Adds mitigation to the kubernetes server parsing

clean up + symbol
use default values in case of failure

#428

controllers/factory/k8stools/version.go

@@ -4,25 +4,35 @@ import (
 	"fmt"
 	"k8s.io/apimachinery/pkg/version"
 	"strconv"
+	"strings"
 )
 
 var (
 	ServerMajorVersion uint64
 	ServerMinorVersion uint64
 )
 
-// TrySetKubernetesServerVersion parses kubernetes
-func TrySetKubernetesServerVersion(vi *version.Info) error {
-	v, err := strconv.ParseUint(vi.Minor, 10, 64)
+// SetKubernetesVersionWithDefaults parses kubernetes version response with given default versions
+func SetKubernetesVersionWithDefaults(vi *version.Info, defaultMinor, defaultMajor uint64) error {
+
+	var warnMessage string
+	minor := strings.Trim(vi.Minor, "+")
+	v, err := strconv.ParseUint(minor, 10, 64)
 	if err != nil {
-		return fmt.Errorf("cannot parse kubernetes server minor version: %q as uint: %w", vi.Minor, err)
+		v = defaultMinor
+		warnMessage = fmt.Sprintf("cannot parse minor kubernetes version response: %s, err: %s, using default: %d\n", vi.Minor, err, defaultMinor)
 	}
 	ServerMinorVersion = v
-	v, err = strconv.ParseUint(vi.Major, 10, 64)
+	major := strings.Trim(vi.Major, "+")
+	v, err = strconv.ParseUint(major, 10, 64)
 	if err != nil {
-		return fmt.Errorf("cannot parse kubernetes server major version: %q as uint: %w", vi.Major, err)
+		v = defaultMajor
+		warnMessage += fmt.Sprintf("cannot parse major kubernetes version response: %s, err: %s, using default: %d\n", vi.Major, err, defaultMajor)
 	}
 	ServerMajorVersion = v
+	if len(warnMessage) > 0 {
+		return fmt.Errorf(warnMessage)
+	}
 	return nil
 }
 

internal/manager/manager.go

@@ -36,13 +36,15 @@ var (
 	setupLog             = ctrl.Log.WithName("setup")
 	enableLeaderElection = flag.Bool("enable-leader-election", false, "Enable leader election for controller manager. "+
 		"Enabling this will ensure there is only one active controller manager.")
-	enableWebhooks      = flag.Bool("webhook.enable", false, "adds webhook server, you must mount cert and key or use cert-manager")
-	disableCRDOwnership = flag.Bool("controller.disableCRDOwnership", false, "disables CRD ownership add to cluster wide objects, must be disabled for clusters, lower than v1.16.0")
-	webhooksDir         = flag.String("webhook.certDir", "/tmp/k8s-webhook-server/serving-certs/", "root directory for webhook cert and key")
-	webhookCertName     = flag.String("webhook.certName", "tls.crt", "name of webhook server Tls certificate inside tls.certDir")
-	webhookKeyName      = flag.String("webhook.keyName", "tls.key", "name of webhook server Tls key inside tls.certDir")
-	metricsAddr         = flag.String("metrics-addr", ":8080", "The address the metric endpoint binds to.")
-	listenAddr          = flag.String("http.listenAddr", ":8435", "http server listen addr - serves victoria-metrics http server + metrics.")
+	enableWebhooks                = flag.Bool("webhook.enable", false, "adds webhook server, you must mount cert and key or use cert-manager")
+	disableCRDOwnership           = flag.Bool("controller.disableCRDOwnership", false, "disables CRD ownership add to cluster wide objects, must be disabled for clusters, lower than v1.16.0")
+	webhooksDir                   = flag.String("webhook.certDir", "/tmp/k8s-webhook-server/serving-certs/", "root directory for webhook cert and key")
+	webhookCertName               = flag.String("webhook.certName", "tls.crt", "name of webhook server Tls certificate inside tls.certDir")
+	webhookKeyName                = flag.String("webhook.keyName", "tls.key", "name of webhook server Tls key inside tls.certDir")
+	metricsAddr                   = flag.String("metrics-addr", ":8080", "The address the metric endpoint binds to.")
+	listenAddr                    = flag.String("http.listenAddr", ":8435", "http server listen addr - serves victoria-metrics http server + metrics.")
+	defaultKubernetesMinorVersion = flag.Uint64("default.kubernetesVersion.minor", 21, "Minor version of kubernetes server, if operator cannot parse actual kubernetes response")
+	defaultKubernetesMajorVersion = flag.Uint64("default.kubernetesVersion.major", 1, "Major version of kubernetes server, if operator cannot parse actual kubernetes response")
 )
 
 func init() {
@@ -265,8 +267,9 @@ func RunManager(ctx context.Context) error {
 	if err != nil {
 		return fmt.Errorf("cannot get kubernetes server version: %w", err)
 	}
-	if err := k8stools.TrySetKubernetesServerVersion(k8sServerVersion); err != nil {
-		return fmt.Errorf("cannot set kubernetes server version: %w", err)
+	if err := k8stools.SetKubernetesVersionWithDefaults(k8sServerVersion, *defaultKubernetesMinorVersion, *defaultKubernetesMajorVersion); err != nil {
+		// log error and do nothing, because we are using sane default values.
+		setupLog.Error(err, "cannot parse kubernetes version, using default flag values")
 	}
 
 	setupLog.Info("using kubernetes server version", "version", k8sServerVersion.String())