add unit tests for version compatibility check

pkg/descheduler/descheduler.go

@@ -18,12 +18,14 @@ package descheduler
 
 import (
  "context"
+ "errors"
  "fmt"
  "math"
  "strconv"
  "strings"
  "time"
 
+ "k8s.io/client-go/discovery"
  componentbaseconfig "k8s.io/component-base/config"
  "k8s.io/klog/v2"
 
@@ -76,7 +78,9 @@ func Run(ctx context.Context, rs *options.DeschedulerServer) error {
  }
 
  // Add k8s compatibility warnings to logs
- versionCompatibilityCheck(rs)
+ if err := validateVersionCompatibility(rs.Client.Discovery(), version.Get()); err != nil {
+ klog.Warning(err.Error())
+ }
 
  evictionPolicyGroupVersion, err := eutils.SupportEviction(rs.Client)
  if err != nil || len(evictionPolicyGroupVersion) == 0 {
@@ -92,7 +96,7 @@ func Run(ctx context.Context, rs *options.DeschedulerServer) error {
  }
 
  if rs.LeaderElection.LeaderElect && rs.DryRun {
- klog.V(1).InfoS("Warning: DryRun is set to True. You need to disable it to use Leader Election.")
+ klog.V(1).Info("Warning: DryRun is set to True. You need to disable it to use Leader Election.")
  }
 
  if rs.LeaderElection.LeaderElect && !rs.DryRun {
@@ -105,27 +109,34 @@ func Run(ctx context.Context, rs *options.DeschedulerServer) error {
  return runFn()
 }
 
-func versionCompatibilityCheck(rs *options.DeschedulerServer) {
- serverVersion, serverErr := rs.Client.Discovery().ServerVersion()
+func validateVersionCompatibility(discovery discovery.DiscoveryInterface, versionInfo version.Info) error {
+ serverVersion, serverErr := discovery.ServerVersion()
  if serverErr != nil {
- klog.V(1).InfoS("Warning: Get Kubernetes server version fail")
- return
+ return errors.New("failed to get Kubernetes server version")
  }
 
- deschedulerMinorVersion := strings.Split(version.Get().Minor, ".")[0]
+ deschedulerMinorVersion := strings.Split(versionInfo.Minor, ".")[0]
  deschedulerMinorVersionFloat, err := strconv.ParseFloat(deschedulerMinorVersion, 64)
  if err != nil {
- klog.Warning("Warning: Convert Descheduler minor version to float fail")
+ return errors.New("failed to convert Descheduler minor version to float")
  }
 
  kubernetesMinorVersionFloat, err := strconv.ParseFloat(serverVersion.Minor, 64)
  if err != nil {
- klog.Warning("Warning: Convert Kubernetes server minor version to float fail")
+ return errors.New("failed to convert Kubernetes server minor version to float")
  }
 
  if math.Abs(deschedulerMinorVersionFloat-kubernetesMinorVersionFloat) > 3 {
- klog.Warningf("Warning: Descheduler minor version %v is not supported on your version of Kubernetes %v.%v. See compatibility docs for more info: https://github.com/kubernetes-sigs/descheduler#compatibility-matrix", deschedulerMinorVersion, serverVersion.Major, serverVersion.Minor)
+ return fmt.Errorf(
+ "descheduler minor version %v is not supported on your version of Kubernetes %v.%v. "+
+ "See compatibility docs for more info: https://github.com/kubernetes-sigs/descheduler#compatibility-matrix",
+ deschedulerMinorVersion,
+ serverVersion.Major,
+ serverVersion.Minor,
+ )
  }
+
+ return nil
 }
 
 func cachedClient(

pkg/descheduler/descheduler_test.go

@@ -11,6 +11,8 @@ import (
  metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
  "k8s.io/apimachinery/pkg/conversion"
  "k8s.io/apimachinery/pkg/runtime"
+ apiversion "k8s.io/apimachinery/pkg/version"
+ fakediscovery "k8s.io/client-go/discovery/fake"
  fakeclientset "k8s.io/client-go/kubernetes/fake"
  core "k8s.io/client-go/testing"
  "sigs.k8s.io/descheduler/cmd/descheduler/app/options"
@@ -20,6 +22,7 @@ import (
  "sigs.k8s.io/descheduler/pkg/framework/plugins/defaultevictor"
  "sigs.k8s.io/descheduler/pkg/framework/plugins/removeduplicates"
  "sigs.k8s.io/descheduler/pkg/framework/plugins/removepodsviolatingnodetaints"
+ deschedulerversion "sigs.k8s.io/descheduler/pkg/version"
  "sigs.k8s.io/descheduler/test"
 )
 
@@ -245,6 +248,61 @@ func TestRootCancelWithNoInterval(t *testing.T) {
  }
 }
 
+func TestValidateVersionCompatibility(t *testing.T) {
+ type testCase struct {
+ name string
+ deschedulerMinor string
+ serverMinor string
+ expectError bool
+ }
+ testCases := []testCase{
+ {
+ name: "no error when descheduler minor equals to server minor",
+ deschedulerMinor: "26.0",
+ serverMinor: "26",
+ expectError: false,
+ },
+ {
+ name: "no error when descheduler minor is 3 behind server minor",
+ deschedulerMinor: "23.0",
+ serverMinor: "26",
+ expectError: false,
+ },
+ {
+ name: "no error when descheduler minor is 3 ahead of server minor",
+ deschedulerMinor: "26.0",
+ serverMinor: "23",
+ expectError: false,
+ },
+ {
+ name: "error when descheduler minor is 4 behind server minor",
+ deschedulerMinor: "22.0",
+ serverMinor: "26",
+ expectError: true,
+ },
+ {
+ name: "error when descheduler minor is 4 ahead of server minor",
+ deschedulerMinor: "27.0",
+ serverMinor: "23",
+ expectError: true,
+ },
+ }
+ client := fakeclientset.NewSimpleClientset()
+ fakeDiscovery, _ := client.Discovery().(*fakediscovery.FakeDiscovery)
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ fakeDiscovery.FakedServerVersion = &apiversion.Info{Major: "1", Minor: tc.serverMinor}
+ deschedulerVersion := deschedulerversion.Info{Major: "0", Minor: tc.deschedulerMinor}
+ err := validateVersionCompatibility(fakeDiscovery, deschedulerVersion)
+
+ hasError := err != nil
+ if tc.expectError != hasError {
+ t.Error("unexpected version compatibility behavior")
+ }
+ })
+ }
+}
+
 func podEvictionReactionFuc(evictedPods *[]string) func(action core.Action) (bool, runtime.Object, error) {
  return func(action core.Action) (bool, runtime.Object, error) {
  if action.GetSubresource() == "eviction" {