Setting the Pod Ready Status Through the ELB Health Check

Notes and Constraints

• This feature is available in the following versions:
  • v1.19: v1.19.16-r5 or later
  • v1.21: v1.21.8-r0 or later
  • v1.23: v1.23.6-r0 or later
  • v1.25: v1.25.2-r0 or later
  • Versions later than v1.25
• This function applies only to passthrough scenarios, that is, scenarios where dedicated load balancers are used in CCE Turbo clusters.
• To use this function, configure the readinessGates field in the pod and specify the label target-health.elb.k8s.cce/{serviceName}, where {serviceName} indicates the service name.
• The pod ready status takes effect only when the ELB backend is initially connected. The subsequent health check status does not affect the pod ready status.

Setting the Pod Ready Status Through the ELB Health Check

To use pod readiness gates, perform the following steps:

1. Log in to the CCE console and click the cluster name to access the cluster console.
2. In the navigation pane, choose Workloads. In the upper right corner, click Create from YAML.
   YAML content:

   kind: Deployment
   apiVersion: apps/v1
   metadata:
     name: nginx
     namespace: default
     labels:
       version: v1
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: nginx
         version: v1
     template:
       metadata:
         labels:
           app: nginx
           version: v1
       spec:
         containers:
           - name: container-1
             image: nginx:latest
         imagePullSecrets:
           - name: default-secret
         readinessGates:
           - conditionType: target-health.elb.k8s.cce/specific-service-name  # Specifies the ServiceName.
     strategy:
       type: RollingUpdate
       rollingUpdate:
         maxUnavailable: 25%           # Works with the following two parameters to control the number of ELB backends and implement graceful rolling upgrade.
         maxSurge: 25%

3. Click OK. On the workload list, you can check the workload status and find that the pod is not ready.

   An event is displayed as follows:

   Pod not ready: correspondingcondition of pod readinessgate "target-health.elb.k8s.cce/specific-service-name" does not exist.

4. In the navigation pane, choose Services & Ingresses. In the upper right corner, click Create Service and configure the following parameters:
   • Service Name: The value must be the same as the value of readinessGates in the pod.
   • Service Type: Select LoadBalancer.
   • Selector: Click Reference Workload Label, select the workload created in the previous step, and click OK.
   • Load Balancer: Dedicated load balancers must be used. You can select an existing load balancer or automatically create a load balancer.
   • Health Check: Whether to enable health check. (If it is not configured, the health check is enabled by default.)
   Figure 1 Configuring a load balancer
   

5. Go to the ELB console and check the backend server group. The health check status is normal.
6. On the CCE console, the workload is in the Running status.