From ef3e0fd02fdbe031a107903760d4ba12a62d647e Mon Sep 17 00:00:00 2001
From: Artyom Lukianov <alukiano@redhat.com>
Date: Tue, 2 Mar 2021 14:07:30 +0200
Subject: [PATCH] e2e node: wait for kubelet health check to pass after kubelet
 restart

Signed-off-by: Artyom Lukianov <alukiano@redhat.com>
---
 test/e2e_node/hugepages_test.go |  8 ++++++++
 test/e2e_node/util.go           | 24 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/test/e2e_node/hugepages_test.go b/test/e2e_node/hugepages_test.go
index 80e901f655a..d3c54c457dd 100644
--- a/test/e2e_node/hugepages_test.go
+++ b/test/e2e_node/hugepages_test.go
@@ -339,6 +339,14 @@ var _ = SIGDescribe("HugePages [Serial] [Feature:HugePages][NodeSpecialFeature:H
 			ginkgo.By("restarting kubelet to pick up pre-allocated hugepages")
 			// stop the kubelet and wait until the server will restart it automatically
 			stopKubelet()
+			// wait until the kubelet health check will fail
+			gomega.Eventually(func() bool {
+				return kubeletHealthCheck(kubeletHealthCheckURL)
+			}, time.Minute, time.Second).Should(gomega.BeFalse())
+			// wait until the kubelet health check will pass
+			gomega.Eventually(func() bool {
+				return kubeletHealthCheck(kubeletHealthCheckURL)
+			}, 2*time.Minute, 10*time.Second).Should(gomega.BeTrue())
 
 			waitForHugepages()
 
diff --git a/test/e2e_node/util.go b/test/e2e_node/util.go
index 6d06019e825..4300a993a9c 100644
--- a/test/e2e_node/util.go
+++ b/test/e2e_node/util.go
@@ -18,6 +18,7 @@ package e2enode
 
 import (
 	"context"
+	"crypto/tls"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -70,6 +71,8 @@ const (
 	defaultPodResourcesPath    = "/var/lib/kubelet/pod-resources"
 	defaultPodResourcesTimeout = 10 * time.Second
 	defaultPodResourcesMaxSize = 1024 * 1024 * 16 // 16 Mb
+	kubeletReadOnlyPort        = "10255"
+	kubeletHealthCheckURL      = "http://127.0.0.1:" + kubeletReadOnlyPort + "/healthz"
 )
 
 func getNodeSummary() (*stats.Summary, error) {
@@ -432,6 +435,27 @@ func stopKubelet() func() {
 	}
 }
 
+func kubeletHealthCheck(url string) bool {
+	insecureTransport := http.DefaultTransport.(*http.Transport).Clone()
+	insecureTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+	insecureHTTPClient := &http.Client{
+		Transport: insecureTransport,
+	}
+
+	req, err := http.NewRequest("HEAD", url, nil)
+	if err != nil {
+		return false
+	}
+	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", framework.TestContext.BearerToken))
+	resp, err := insecureHTTPClient.Do(req)
+	if err != nil {
+		klog.Warningf("Health check on %q failed, error=%v", url, err)
+	} else if resp.StatusCode != http.StatusOK {
+		klog.Warningf("Health check on %q failed, status=%d", url, resp.StatusCode)
+	}
+	return err == nil && resp.StatusCode == http.StatusOK
+}
+
 func toCgroupFsName(cgroupName cm.CgroupName) string {
 	if framework.TestContext.KubeletConfig.CgroupDriver == "systemd" {
 		return cgroupName.ToSystemd()