diff --git a/dnsprovider/pkg/dnsprovider/providers/openstack/designate/rrchangeset.go b/dnsprovider/pkg/dnsprovider/providers/openstack/designate/rrchangeset.go
index 96249793c1..f29574e874 100644
--- a/dnsprovider/pkg/dnsprovider/providers/openstack/designate/rrchangeset.go
+++ b/dnsprovider/pkg/dnsprovider/providers/openstack/designate/rrchangeset.go
@@ -56,11 +56,11 @@ func (c *ResourceRecordChangeset) Apply() error {
 	for _, removal := range c.removals {
 		rrID, err := c.nameToID(removal.Name())
 		if err != nil {
-
+			return err
 		}
 		err = recordsets.Delete(c.zone.zones.iface.sc, zoneID, rrID).ExtractErr()
 		if err != nil {
-
+			return err
 		}
 	}
 
@@ -73,14 +73,14 @@ func (c *ResourceRecordChangeset) Apply() error {
 		}
 		_, err := recordsets.Create(c.zone.zones.iface.sc, zoneID, opts).Extract()
 		if err != nil {
-
+			return err
 		}
 	}
 
 	for _, upsert := range c.upserts {
 		rrID, err := c.nameToID(upsert.Name())
 		if err != nil {
-
+			return err
 		}
 		uopts := recordsets.UpdateOpts{
 			TTL:     int(upsert.Ttl()),
@@ -96,7 +96,7 @@ func (c *ResourceRecordChangeset) Apply() error {
 			}
 			_, err := recordsets.Create(c.zone.zones.iface.sc, zoneID, copts).Extract()
 			if err != nil {
-
+				return err
 			}
 		}
 	}
diff --git a/nodeup/pkg/model/context.go b/nodeup/pkg/model/context.go
index a374e634b7..a11c6ca5b6 100644
--- a/nodeup/pkg/model/context.go
+++ b/nodeup/pkg/model/context.go
@@ -398,13 +398,13 @@ func (c *NodeupModelContext) UseSecureKubelet() bool {
 
 	// @check if we have anything specific to master kubelet
 	if c.IsMaster {
-		if cluster.MasterKubelet != nil && cluster.MasterKubelet.AnonymousAuth != nil && *cluster.MasterKubelet.AnonymousAuth == false {
+		if cluster.MasterKubelet != nil && cluster.MasterKubelet.AnonymousAuth != nil && !*cluster.MasterKubelet.AnonymousAuth {
 			return true
 		}
 	}
 
 	// @check the default settings for master and kubelet
-	if cluster.Kubelet != nil && cluster.Kubelet.AnonymousAuth != nil && *cluster.Kubelet.AnonymousAuth == false {
+	if cluster.Kubelet != nil && cluster.Kubelet.AnonymousAuth != nil && !*cluster.Kubelet.AnonymousAuth {
 		return true
 	}
 
diff --git a/pkg/kubemanifest/visitor.go b/pkg/kubemanifest/visitor.go
index 9d025037c6..25c6d1f2dd 100644
--- a/pkg/kubemanifest/visitor.go
+++ b/pkg/kubemanifest/visitor.go
@@ -48,9 +48,9 @@ type Visitor interface {
 }
 
 func visit(visitor Visitor, data interface{}, path []string, mutator func(interface{})) error {
-	switch data.(type) {
+	switch data := data.(type) {
 	case string:
-		err := visitor.VisitString(path, data.(string), func(v string) {
+		err := visitor.VisitString(path, data, func(v string) {
 			mutator(v)
 		})
 		if err != nil {
@@ -58,7 +58,7 @@ func visit(visitor Visitor, data interface{}, path []string, mutator func(interf
 		}
 
 	case bool:
-		err := visitor.VisitBool(path, data.(bool), func(v bool) {
+		err := visitor.VisitBool(path, data, func(v bool) {
 			mutator(v)
 		})
 		if err != nil {
@@ -66,7 +66,7 @@ func visit(visitor Visitor, data interface{}, path []string, mutator func(interf
 		}
 
 	case float64:
-		err := visitor.VisitFloat64(path, data.(float64), func(v float64) {
+		err := visitor.VisitFloat64(path, data, func(v float64) {
 			mutator(v)
 		})
 		if err != nil {
@@ -74,7 +74,7 @@ func visit(visitor Visitor, data interface{}, path []string, mutator func(interf
 		}
 
 	case map[string]interface{}:
-		m := data.(map[string]interface{})
+		m := data
 		for k, v := range m {
 			path = append(path, k)
 
@@ -88,7 +88,7 @@ func visit(visitor Visitor, data interface{}, path []string, mutator func(interf
 		}
 
 	case []interface{}:
-		s := data.([]interface{})
+		s := data
 		for i, v := range s {
 			path = append(path, fmt.Sprintf("[%d]", i))
 
diff --git a/pkg/model/components/kubelet.go b/pkg/model/components/kubelet.go
index abb0f1a19c..1d014c4988 100644
--- a/pkg/model/components/kubelet.go
+++ b/pkg/model/components/kubelet.go
@@ -69,7 +69,7 @@ func (b *KubeletOptionsBuilder) BuildOptions(o interface{}) error {
 		if clusterSpec.Kubelet.AllowPrivileged != nil {
 			// If it is explicitly set to false, return an error, because this
 			// behavior is no longer supported in v1.14 (the default was true, prior).
-			if *clusterSpec.Kubelet.AllowPrivileged == false {
+			if !*clusterSpec.Kubelet.AllowPrivileged {
 				klog.Warningf("Kubelet's --allow-privileged flag is no longer supported in v1.14.")
 			}
 			// Explicitly set it to nil, so it won't be passed on the command line.
diff --git a/pkg/model/context.go b/pkg/model/context.go
index 1667ca0905..efd85cc1d8 100644
--- a/pkg/model/context.go
+++ b/pkg/model/context.go
@@ -307,7 +307,7 @@ func (m *KopsModelContext) UseLoadBalancerForAPI() bool {
 // HA - see https://github.com/kubernetes/kops/issues/4252
 func (m *KopsModelContext) UseLoadBalancerForInternalAPI() bool {
 	return m.UseLoadBalancerForAPI() &&
-		m.Cluster.Spec.API.LoadBalancer.UseForInternalApi == true
+		m.Cluster.Spec.API.LoadBalancer.UseForInternalApi
 }
 
 // UsePrivateDNS checks if we are using private DNS
diff --git a/pkg/resources/aws/aws.go b/pkg/resources/aws/aws.go
index 33673172d6..aaa0cb7637 100644
--- a/pkg/resources/aws/aws.go
+++ b/pkg/resources/aws/aws.go
@@ -230,7 +230,7 @@ func addUntaggedRouteTables(cloud awsup.AWSCloud, clusterName string, resources
 
 		isMain := false
 		for _, a := range rt.Associations {
-			if aws.BoolValue(a.Main) == true {
+			if aws.BoolValue(a.Main) {
 				isMain = true
 			}
 		}
diff --git a/protokube/pkg/protokube/etcd_manifest.go b/protokube/pkg/protokube/etcd_manifest.go
index d38993a401..e93cd8baf0 100644
--- a/protokube/pkg/protokube/etcd_manifest.go
+++ b/protokube/pkg/protokube/etcd_manifest.go
@@ -244,7 +244,7 @@ func buildCertificateDirectories(c *EtcdCluster) []string {
 	tracked := make(map[string]bool, 0)
 
 	for _, x := range []string{c.TLSCA, c.TLSCert, c.TLSKey, c.PeerCA, c.PeerKey, c.PeerKey} {
-		if x == "" || tracked[filepath.Dir(x)] == true {
+		if x == "" || tracked[filepath.Dir(x)] {
 			continue
 		}
 		tracked[filepath.Dir(x)] = true
diff --git a/upup/pkg/fi/cloudup/gce/op.go b/upup/pkg/fi/cloudup/gce/op.go
index 93248a3af9..49ecc0d68e 100644
--- a/upup/pkg/fi/cloudup/gce/op.go
+++ b/upup/pkg/fi/cloudup/gce/op.go
@@ -102,7 +102,7 @@ func waitForOp(op *compute.Operation, getOperation func(operationName string) (*
 	return wait.Poll(operationPollInterval, operationPollTimeoutDuration, func() (bool, error) {
 		start := time.Now()
 		//gce.operationPollRateLimiter.Accept()
-		duration := time.Now().Sub(start)
+		duration := time.Since(start)
 		if duration > 5*time.Second {
 			klog.Infof("pollOperation: throttled %v for %v", duration, opName)
 		}
@@ -112,7 +112,7 @@ func waitForOp(op *compute.Operation, getOperation func(operationName string) (*
 		}
 		done := opIsDone(pollOp)
 		if done {
-			duration := time.Now().Sub(opStart)
+			duration := time.Since(opStart)
 			if duration > 1*time.Minute {
 				// Log the JSON. It's cleaner than the %v structure.
 				enc, err := pollOp.MarshalJSON()
diff --git a/upup/pkg/fi/cloudup/spotinsttasks/elastigroup.go b/upup/pkg/fi/cloudup/spotinsttasks/elastigroup.go
index 9bcf69a4ac..9cdd36a1c5 100644
--- a/upup/pkg/fi/cloudup/spotinsttasks/elastigroup.go
+++ b/upup/pkg/fi/cloudup/spotinsttasks/elastigroup.go
@@ -803,9 +803,7 @@ func (_ *Elastigroup) update(cloud awsup.AWSCloud, a, e, changes *Elastigroup) e
 				}
 
 				types := make([]string, len(e.SpotInstanceTypes))
-				for i, typ := range e.SpotInstanceTypes {
-					types[i] = typ
-				}
+				copy(types, e.SpotInstanceTypes)
 
 				group.Compute.InstanceTypes.SetSpot(types)
 				changes.SpotInstanceTypes = nil
diff --git a/upup/pkg/fi/cloudup/terraform/hcl_printer.go b/upup/pkg/fi/cloudup/terraform/hcl_printer.go
index da18c2d9d0..4b177d6b5e 100644
--- a/upup/pkg/fi/cloudup/terraform/hcl_printer.go
+++ b/upup/pkg/fi/cloudup/terraform/hcl_printer.go
@@ -69,7 +69,7 @@ func (v *astSanitizer) visitObjectItem(o *ast.ObjectItem) {
 				v := text[1 : len(text)-1]
 				safe := true
 				for _, c := range v {
-					if strings.IndexRune(safeChars, c) == -1 {
+					if !strings.ContainsRune(safeChars, c) {
 						safe = false
 						break
 					}
diff --git a/upup/pkg/fi/utils/sanitize.go b/upup/pkg/fi/utils/sanitize.go
index b9c0c9a055..ed3b756c0d 100644
--- a/upup/pkg/fi/utils/sanitize.go
+++ b/upup/pkg/fi/utils/sanitize.go
@@ -28,14 +28,14 @@ func SanitizeString(s string) string {
 	var out bytes.Buffer
 	allowed := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-"
 	for _, c := range s {
-		if strings.IndexRune(allowed, c) != -1 {
+		if strings.ContainsRune(allowed, c) {
 			out.WriteRune(c)
 		} else {
 			out.WriteRune('_')
 		}
 	}
 
-	return string(out.Bytes())
+	return out.String()
 }
 
 // ExpandPath replaces common path aliases: ~ -> $HOME