Endpoint Health Checker

A tool for checking Kubernetes Pod health status, supporting TCP port probing and ICMP probing with retry mechanism.

Features

• Support TCP port health check
• Support ICMP health check
• Configurable retry mechanism
• Configurable single probe timeout
• Parallel health checking
• Leader Election support
• Automatic Pod Readiness Gate updates

Configuration Options

Environment Variables

Environment Variable	Default Value	Description
HEALTH_CHECK_INTERVAL	1s	Health check interval
HEALTH_CHECK_TIMEOUT	1s	Single probe timeout
HEALTH_CHECK_CONCURRENCY	10	Number of concurrent worker threads
HEALTH_CHECK_RETRY_COUNT	10	Health check retry count
POD_NAME	hostname	Pod name
POD_NAMESPACE	kube-system	Pod namespace
LEASE_NAME	endpoint-health-checker-leader	Leader election lease name
LEASE_DURATION	4s	Leader election lease duration
RENEW_DEADLINE	2s	Leader election renew deadline
RETRY_PERIOD	500ms	Leader election retry period

Retry Mechanism

Health check supports configurable retry mechanism:

• Retry Count: Configured via HEALTH_CHECK_RETRY_COUNT environment variable, default is 10 times
• Single Timeout: Configured via HEALTH_CHECK_TIMEOUT environment variable, default is 1 second
• Retry Interval: 100ms delay between retries

Leader Election

The application uses Kubernetes Leader Election to ensure only one instance performs health checks:

• Lease Duration: How long the lease is valid (default: 4s)
• Renew Deadline: Maximum time to renew the lease (default: 2s)
• Retry Period: How often to retry acquiring the lease (default: 500ms)

Health Check Logic

1. If Pod defines ports, perform TCP port probing
2. If Pod has no defined ports, perform ICMP probing
3. Retry specified number of times after each probe failure
4. After all retries fail, set Pod's Readiness Gate to False
5. If any probe succeeds, set Pod's Readiness Gate to True

Deployment

Using Helm

helm install endpoint-health-checker ./charts/endpoint-health-checker

Customizing Leader Election

You can customize leader election parameters in the Helm values:

leaderElection:
  leaseName: "endpoint-health-checker-leader"
  leaseDuration: 4s
  renewDeadline: 2s
  retryPeriod: 500ms