kube-router/utils/node.go

package utils

import (
	"fmt"
	"os"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	apiv1 "k8s.io/client-go/pkg/api/v1"
)

// GetNodeObject returns the node API object for the node
func GetNodeObject(clientset *kubernetes.Clientset, hostnameOverride string) (*apiv1.Node, error) {

	// assuming kube-router is running as pod, first check env NODE_NAME
	nodeName := os.Getenv("NODE_NAME")
	if nodeName != "" {
		node, err := clientset.Core().Nodes().Get(nodeName, metav1.GetOptions{})
		if err == nil {
			return node, nil
		}
	}

	// if env NODE_NAME is not set then check if node is register with hostname
	hostName, _ := os.Hostname()
	node, err := clientset.Core().Nodes().Get(hostName, metav1.GetOptions{})
	if err == nil {
		return node, nil
	}

	// if env NODE_NAME is not set and node is not registered with hostname, then use host name override
	if hostnameOverride != "" {
		node, err = clientset.Core().Nodes().Get(hostnameOverride, metav1.GetOptions{})
		if err == nil {
			return node, nil
		}
	}

	return nil, fmt.Errorf("Failed to identify the node by NODE_NAME, hostname or --hostname-override")
}