chore: check all error returns in main code (#3184)

* chore: check all error returns in main code

* refactor: return named error from defer in DeepCopy()

* refactor: log sp.Refresh() errors instead of returning them

* ci: enforce errcheck linter

.golangci.yml

@@ -10,6 +10,7 @@ run:
 linters:
   disable-all: true
   enable:
+    - errcheck
     - goimports
     - gosimple
     - golint

cmd/addpool.go

@@ -88,24 +88,24 @@ func (apc *addPoolCmd) validate(cmd *cobra.Command) error {
 	}
 
 	if apc.resourceGroupName == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--resource-group must be specified")
 	}
 
 	if apc.location == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--location must be specified")
 	}
 
 	apc.location = helpers.NormalizeAzureRegion(apc.location)
 
 	if apc.apiModelPath == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--api-model must be specified")
 	}
 
 	if apc.nodePoolPath == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--nodepool must be specified")
 	}
 	return nil
@@ -144,7 +144,9 @@ func (apc *addPoolCmd) load() error {
 	}
 
 	if apc.containerService.Properties.IsCustomCloudProfile() {
-		writeCustomCloudProfile(apc.containerService)
+		if err = writeCustomCloudProfile(apc.containerService); err != nil {
+			return errors.Wrap(err, "error writing custom cloud profile")
+		}
 		if err = apc.containerService.Properties.SetCustomCloudSpec(api.AzureCustomCloudSpecParams{IsUpgrade: false, IsScale: true}); err != nil {
 			return errors.Wrap(err, "error parsing the api model")
 		}

cmd/deploy.go

@@ -121,7 +121,7 @@ func (dc *deployCmd) validateArgs(cmd *cobra.Command, args []string) error {
 		if len(args) == 1 {
 			dc.apimodelPath = args[0]
 		} else if len(args) > 1 {
-			cmd.Usage()
+			_ = cmd.Usage()
 			return errors.New("too many arguments were provided to 'deploy'")
 		}
 	}
@@ -225,7 +225,9 @@ func (dc *deployCmd) loadAPIModel() error {
 		if err != nil {
 			return errors.Wrap(err, "error parsing the api model")
 		}
-		writeCustomCloudProfile(dc.containerService)
+		if err = writeCustomCloudProfile(dc.containerService); err != nil {
+			return errors.Wrap(err, "error writing custom cloud profile")
+		}
 
 		if dc.containerService.Properties.CustomCloudProfile.IdentitySystem == "" || dc.containerService.Properties.CustomCloudProfile.IdentitySystem != dc.authProvider.getAuthArgs().IdentitySystem {
 			if dc.authProvider != nil {

cmd/generate.go

@@ -102,10 +102,10 @@ func (gc *generateCmd) validate(cmd *cobra.Command, args []string) error {
 		if len(args) == 1 {
 			gc.apimodelPath = args[0]
 		} else if len(args) > 1 {
-			cmd.Usage()
+			_ = cmd.Usage()
 			return errors.New("too many arguments were provided to 'generate'")
 		} else {
-			cmd.Usage()
+			_ = cmd.Usage()
 			return errors.New("--api-model was not supplied, nor was one specified as a positional argument")
 		}
 	}

cmd/get_logs.go

@@ -61,7 +61,7 @@ func newGetLogsCmd() *cobra.Command {
 		Long:  getLogsLongDescription,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if err := glc.validateArgs(); err != nil {
-				cmd.Usage()
+				_ = cmd.Usage()
 				return errors.Wrap(err, "validating get-logs args")
 			}
 			if err := glc.loadAPIModel(); err != nil {
@@ -77,11 +77,11 @@ func newGetLogsCmd() *cobra.Command {
 	command.Flags().StringVar(&glc.linuxScriptPath, "linux-script", "", "path to the log collection script to execute on the cluster's Linux nodes (required)")
 	command.Flags().StringVarP(&glc.outputDirectory, "output-directory", "o", "", "collected logs destination directory, derived from --api-model if missing")
 	command.Flags().BoolVarP(&glc.controlPlaneOnly, "control-plane-only", "", false, "get logs from control plane VMs only")
-	command.MarkFlagRequired("location")
-	command.MarkFlagRequired("api-model")
-	command.MarkFlagRequired("ssh-host")
-	command.MarkFlagRequired("linux-ssh-private-key")
-	command.MarkFlagRequired("linux-script") // optional once in VHD
+	_ = command.MarkFlagRequired("location")
+	_ = command.MarkFlagRequired("api-model")
+	_ = command.MarkFlagRequired("ssh-host")
+	_ = command.MarkFlagRequired("linux-ssh-private-key")
+	_ = command.MarkFlagRequired("linux-script") // optional once in VHD
 	return command
 }
 

cmd/rotate_certs.go

@@ -81,7 +81,7 @@ func newRotateCertsCmd() *cobra.Command {
 	f.StringVar(&rcc.masterFQDN, "apiserver", "", "apiserver endpoint (required)")
 	f.StringVarP(&rcc.outputDirectory, "output-directory", "o", "", "output directory where generated TLS artifacts will be saved (derived from DNS prefix if absent)")
 
-	f.MarkDeprecated("master-FQDN", "--apiserver is preferred")
+	_ = f.MarkDeprecated("master-FQDN", "--apiserver is preferred")
 
 	addAuthFlags(rcc.getAuthArgs(), f)
 

cmd/scale.go

@@ -85,8 +85,8 @@ func newScaleCmd() *cobra.Command {
 	f.StringVar(&sc.masterFQDN, "master-FQDN", "", "FQDN for the master load balancer that maps to the apiserver endpoint")
 	f.StringVar(&sc.masterFQDN, "apiserver", "", "apiserver endpoint (required to cordon and drain nodes)")
 
-	f.MarkDeprecated("deployment-dir", "--deployment-dir is no longer required for scale or upgrade. Please use --api-model.")
-	f.MarkDeprecated("master-FQDN", "--apiserver is preferred")
+	_ = f.MarkDeprecated("deployment-dir", "--deployment-dir is no longer required for scale or upgrade. Please use --api-model.")
+	_ = f.MarkDeprecated("master-FQDN", "--apiserver is preferred")
 
 	addAuthFlags(&sc.authArgs, f)
 
@@ -103,29 +103,29 @@ func (sc *scaleCmd) validate(cmd *cobra.Command) error {
 	}
 
 	if sc.resourceGroupName == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--resource-group must be specified")
 	}
 
 	if sc.location == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--location must be specified")
 	}
 
 	sc.location = helpers.NormalizeAzureRegion(sc.location)
 
 	if sc.newDesiredAgentCount == 0 {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--new-node-count must be specified")
 	}
 
 	if sc.apiModelPath == "" && sc.deploymentDirectory == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--api-model must be specified")
 	}
 
 	if sc.apiModelPath != "" && sc.deploymentDirectory != "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("ambiguous, please specify only one of --api-model and --deployment-dir")
 	}
 
@@ -160,7 +160,9 @@ func (sc *scaleCmd) load() error {
 	}
 
 	if sc.containerService.Properties.IsCustomCloudProfile() {
-		writeCustomCloudProfile(sc.containerService)
+		if err = writeCustomCloudProfile(sc.containerService); err != nil {
+			return errors.Wrap(err, "error writing custom cloud profile")
+		}
 
 		if err = sc.containerService.Properties.SetCustomCloudSpec(api.AzureCustomCloudSpecParams{IsUpgrade: false, IsScale: true}); err != nil {
 			return errors.Wrap(err, "error parsing the api model")
@@ -296,7 +298,7 @@ func (sc *scaleCmd) run(cmd *cobra.Command, args []string) error {
 		// VMAS Scale down Scenario
 		if currentNodeCount > sc.newDesiredAgentCount {
 			if sc.apiserverURL == "" {
-				cmd.Usage()
+				_ = cmd.Usage()
 				return errors.New("--apiserver is required to scale down a kubernetes cluster's agent pool")
 			}
 

cmd/upgrade.go

@@ -87,7 +87,7 @@ func newUpgradeCmd() *cobra.Command {
 	f.BoolVarP(&uc.controlPlaneOnly, "control-plane-only", "", false, "upgrade control plane VMs only, do not upgrade node pools")
 	addAuthFlags(uc.getAuthArgs(), f)
 
-	f.MarkDeprecated("deployment-dir", "deployment-dir is no longer required for scale or upgrade. Please use --api-model.")
+	_ = f.MarkDeprecated("deployment-dir", "deployment-dir is no longer required for scale or upgrade. Please use --api-model.")
 
 	return upgradeCmd
 }
@@ -101,12 +101,12 @@ func (uc *upgradeCmd) validate(cmd *cobra.Command) error {
 	}
 
 	if uc.resourceGroupName == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--resource-group must be specified")
 	}
 
 	if uc.location == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--location must be specified")
 	}
 	uc.location = helpers.NormalizeAzureRegion(uc.location)
@@ -122,17 +122,17 @@ func (uc *upgradeCmd) validate(cmd *cobra.Command) error {
 	}
 
 	if uc.upgradeVersion == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--upgrade-version must be specified")
 	}
 
 	if uc.apiModelPath == "" && uc.deploymentDirectory == "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("--api-model must be specified")
 	}
 
 	if uc.apiModelPath != "" && uc.deploymentDirectory != "" {
-		cmd.Usage()
+		_ = cmd.Usage()
 		return errors.New("ambiguous, please specify only one of --api-model and --deployment-dir")
 	}
 
@@ -175,7 +175,9 @@ func (uc *upgradeCmd) loadCluster() error {
 	}
 
 	if uc.containerService.Properties.IsCustomCloudProfile() {
-		writeCustomCloudProfile(uc.containerService)
+		if err = writeCustomCloudProfile(uc.containerService); err != nil {
+			return errors.Wrap(err, "error writing custom cloud profile")
+		}
 		if err = uc.containerService.Properties.SetCustomCloudSpec(api.AzureCustomCloudSpecParams{
 			IsUpgrade: true,
 			IsScale:   false,

pkg/api/convertertoagentpoolonlyapi.go

@@ -297,7 +297,9 @@ func isAgentPoolOnlyClusterJSON(contents []byte) bool {
 
 func propertiesAsMap(contents []byte) (map[string]interface{}, bool) {
 	var raw interface{}
-	json.Unmarshal(contents, &raw)
+	if err := json.Unmarshal(contents, &raw); err != nil {
+		return nil, false
+	}
 	jsonMap := raw.(map[string]interface{})
 	properties, propertiesPresent := jsonMap["properties"]
 	if !propertiesPresent {

pkg/api/defaults.go

@@ -1120,7 +1120,7 @@ func mapToString(valueMap map[string]string) string {
 
 func generateEtcdEncryptionKey() string {
 	b := make([]byte, 32)
-	rand.Read(b)
+	_, _ = rand.Read(b)
 	return base64.StdEncoding.EncodeToString(b)
 }
 

pkg/api/types.go

@@ -1148,11 +1148,11 @@ func (p *Properties) GetClusterID() string {
 		// from the master dns name
 		h := fnv.New64a()
 		if p.MasterProfile != nil {
-			h.Write([]byte(p.MasterProfile.DNSPrefix))
+			_, _ = h.Write([]byte(p.MasterProfile.DNSPrefix))
 		} else if p.HostedMasterProfile != nil {
-			h.Write([]byte(p.HostedMasterProfile.DNSPrefix))
+			_, _ = h.Write([]byte(p.HostedMasterProfile.DNSPrefix))
 		} else if len(p.AgentPoolProfiles) > 0 {
-			h.Write([]byte(p.AgentPoolProfiles[0].Name))
+			_, _ = h.Write([]byte(p.AgentPoolProfiles[0].Name))
 		}
 		r := rand.New(rand.NewSource(int64(h.Sum64())))
 		mutex.Lock()

pkg/armhelpers/azureclient.go

@@ -163,7 +163,9 @@ func NewAzureClientWithDeviceAuth(env azure.Environment, subscriptionID string)
 	if err != nil {
 		return nil, err
 	}
-	armSpt.Refresh()
+	if err = armSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	adRawToken := armSpt.Token()
 	adRawToken.Resource = env.GraphEndpoint
@@ -171,7 +173,9 @@ func NewAzureClientWithDeviceAuth(env azure.Environment, subscriptionID string)
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }
@@ -191,7 +195,9 @@ func NewAzureClientWithClientSecret(env azure.Environment, subscriptionID, clien
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }
@@ -211,7 +217,9 @@ func NewAzureClientWithClientSecretExternalTenant(env azure.Environment, subscri
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }
@@ -278,7 +286,9 @@ func newAzureClientWithCertificate(env azure.Environment, oauthConfig *adal.OAut
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }

pkg/armhelpers/azurestack/azureclient.go

@@ -89,7 +89,9 @@ func NewAzureClientWithClientSecret(env azure.Environment, subscriptionID, clien
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }
@@ -109,7 +111,9 @@ func NewAzureClientWithClientSecretExternalTenant(env azure.Environment, subscri
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }
@@ -181,7 +185,9 @@ func newAzureClientWithCertificate(env azure.Environment, oauthConfig *adal.OAut
 	if err != nil {
 		return nil, err
 	}
-	graphSpt.Refresh()
+	if err = graphSpt.Refresh(); err != nil {
+		log.Error(err)
+	}
 
 	return getClient(env, subscriptionID, tenantID, autorest.NewBearerAuthorizer(armSpt), autorest.NewBearerAuthorizer(graphSpt)), nil
 }

pkg/armhelpers/azurestack/converter.go

@@ -9,12 +9,11 @@ import (
 
 // DeepCopy dst and src should be the same type in different API version
 // dst should be pointer type
-func DeepCopy(dst, src interface{}) error {
-	defer func() error {
+func DeepCopy(dst, src interface{}) (err error) {
+	defer func() {
 		if r := recover(); r != nil {
-			return fmt.Errorf("fail to copy object %v", r)
+			err = fmt.Errorf("fail to copy object %v", r)
 		}
-		return nil
 	}()
 	dstValue := reflect.ValueOf(dst)
 	srcValue := reflect.ValueOf(src)
@@ -26,7 +25,7 @@ func DeepCopy(dst, src interface{}) error {
 		return fmt.Errorf("the dst type (%q) and src type (%q) are not the same", dstValue.Type().String(), srcValue.Type().String())
 	}
 	deepCopyInternal(dstValue, srcValue, 0)
-	return nil
+	return err
 }
 
 func deepCopyInternal(dstValue, srcValue reflect.Value, depth int) {

pkg/armhelpers/azurestack/deploymentError.go

@@ -79,7 +79,7 @@ func DeployTemplateSync(az armhelpers.AKSEngineClient, logger *logrus.Entry, res
 	// try to extract error from ARM Response
 	if deploymentExtended.Response.Response != nil && deploymentExtended.Body != nil {
 		buf := new(bytes.Buffer)
-		buf.ReadFrom(deploymentExtended.Body)
+		_, _ = buf.ReadFrom(deploymentExtended.Body)
 		logger.Infof("StatusCode: %d, Error: %s", deploymentExtended.Response.StatusCode, buf.String())
 		deploymentErr.Response = buf.Bytes()
 		deploymentErr.StatusCode = deploymentExtended.Response.StatusCode

pkg/armhelpers/converter.go

@@ -9,12 +9,11 @@ import (
 
 // DeepCopy dst and src should be the same type in different API version
 // dst should be pointer type
-func DeepCopy(dst, src interface{}) error {
-	defer func() error {
+func DeepCopy(dst, src interface{}) (err error) {
+	defer func() {
 		if r := recover(); r != nil {
-			return fmt.Errorf("fail to copy object %v", r)
+			err = fmt.Errorf("fail to copy object %v", r)
 		}
-		return nil
 	}()
 	dstValue := reflect.ValueOf(dst)
 	srcValue := reflect.ValueOf(src)
@@ -26,7 +25,7 @@ func DeepCopy(dst, src interface{}) error {
 		return fmt.Errorf("the dst type (%q) and src type (%q) are not the same", dstValue.Type().String(), srcValue.Type().String())
 	}
 	deepCopyInternal(dstValue, srcValue, 0)
-	return nil
+	return err
 }
 
 func deepCopyInternal(dstValue, srcValue reflect.Value, depth int) {

pkg/armhelpers/deploymentError.go

@@ -78,7 +78,7 @@ func DeployTemplateSync(az AKSEngineClient, logger *logrus.Entry, resourceGroupN
 	// try to extract error from ARM Response
 	if deploymentExtended.Response.Response != nil && deploymentExtended.Body != nil {
 		buf := new(bytes.Buffer)
-		buf.ReadFrom(deploymentExtended.Body)
+		_, _ = buf.ReadFrom(deploymentExtended.Body)
 		logger.Infof("StatusCode: %d, Error: %s", deploymentExtended.Response.StatusCode, buf.String())
 		deploymentErr.Response = buf.Bytes()
 		deploymentErr.StatusCode = deploymentExtended.Response.StatusCode

pkg/engine/armvariables.go

@@ -673,6 +673,6 @@ func getWindowsProfileVars(wp *api.WindowsProfile) map[string]interface{} {
 func getSizeMap() map[string]interface{} {
 	var sizeMap map[string]interface{}
 	sizeMapStr := fmt.Sprintf("{%s}", helpers.GetSizeMap())
-	json.Unmarshal([]byte(sizeMapStr), &sizeMap)
+	_ = json.Unmarshal([]byte(sizeMapStr), &sizeMap)
 	return sizeMap
 }

pkg/engine/customfiles.go

@@ -69,7 +69,7 @@ func buildConfigStringCustomFiles(source io.Reader, destinationFile string) stri
 
 func getBase64CustomFile(source io.Reader) string {
 	buf := new(bytes.Buffer)
-	buf.ReadFrom(source)
+	_, _ = buf.ReadFrom(source)
 	cfStr := buf.String()
 	cfStr = strings.Replace(cfStr, "\r\n", "\n", -1)
 	return getBase64EncodedGzippedCustomScriptFromStr(cfStr)

pkg/engine/engine.go

@@ -630,7 +630,7 @@ func getBase64EncodedGzippedCustomScript(csFilename string, cs *api.ContainerSer
 		panic(fmt.Sprintf("BUG: %s", err.Error()))
 	}
 	var buffer bytes.Buffer
-	templ.Execute(&buffer, cs)
+	_ = templ.Execute(&buffer, cs)
 	csStr := buffer.String()
 	csStr = strings.Replace(csStr, "\r\n", "\n", -1)
 	return getBase64EncodedGzippedCustomScriptFromStr(csStr)
@@ -645,7 +645,7 @@ func getStringFromBase64(str string) (string, error) {
 func getBase64EncodedGzippedCustomScriptFromStr(str string) string {
 	var gzipB bytes.Buffer
 	w := gzip.NewWriter(&gzipB)
-	w.Write([]byte(str))
+	_, _ = w.Write([]byte(str))
 	w.Close()
 	return base64.StdEncoding.EncodeToString(gzipB.Bytes())
 }
@@ -917,7 +917,7 @@ func getComponentsString(cs *api.ContainerService, sourcePath string) string {
 					return ""
 				}
 				var buffer bytes.Buffer
-				templ.Execute(&buffer, component)
+				_ = templ.Execute(&buffer, component)
 				input = buffer.String()
 			}
 			if componentName == common.ClusterInitComponentName {
@@ -974,7 +974,7 @@ func getAddonsString(cs *api.ContainerService, sourcePath string) string {
 					return ""
 				}
 				var buffer bytes.Buffer
-				templ.Execute(&buffer, addon)
+				_ = templ.Execute(&buffer, addon)
 				input = buffer.String()
 			}
 			result += getComponentString(input, "/etc/kubernetes/addons", setting.destinationFile)

pkg/engine/transform/apimodel_merger.go

@@ -90,17 +90,26 @@ func MergeValuesWithAPIModel(apiModelPath string, m map[string]APIModelValue) (s
 			arrayPath := fmt.Sprint("properties.", flagValue.arrayName)
 			arrayValue := jsonObj.Path(arrayPath)
 			if flagValue.arrayProperty != "" {
-				arrayValue.Index(flagValue.arrayIndex).SetP(flagValue.value, flagValue.arrayProperty)
+				c := arrayValue.Index(flagValue.arrayIndex)
+				if _, err = c.SetP(flagValue.value, flagValue.arrayProperty); err != nil {
+					return "", err
+				}
 			} else {
 				count, _ := arrayValue.ArrayCount()
 				for i := count; i <= flagValue.arrayIndex; i++ {
-					jsonObj.ArrayAppendP(nil, arrayPath)
+					if err = jsonObj.ArrayAppendP(nil, arrayPath); err != nil {
+						return "", err
+					}
 				}
 				arrayValue = jsonObj.Path(arrayPath)
-				arrayValue.SetIndex(flagValue.value, flagValue.arrayIndex)
+				if _, err = arrayValue.SetIndex(flagValue.value, flagValue.arrayIndex); err != nil {
+					return "", err
+				}
 			}
 		} else {
-			jsonObj.SetP(flagValue.value, fmt.Sprint("properties.", key))
+			if _, err = jsonObj.SetP(flagValue.value, fmt.Sprint("properties.", key)); err != nil {
+				return "", err
+			}
 		}
 	}
 

pkg/helpers/pki.go

@@ -322,7 +322,7 @@ func certificateToPem(derBytes []byte) []byte {
 		Bytes: derBytes,
 	}
 	pemBuffer := bytes.Buffer{}
-	pem.Encode(&pemBuffer, pemBlock)
+	_ = pem.Encode(&pemBuffer, pemBlock)
 
 	return pemBuffer.Bytes()
 }
@@ -333,7 +333,7 @@ func privateKeyToPem(privateKey *rsa.PrivateKey) []byte {
 		Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
 	}
 	pemBuffer := bytes.Buffer{}
-	pem.Encode(&pemBuffer, pemBlock)
+	_ = pem.Encode(&pemBuffer, pemBlock)
 
 	return pemBuffer.Bytes()
 }

pkg/operations/kubernetesupgrade/upgradecluster.go

@@ -437,7 +437,9 @@ func (uc *UpgradeCluster) addVMToUpgradeSets(vm compute.VirtualMachine, currentV
 		uc.Logger.Infof("Master VM name: %s, orchestrator: %s (MasterVMs)", *vm.Name, currentVersion)
 		*uc.MasterVMs = append(*uc.MasterVMs, vm)
 	} else {
-		uc.addVMToAgentPool(vm, true)
+		if err := uc.addVMToAgentPool(vm, true); err != nil {
+			uc.Logger.Errorf("Failed to add VM %s to agent pool: %s", *vm.Name, err)
+		}
 	}
 }
 
@@ -446,6 +448,8 @@ func (uc *UpgradeCluster) addVMToFinishedSets(vm compute.VirtualMachine, current
 		uc.Logger.Infof("Master VM name: %s, orchestrator: %s (UpgradedMasterVMs)", *vm.Name, currentVersion)
 		*uc.UpgradedMasterVMs = append(*uc.UpgradedMasterVMs, vm)
 	} else {
-		uc.addVMToAgentPool(vm, false)
+		if err := uc.addVMToAgentPool(vm, false); err != nil {
+			uc.Logger.Errorf("Failed to add VM %s to agent pool: %s", *vm.Name, err)
+		}
 	}
 }