From 7b1d87383ecd65bb25e5b479154d8cba45b6c91d Mon Sep 17 00:00:00 2001
From: Paco Xu <paco.xu@daocloud.io>
Date: Sun, 8 Oct 2023 11:08:59 +0800
Subject: [PATCH] add kubelet policy skew test for kubeadm

---
 cmd/kubeadm/app/constants/constants.go        |  1 -
 cmd/kubeadm/app/phases/upgrade/policy.go      |  1 -
 cmd/kubeadm/app/phases/upgrade/policy_test.go | 35 ++++++++++++++++---
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/cmd/kubeadm/app/constants/constants.go b/cmd/kubeadm/app/constants/constants.go
index a11a800fcde..2f0d30bd488 100644
--- a/cmd/kubeadm/app/constants/constants.go
+++ b/cmd/kubeadm/app/constants/constants.go
@@ -453,7 +453,6 @@ var (
 	MinimumControlPlaneVersion = getSkewedKubernetesVersion(-1)
 
 	// MinimumKubeletVersion specifies the minimum version of kubelet which kubeadm supports
-	// Refer to https://kubernetes.io/releases/version-skew-policy/#kubelet-1
 	MinimumKubeletVersion = getSkewedKubernetesVersion(-3)
 
 	// CurrentKubernetesVersion specifies current Kubernetes version supported by kubeadm
diff --git a/cmd/kubeadm/app/phases/upgrade/policy.go b/cmd/kubeadm/app/phases/upgrade/policy.go
index d3723dbaf2f..497e03747dd 100644
--- a/cmd/kubeadm/app/phases/upgrade/policy.go
+++ b/cmd/kubeadm/app/phases/upgrade/policy.go
@@ -35,7 +35,6 @@ const (
 	MaximumAllowedMinorVersionDowngradeSkew = 1
 
 	// MaximumAllowedMinorVersionKubeletSkew describes how many minor versions the control plane version and the kubelet can skew in a kubeadm cluster
-	// Refer to https://kubernetes.io/releases/version-skew-policy/#kubelet-1
 	MaximumAllowedMinorVersionKubeletSkew = 3
 )
 
diff --git a/cmd/kubeadm/app/phases/upgrade/policy_test.go b/cmd/kubeadm/app/phases/upgrade/policy_test.go
index 5d97eca84a7..a747046a361 100644
--- a/cmd/kubeadm/app/phases/upgrade/policy_test.go
+++ b/cmd/kubeadm/app/phases/upgrade/policy_test.go
@@ -90,6 +90,24 @@ func TestEnforceVersionPolicies(t *testing.T) {
 			},
 			newK8sVersion:         "v1.13.0",
 			expectedMandatoryErrs: 1, // can't upgrade two minor versions
+		},
+		{
+			name: "upgrading with n-3 kubelet is supported",
+			vg: &fakeVersionGetter{
+				clusterVersion: "v1.14.3",
+				kubeletVersion: "v1.12.3",
+				kubeadmVersion: "v1.15.0",
+			},
+			newK8sVersion: "v1.15.0",
+		},
+		{
+			name: "upgrading with n-4 kubelet is not supported",
+			vg: &fakeVersionGetter{
+				clusterVersion: "v1.14.3",
+				kubeletVersion: "v1.11.3",
+				kubeadmVersion: "v1.15.0",
+			},
+			newK8sVersion:         "v1.15.0",
 			expectedSkippableErrs: 1, // kubelet <-> apiserver skew too large
 		},
 		{
@@ -123,13 +141,22 @@ func TestEnforceVersionPolicies(t *testing.T) {
 			expectedMandatoryErrs: 1,
 		},
 		{
-			name: "the maximum skew between the cluster version and the kubelet versions should be one minor version. This may be forced through though.",
+			name: "the maximum skew between the cluster version and the kubelet versions should be three minor version.",
 			vg: &fakeVersionGetter{
-				clusterVersion: "v1.12.0",
+				clusterVersion: "v1.13.0",
 				kubeletVersion: "v1.10.8",
-				kubeadmVersion: "v1.12.0",
+				kubeadmVersion: "v1.13.0",
 			},
-			newK8sVersion:         "v1.12.0",
+			newK8sVersion: "v1.13.0",
+		},
+		{
+			name: "the maximum skew between the cluster version and the kubelet versions should be three minor version. This may be forced through though.",
+			vg: &fakeVersionGetter{
+				clusterVersion: "v1.14.0",
+				kubeletVersion: "v1.10.8",
+				kubeadmVersion: "v1.14.0",
+			},
+			newK8sVersion:         "v1.14.0",
 			expectedSkippableErrs: 1,
 		},
 		{