inhibit the 2nd minor version upgrade

This PR prevents the cluster to be upgraded to x.y+2.z1 while
the upgrade to x.y+1.z2 from x.y.z3 is still in progress.

pkg/payload/precondition/clusterversion/upgradeable.go

@@ -2,6 +2,7 @@ package clusterversion
 
 import (
 	"context"
+	"fmt"
 	"strconv"
 	"strings"
 	"time"
@@ -63,6 +64,20 @@ func (pf *Upgradeable) Run(ctx context.Context, releaseContext precondition.Rele
 		}
 	}
 
+	currentVersion := GetCurrentVersion(cv.Status.History)
+	currentMinor := GetEffectiveMinor(currentVersion)
+	desiredMinor := GetEffectiveMinor(releaseContext.DesiredVersion)
+	klog.V(2).Infof("currentMinor %s releaseContext.DesiredVersion %s desiredMinor %s", currentMinor, releaseContext.DesiredVersion, desiredMinor)
+
+	// there is already a minor upgrade in progress
+	if minor := GetEffectiveMinor(cv.Status.Desired.Version); minorVersionUpgrade(currentMinor, minor) && minorVersionUpgrade(minor, desiredMinor) {
+		return &precondition.Error{
+			Reason:  "MinorVersionClusterUpgradeInProgress",
+			Message: fmt.Sprintf("The minor level upgrade to %s is not recommended while there is already a minor level upgrade from %s to %s in progress. It is recommended to wait until the existing minor level upgrade completes.", releaseContext.DesiredVersion, currentVersion, cv.Status.Desired.Version),
+			Name:    pf.Name(),
+		}
+	}
+
 	// if we are upgradeable==true we can always upgrade
 	up := resourcemerge.FindOperatorStatusCondition(cv.Status.Conditions, configv1.OperatorUpgradeable)
 	if up == nil {
@@ -80,11 +95,6 @@ func (pf *Upgradeable) Run(ctx context.Context, releaseContext precondition.Rele
 		return nil
 	}
 
-	currentVersion := GetCurrentVersion(cv.Status.History)
-	currentMinor := GetEffectiveMinor(currentVersion)
-	desiredMinor := GetEffectiveMinor(releaseContext.DesiredVersion)
-	klog.V(2).Infof("currentMinor %s releaseContext.DesiredVersion %s desiredMinor %s", currentMinor, releaseContext.DesiredVersion, desiredMinor)
-
 	// if there is no difference in the minor version (4.y.z where 4.y is the same for current and desired), then we can still upgrade
 	// if no cluster overrides have been set
 	if !minorVersionUpgrade(currentMinor, desiredMinor) {
@@ -141,7 +151,7 @@ func GetEffectiveMinor(version string) string {
 	return splits[1]
 }
 
-// minorVersionUpgrade returns true if the the desired update minor version number is greater
+// minorVersionUpgrade returns true if the desired update minor version number is greater
 // than the current version minor version number. Errors resulting from either version
 // number being unset or NaN are ignored simply resulting in false returned.
 func minorVersionUpgrade(currentMinor string, desiredMinor string) bool {

pkg/payload/precondition/clusterversion/upgradeable_test.go

@@ -60,11 +60,12 @@ func TestUpgradeableRun(t *testing.T) {
 	}
 
 	tests := []struct {
-		name           string
-		upgradeable    *configv1.ConditionStatus
-		currVersion    string
-		desiredVersion string
-		expected       string
+		name               string
+		upgradeable        *configv1.ConditionStatus
+		currVersion        string
+		desiredVersion     string
+		desiredVersionInCV string
+		expected           string
 	}{
 		{
 			name:           "first",
@@ -77,6 +78,19 @@ func TestUpgradeableRun(t *testing.T) {
 			desiredVersion: "4.2",
 			expected:       "",
 		},
+		{
+			name:               "move-(y+1) while move-y is in progress",
+			currVersion:        "4.6.3",
+			desiredVersionInCV: "4.7.2",
+			desiredVersion:     "4.8.1",
+			expected:           "The minor level upgrade to 4.8.1 is not recommended while there is already a minor level upgrade from 4.6.3 to 4.7.2 in progress. It is recommended to wait until the existing minor level upgrade completes.",
+		},
+		{
+			name:               "move-y with z while move-y is in progress",
+			currVersion:        "4.6.3",
+			desiredVersionInCV: "4.7.2",
+			desiredVersion:     "4.7.3",
+		},
 		{
 			name:           "move-y, with true condition",
 			upgradeable:    ptr(configv1.ConditionTrue),
@@ -114,6 +128,7 @@ func TestUpgradeableRun(t *testing.T) {
 				Spec:       configv1.ClusterVersionSpec{},
 				Status: configv1.ClusterVersionStatus{
 					History: []configv1.UpdateHistory{},
+					Desired: configv1.Release{Version: tc.desiredVersionInCV},
 				},
 			}
 			if len(tc.currVersion) > 0 {