotations to configure CLB instances.
To learn about external traffic policy trade-offs, see Differences between external traffic policies.