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Advanced

Configuring Health Check on Multiple LoadBalancer Service Ports

The health check annotation field of LoadBalancer Services has been upgraded from kubernetes.io/elb.health-check-option to kubernetes.io/elb.health-check-options. You can now specify unique health check configurations for specific Service ports if needed. These tailored settings do not affect other ports. If all ports use the same health check parameters, the old annotation will continue to work as expected, and you do not need to make any changes.

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
  • Either kubernetes.io/elb.health-check-option or kubernetes.io/elb.health-check-options can be configured.
  • The target_service_port field is mandatory and must be unique.
  • For a TCP port, the health check protocol can only be TCP or HTTP. For a UDP port, the health check protocol must be UDP.

Procedure

Configure health check for different Service ports. The following is an example using the kubernetes.io/elb.health-check-options annotation:

apiVersion: v1
kind: Service
metadata:
name: nginx
namespace: default
labels:
app: nginx
version: v1
annotations:
kubernetes.io/elb.class: union # Load balancer type
kubernetes.io/elb.id: <your_elb_id> # Load balancer ID. Replace it with the actual value.
kubernetes.io/elb.lb-algorithm: ROUND_ROBIN # Load balancer algorithm
kubernetes.io/elb.health-check-flag: 'on' # Enable ELB health check.
kubernetes.io/elb.health-check-options: '[
{
"protocol": "TCP",
"delay": "5",
"timeout": "10",
"max_retries": "3",
"target_service_port": "TCP:1",
"monitor_port": "22"
},
{
"protocol": "HTTP",
"delay": "5",
"timeout": "10",
"max_retries": "3",
"path": "/",
"target_service_port": "TCP:2",
"monitor_port": "22",
"expected_codes": "200-399"
}
]'
spec:
selector:
app: nginx
version: v1
externalTrafficPolicy: Cluster
ports:
- name: cce-service-0
targetPort: 1
nodePort: 0
port: 1
protocol: TCP
- name: cce-service-1
targetPort: 2
nodePort: 0
port: 2
protocol: TCP
type: LoadBalancer
loadBalancerIP: **.**.**.**
Table 1 elb.health-check-options

Parameter

Mandatory

Type

Description

target_service_port

Yes

String

Port for health check specified by spec.ports. The value consists of the protocol and port number, for example, TCP:80.

monitor_port

No

String

Re-specified port for health check. If this parameter is not specified, the service port is used by default.

NOTE:

Ensure that the port is in the listening state on the node where the pod is located. Otherwise, the health check result will be affected.

delay

No

String

Health check interval (s)

Value range: 1 to 50. Default value: 5

timeout

No

String

Health check timeout, in seconds.

Value range: 1 to 50. Default value: 10

max_retries

No

String

Maximum number of health check retries.

Value range: 1 to 10. Default value: 3

protocol

No

String

Health check protocol.

Default value: protocol of the associated Service

Options: TCP, UDP, and HTTP

path

No

String

Health check URL. This parameter needs to be configured when the protocol is HTTP.

Default value: /

Value range: 1-80 characters