diff --git a/common/go.mod b/common/go.mod
index 0174061de..befab8272 100644
--- a/common/go.mod
+++ b/common/go.mod
@@ -6,6 +6,7 @@ module github.com/d2iq-labs/capi-runtime-extensions/common
 go 1.21
 
 require (
+	github.com/onsi/gomega v1.27.10
 	github.com/spf13/pflag v1.0.5
 	k8s.io/apiextensions-apiserver v0.28.1
 	k8s.io/apimachinery v0.28.1
diff --git a/common/pkg/handlers/interfaces.go b/common/pkg/handlers/interfaces.go
index 75473d822..0c79c3ea5 100644
--- a/common/pkg/handlers/interfaces.go
+++ b/common/pkg/handlers/interfaces.go
@@ -3,75 +3,6 @@
 
 package handlers
 
-import (
-	"context"
-
-	"github.com/spf13/pflag"
-	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
-)
-
-type NamedHandler interface {
+type Named interface {
 	Name() string
 }
-
-type FlagConfigurableHandler interface {
-	AddFlags(prefix string, fs *pflag.FlagSet)
-}
-
-type BeforeClusterCreateLifecycleHandler interface {
-	BeforeClusterCreate(
-		context.Context,
-		*runtimehooksv1.BeforeClusterCreateRequest,
-		*runtimehooksv1.BeforeClusterCreateResponse,
-	)
-}
-type AfterControlPlaneInitializedLifecycleHandler interface {
-	AfterControlPlaneInitialized(
-		context.Context,
-		*runtimehooksv1.AfterControlPlaneInitializedRequest,
-		*runtimehooksv1.AfterControlPlaneInitializedResponse,
-	)
-}
-type BeforeClusterUpgradeLifecycleHandler interface {
-	BeforeClusterUpgrade(
-		context.Context,
-		*runtimehooksv1.BeforeClusterUpgradeRequest,
-		*runtimehooksv1.BeforeClusterUpgradeResponse,
-	)
-}
-type AfterControlPlaneUpgradeLifecycleHandler interface {
-	AfterControlPlaneUpgrade(
-		context.Context,
-		*runtimehooksv1.AfterControlPlaneUpgradeRequest,
-		*runtimehooksv1.AfterControlPlaneUpgradeResponse,
-	)
-}
-type BeforeClusterDeleteLifecycleHandler interface {
-	BeforeClusterDelete(
-		context.Context,
-		*runtimehooksv1.BeforeClusterDeleteRequest,
-		*runtimehooksv1.BeforeClusterDeleteResponse,
-	)
-}
-
-type DiscoverVariablesMutationHandler interface {
-	DiscoverVariables(
-		context.Context,
-		*runtimehooksv1.DiscoverVariablesRequest,
-		*runtimehooksv1.DiscoverVariablesResponse,
-	)
-}
-type GeneratePatchesMutationHandler interface {
-	GeneratePatches(
-		context.Context,
-		*runtimehooksv1.GeneratePatchesRequest,
-		*runtimehooksv1.GeneratePatchesResponse,
-	)
-}
-type ValidateTopologyMutationHandler interface {
-	ValidateTopology(
-		context.Context,
-		*runtimehooksv1.ValidateTopologyRequest,
-		*runtimehooksv1.ValidateTopologyResponse,
-	)
-}
diff --git a/common/pkg/handlers/lifecycle/interfaces.go b/common/pkg/handlers/lifecycle/interfaces.go
new file mode 100644
index 000000000..6dcc9dfd3
--- /dev/null
+++ b/common/pkg/handlers/lifecycle/interfaces.go
@@ -0,0 +1,46 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package lifecycle
+
+import (
+	"context"
+
+	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
+)
+
+type BeforeClusterCreate interface {
+	BeforeClusterCreate(
+		context.Context,
+		*runtimehooksv1.BeforeClusterCreateRequest,
+		*runtimehooksv1.BeforeClusterCreateResponse,
+	)
+}
+type AfterControlPlaneInitialized interface {
+	AfterControlPlaneInitialized(
+		context.Context,
+		*runtimehooksv1.AfterControlPlaneInitializedRequest,
+		*runtimehooksv1.AfterControlPlaneInitializedResponse,
+	)
+}
+type BeforeClusterUpgrade interface {
+	BeforeClusterUpgrade(
+		context.Context,
+		*runtimehooksv1.BeforeClusterUpgradeRequest,
+		*runtimehooksv1.BeforeClusterUpgradeResponse,
+	)
+}
+type AfterControlPlaneUpgrade interface {
+	AfterControlPlaneUpgrade(
+		context.Context,
+		*runtimehooksv1.AfterControlPlaneUpgradeRequest,
+		*runtimehooksv1.AfterControlPlaneUpgradeResponse,
+	)
+}
+type BeforeClusterDelete interface {
+	BeforeClusterDelete(
+		context.Context,
+		*runtimehooksv1.BeforeClusterDeleteRequest,
+		*runtimehooksv1.BeforeClusterDeleteResponse,
+	)
+}
diff --git a/common/pkg/handlers/mutation/interfaces.go b/common/pkg/handlers/mutation/interfaces.go
new file mode 100644
index 000000000..1a4a67d6c
--- /dev/null
+++ b/common/pkg/handlers/mutation/interfaces.go
@@ -0,0 +1,32 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package mutation
+
+import (
+	"context"
+
+	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
+)
+
+type DiscoverVariables interface {
+	DiscoverVariables(
+		context.Context,
+		*runtimehooksv1.DiscoverVariablesRequest,
+		*runtimehooksv1.DiscoverVariablesResponse,
+	)
+}
+type GeneratePatches interface {
+	GeneratePatches(
+		context.Context,
+		*runtimehooksv1.GeneratePatchesRequest,
+		*runtimehooksv1.GeneratePatchesResponse,
+	)
+}
+type ValidateTopology interface {
+	ValidateTopology(
+		context.Context,
+		*runtimehooksv1.ValidateTopologyRequest,
+		*runtimehooksv1.ValidateTopologyResponse,
+	)
+}
diff --git a/common/pkg/openapi/patterns/distribution.go b/common/pkg/openapi/patterns/distribution.go
new file mode 100644
index 000000000..e2a00a8e2
--- /dev/null
+++ b/common/pkg/openapi/patterns/distribution.go
@@ -0,0 +1,15 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package patterns
+
+const (
+	// See: https://github.com/distribution/reference/blob/v0.5.0/regexp.go#L53
+	NameSeparator = `(?:[._]|__|[-]+)`
+
+	// See: https://github.com/distribution/reference/blob/v0.5.0/regexp.go#L123C18-L123C65
+	PathComponent = Alphanumeric + `(` + NameSeparator + Alphanumeric + `)*`
+
+	// See: https://github.com/distribution/reference/blob/v0.5.0/regexp.go#L130
+	ImageRegistry = `(` + DNS1123Subdomain + `|` + IPv6 + `)` + OptionalPort + `(/` + PathComponent + `)*`
+)
diff --git a/common/pkg/openapi/patterns/generic.go b/common/pkg/openapi/patterns/generic.go
new file mode 100644
index 000000000..62d9645ca
--- /dev/null
+++ b/common/pkg/openapi/patterns/generic.go
@@ -0,0 +1,9 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package patterns
+
+const (
+	// See: https://github.com/distribution/reference/blob/v0.5.0/regexp.go#L44C2-L44C28
+	Alphanumeric = `[a-z0-9]+`
+)
diff --git a/common/pkg/openapi/patterns/net.go b/common/pkg/openapi/patterns/net.go
new file mode 100644
index 000000000..38560672e
--- /dev/null
+++ b/common/pkg/openapi/patterns/net.go
@@ -0,0 +1,13 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package patterns
+
+const (
+	// See: https://github.com/distribution/reference/blob/v0.5.0/regexp.go#L91
+	IPv6 = `\[(?:[a-fA-F0-9:]+)\]`
+
+	Port = `:[0-9]+`
+
+	OptionalPort = `(` + Port + `)?`
+)
diff --git a/common/pkg/server/server.go b/common/pkg/server/server.go
index 50fdbe8ab..2169248dd 100644
--- a/common/pkg/server/server.go
+++ b/common/pkg/server/server.go
@@ -15,10 +15,12 @@ import (
 	ctrl "sigs.k8s.io/controller-runtime"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/lifecycle"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 )
 
 type Server struct {
-	allExtensionHandlers []handlers.NamedHandler
+	allExtensionHandlers []handlers.Named
 
 	webhookPort    int
 	webhookCertDir string
@@ -28,7 +30,7 @@ type Server struct {
 	enabledHandlers []string
 }
 
-func NewServer(extensionHandlers ...handlers.NamedHandler) *Server {
+func NewServer(extensionHandlers ...handlers.Named) *Server {
 	// catalog contains all information about RuntimeHooks.
 	catalog := runtimecatalog.New()
 
@@ -87,7 +89,7 @@ func (s *Server) Start(ctx context.Context) error {
 			continue
 		}
 
-		if t, ok := h.(handlers.BeforeClusterCreateLifecycleHandler); ok {
+		if t, ok := h.(lifecycle.BeforeClusterCreate); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.BeforeClusterCreate,
 				Name:        strings.ToLower(h.Name()),
@@ -98,7 +100,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.AfterControlPlaneInitializedLifecycleHandler); ok {
+		if t, ok := h.(lifecycle.AfterControlPlaneInitialized); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.AfterControlPlaneInitialized,
 				Name:        strings.ToLower(h.Name()),
@@ -109,7 +111,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.BeforeClusterUpgradeLifecycleHandler); ok {
+		if t, ok := h.(lifecycle.BeforeClusterUpgrade); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.BeforeClusterUpgrade,
 				Name:        strings.ToLower(h.Name()),
@@ -120,7 +122,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.AfterControlPlaneUpgradeLifecycleHandler); ok {
+		if t, ok := h.(lifecycle.AfterControlPlaneUpgrade); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.AfterControlPlaneUpgrade,
 				Name:        h.Name(),
@@ -131,7 +133,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.BeforeClusterDeleteLifecycleHandler); ok {
+		if t, ok := h.(lifecycle.BeforeClusterDelete); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.BeforeClusterDelete,
 				Name:        strings.ToLower(h.Name()),
@@ -142,7 +144,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.DiscoverVariablesMutationHandler); ok {
+		if t, ok := h.(mutation.DiscoverVariables); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.DiscoverVariables,
 				Name:        strings.ToLower(h.Name()),
@@ -153,7 +155,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.GeneratePatchesMutationHandler); ok {
+		if t, ok := h.(mutation.GeneratePatches); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.GeneratePatches,
 				Name:        strings.ToLower(h.Name()),
@@ -164,7 +166,7 @@ func (s *Server) Start(ctx context.Context) error {
 			}
 		}
 
-		if t, ok := h.(handlers.ValidateTopologyMutationHandler); ok {
+		if t, ok := h.(mutation.ValidateTopology); ok {
 			if err := webhookServer.AddExtensionHandler(server.ExtensionHandler{
 				Hook:        runtimehooksv1.ValidateTopology,
 				Name:        strings.ToLower(h.Name()),
diff --git a/common/pkg/testutils/capitest/variables.go b/common/pkg/testutils/capitest/variables.go
new file mode 100644
index 000000000..95065a343
--- /dev/null
+++ b/common/pkg/testutils/capitest/variables.go
@@ -0,0 +1,83 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package capitest
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	"github.com/onsi/gomega"
+	"github.com/onsi/gomega/gstruct"
+	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
+	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
+
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/testutils/openapi"
+)
+
+type VariableTestDef struct {
+	Name        string
+	Vals        any
+	ExpectError bool
+}
+
+func ValidateVariable[T mutation.DiscoverVariables](
+	t *testing.T,
+	variableName string,
+	variableSchema *clusterv1.VariableSchema,
+	handlerCreator func() T,
+	variableTestDefs ...VariableTestDef,
+) {
+	t.Helper()
+
+	t.Parallel()
+
+	for idx := range variableTestDefs {
+		tt := variableTestDefs[idx]
+
+		t.Run(tt.Name, func(t *testing.T) {
+			t.Parallel()
+
+			g := gomega.NewWithT(t)
+			h := handlerCreator()
+			resp := &runtimehooksv1.DiscoverVariablesResponse{}
+			h.DiscoverVariables(
+				context.Background(),
+				&runtimehooksv1.DiscoverVariablesRequest{},
+				resp,
+			)
+
+			g.Expect(resp.Status).To(gomega.Equal(runtimehooksv1.ResponseStatusSuccess))
+			g.Expect(resp.Variables).To(gomega.HaveLen(1))
+
+			variable := resp.Variables[0]
+			g.Expect(variable).To(gstruct.MatchFields(gstruct.IgnoreExtras, gstruct.Fields{
+				"Name":     gomega.Equal(variableName),
+				"Required": gomega.BeFalse(),
+				"Schema":   gomega.Equal(*variableSchema),
+			}))
+
+			encodedVals, err := json.Marshal(tt.Vals)
+			g.Expect(err).NotTo(gomega.HaveOccurred())
+
+			validateErr := openapi.ValidateClusterVariable(
+				&clusterv1.ClusterVariable{
+					Name:  variableName,
+					Value: apiextensionsv1.JSON{Raw: encodedVals},
+				},
+				&variable,
+				field.NewPath(variableName),
+			).ToAggregate()
+
+			if tt.ExpectError {
+				g.Expect(validateErr).To(gomega.HaveOccurred())
+			} else {
+				g.Expect(validateErr).NotTo(gomega.HaveOccurred())
+			}
+		})
+	}
+}
diff --git a/docs/content/http-proxy.md b/docs/content/http-proxy.md
index 8b1c03ba4..1e7c9b753 100644
--- a/docs/content/http-proxy.md
+++ b/docs/content/http-proxy.md
@@ -34,10 +34,10 @@ spec:
       - name: proxy
         value:
           http: http://example.com
-          https: http://example.com
+          https: https://example.com
           no:
-            - http://no-proxy-1.example.com
-            - http://no-proxy-2.example.com
+            - no-proxy-1.example.com
+            - no-proxy-2.example.com
 ```
 
 Applying this configuration will result in new bootstrap files on the `KubeadmControlPlaneTemplate`
diff --git a/go.mod b/go.mod
index ef993ba1c..765747ca0 100644
--- a/go.mod
+++ b/go.mod
@@ -21,6 +21,7 @@ require (
 	k8s.io/client-go v0.28.1
 	k8s.io/component-base v0.28.1
 	k8s.io/klog/v2 v2.100.1
+	k8s.io/utils v0.0.0-20230726121419-3b25d923346b
 	sigs.k8s.io/cluster-api v1.5.1
 	sigs.k8s.io/controller-runtime v0.16.1
 )
@@ -88,7 +89,6 @@ require (
 	k8s.io/apiserver v0.28.1 // indirect
 	k8s.io/cluster-bootstrap v0.27.2 // indirect
 	k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9 // indirect
-	k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
 	sigs.k8s.io/yaml v1.3.0 // indirect
diff --git a/go.sum b/go.sum
index 992cd0277..b59852a6a 100644
--- a/go.sum
+++ b/go.sum
@@ -512,8 +512,8 @@ k8s.io/klog/v2 v2.100.1 h1:7WCHKK6K8fNhTqfBhISHQ97KrnJNFZMcQvKp7gP/tmg=
 k8s.io/klog/v2 v2.100.1/go.mod h1:y1WjHnz7Dj687irZUWR/WLkLc5N1YHtjLdmgWjndZn0=
 k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9 h1:LyMgNKD2P8Wn1iAwQU5OhxCKlKJy0sHc+PcDwFB24dQ=
 k8s.io/kube-openapi v0.0.0-20230717233707-2695361300d9/go.mod h1:wZK2AVp1uHCp4VamDVgBP2COHZjqD1T68Rf0CM3YjSM=
-k8s.io/utils v0.0.0-20230406110748-d93618cff8a2 h1:qY1Ad8PODbnymg2pRbkyMT/ylpTrCM8P2RJ0yroCyIk=
-k8s.io/utils v0.0.0-20230406110748-d93618cff8a2/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
+k8s.io/utils v0.0.0-20230726121419-3b25d923346b h1:sgn3ZU783SCgtaSJjpcVVlRqd6GSnlTLKgpAAttJvpI=
+k8s.io/utils v0.0.0-20230726121419-3b25d923346b/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 rsc.io/binaryregexp v0.2.0/go.mod h1:qTv7/COck+e2FymRvadv62gMdZztPaShugOCi3I+8D8=
 sigs.k8s.io/cluster-api v1.5.1 h1:+oO4EbVQcbBJr5wjqmdjvewPHSTbVLigXZqPk3ZO8t0=
 sigs.k8s.io/cluster-api v1.5.1/go.mod h1:EGJUNpFWi7dF426tO8MG/jE+w7T0UO5KyMnOwQ5riUY=
diff --git a/pkg/handlers/auditpolicy/inject.go b/pkg/handlers/auditpolicy/inject.go
index a2ed10e6f..1618d86c5 100644
--- a/pkg/handlers/auditpolicy/inject.go
+++ b/pkg/handlers/auditpolicy/inject.go
@@ -18,6 +18,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches/selectors"
 )
@@ -32,8 +33,8 @@ type auditPolicyPatchHandler struct {
 }
 
 var (
-	_ handlers.NamedHandler                   = &auditPolicyPatchHandler{}
-	_ handlers.GeneratePatchesMutationHandler = &auditPolicyPatchHandler{}
+	_ handlers.Named           = &auditPolicyPatchHandler{}
+	_ mutation.GeneratePatches = &auditPolicyPatchHandler{}
 
 	//go:embed embedded/apiserver-audit-policy.yaml
 	auditPolicy string
diff --git a/pkg/handlers/cni/calico/handler.go b/pkg/handlers/cni/calico/handler.go
index 335109d46..269605f1c 100644
--- a/pkg/handlers/cni/calico/handler.go
+++ b/pkg/handlers/cni/calico/handler.go
@@ -24,6 +24,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/lifecycle"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/handlers/cni"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/k8s/client"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/k8s/parser"
@@ -70,8 +71,8 @@ type CalicoCNI struct {
 }
 
 var (
-	_ handlers.NamedHandler                                 = &CalicoCNI{}
-	_ handlers.AfterControlPlaneInitializedLifecycleHandler = &CalicoCNI{}
+	_ handlers.Named                         = &CalicoCNI{}
+	_ lifecycle.AfterControlPlaneInitialized = &CalicoCNI{}
 
 	calicoInstallationGK = schema.GroupKind{Group: "operator.tigera.io", Kind: "Installation"}
 )
diff --git a/pkg/handlers/extraapiservercertsans/inject.go b/pkg/handlers/extraapiservercertsans/inject.go
index 5d3350020..84fba2548 100644
--- a/pkg/handlers/extraapiservercertsans/inject.go
+++ b/pkg/handlers/extraapiservercertsans/inject.go
@@ -18,6 +18,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches/selectors"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/variables"
@@ -33,8 +34,8 @@ type extraAPIServerCertSANsPatchHandler struct {
 }
 
 var (
-	_ handlers.NamedHandler                   = &extraAPIServerCertSANsPatchHandler{}
-	_ handlers.GeneratePatchesMutationHandler = &extraAPIServerCertSANsPatchHandler{}
+	_ handlers.Named           = &extraAPIServerCertSANsPatchHandler{}
+	_ mutation.GeneratePatches = &extraAPIServerCertSANsPatchHandler{}
 )
 
 func NewPatch() *extraAPIServerCertSANsPatchHandler {
diff --git a/pkg/handlers/extraapiservercertsans/variables.go b/pkg/handlers/extraapiservercertsans/variables.go
index 05d748953..c5cf8fe45 100644
--- a/pkg/handlers/extraapiservercertsans/variables.go
+++ b/pkg/handlers/extraapiservercertsans/variables.go
@@ -10,12 +10,13 @@ import (
 	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/openapi/patterns"
 )
 
 var (
-	_ handlers.NamedHandler                     = &extraAPIServerCertSANsVariableHandler{}
-	_ handlers.DiscoverVariablesMutationHandler = &extraAPIServerCertSANsVariableHandler{}
+	_ handlers.Named             = &extraAPIServerCertSANsVariableHandler{}
+	_ mutation.DiscoverVariables = &extraAPIServerCertSANsVariableHandler{}
 )
 
 const (
diff --git a/pkg/handlers/extraapiservercertsans/variables_test.go b/pkg/handlers/extraapiservercertsans/variables_test.go
index 3881cbe4b..e054a32a4 100644
--- a/pkg/handlers/extraapiservercertsans/variables_test.go
+++ b/pkg/handlers/extraapiservercertsans/variables_test.go
@@ -4,82 +4,32 @@
 package extraapiservercertsans
 
 import (
-	"context"
-	"encoding/json"
 	"testing"
 
-	. "github.com/onsi/gomega"
-	. "github.com/onsi/gomega/gstruct"
-	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
-	"k8s.io/apimachinery/pkg/util/validation/field"
-	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
-	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
+	"k8s.io/utils/ptr"
 
-	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/testutils/openapi"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/testutils/capitest"
 )
 
-func TestVariableValidation_extraAPIServerCertSANs(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name        string
-		vals        []string
-		expectError bool
-	}{{
-		name: "single valid SAN",
-		vals: []string{"a.b.c.example.com"},
-	}, {
-		name:        "single invalid SAN",
-		vals:        []string{"invalid:san"},
-		expectError: true,
-	}, {
-		name:        "duplicate valid SANs",
-		vals:        []string{"a.b.c.example.com", "a.b.c.example.com"},
-		expectError: true,
-	}}
-
-	for idx := range tests {
-		tt := tests[idx]
-
-		t.Run(tt.name, func(t *testing.T) {
-			t.Parallel()
-
-			g := NewWithT(t)
-			h := NewVariable()
-			resp := &runtimehooksv1.DiscoverVariablesResponse{}
-			h.DiscoverVariables(
-				context.Background(),
-				&runtimehooksv1.DiscoverVariablesRequest{},
-				resp,
-			)
-
-			g.Expect(resp.Status).To(Equal(runtimehooksv1.ResponseStatusSuccess))
-			g.Expect(resp.Variables).To(HaveLen(1))
-
-			variable := resp.Variables[0]
-			g.Expect(variable).To(MatchFields(IgnoreExtras, Fields{
-				"Name":     Equal(VariableName),
-				"Required": BeFalse(),
-				"Schema":   Equal(ExtraAPIServerCertSANsVariables{}.VariableSchema()),
-			}))
-
-			encodedVals, err := json.Marshal(tt.vals)
-			g.Expect(err).NotTo(HaveOccurred())
-
-			validateErr := openapi.ValidateClusterVariable(
-				&clusterv1.ClusterVariable{
-					Name:  VariableName,
-					Value: apiextensionsv1.JSON{Raw: encodedVals},
-				},
-				&variable,
-				field.NewPath(VariableName),
-			).ToAggregate()
-
-			if tt.expectError {
-				g.Expect(validateErr).To(HaveOccurred())
-			} else {
-				g.Expect(validateErr).NotTo(HaveOccurred())
-			}
-		})
-	}
+func TestVariableValidation(t *testing.T) {
+	capitest.ValidateVariable(
+		t,
+		VariableName,
+		ptr.To(ExtraAPIServerCertSANsVariables{}.VariableSchema()),
+		NewVariable,
+		capitest.VariableTestDef{
+			Name: "single valid SAN",
+			Vals: []string{"a.b.c.example.com"},
+		},
+		capitest.VariableTestDef{
+			Name:        "single invalid SAN",
+			Vals:        []string{"invalid:san"},
+			ExpectError: true,
+		},
+		capitest.VariableTestDef{
+			Name:        "duplicate valid SANs",
+			Vals:        []string{"a.b.c.example.com", "a.b.c.example.com"},
+			ExpectError: true,
+		},
+	)
 }
diff --git a/pkg/handlers/httpproxy/inject.go b/pkg/handlers/httpproxy/inject.go
index c164330c2..55a90f701 100644
--- a/pkg/handlers/httpproxy/inject.go
+++ b/pkg/handlers/httpproxy/inject.go
@@ -17,6 +17,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/patches/selectors"
 	"github.com/d2iq-labs/capi-runtime-extensions/pkg/capi/clustertopology/variables"
@@ -32,8 +33,8 @@ type httpProxyPatchHandler struct {
 }
 
 var (
-	_ handlers.NamedHandler                   = &httpProxyPatchHandler{}
-	_ handlers.GeneratePatchesMutationHandler = &httpProxyPatchHandler{}
+	_ handlers.Named           = &httpProxyPatchHandler{}
+	_ mutation.GeneratePatches = &httpProxyPatchHandler{}
 )
 
 func NewPatch() *httpProxyPatchHandler {
diff --git a/pkg/handlers/httpproxy/inject_test.go b/pkg/handlers/httpproxy/inject_test.go
index 5937a7b8e..906465959 100644
--- a/pkg/handlers/httpproxy/inject_test.go
+++ b/pkg/handlers/httpproxy/inject_test.go
@@ -40,7 +40,7 @@ func TestGeneratePatches_KubeadmControlPlaneTemplate(t *testing.T) {
 			newVariable(httpproxy.VariableName, httpproxy.HTTPProxyVariables{
 				HTTP:  "http://example.com",
 				HTTPS: "https://example.com",
-				NO:    []string{"https://no-proxy.example.com"},
+				No:    []string{"https://no-proxy.example.com"},
 			}),
 		},
 		Items: []runtimehooksv1.GeneratePatchesRequestItem{
@@ -90,7 +90,7 @@ func TestGeneratePatches_KubeadmConfigTemplate(t *testing.T) {
 			newVariable(httpproxy.VariableName, httpproxy.HTTPProxyVariables{
 				HTTP:  "http://example.com",
 				HTTPS: "https://example.com",
-				NO:    []string{"https://no-proxy.example.com"},
+				No:    []string{"https://no-proxy.example.com"},
 			}),
 			newVariable("builtin", map[string]any{
 				"machineDeployment": map[string]any{
diff --git a/pkg/handlers/httpproxy/systemd_proxy_config.go b/pkg/handlers/httpproxy/systemd_proxy_config.go
index a6054793a..dbb612861 100644
--- a/pkg/handlers/httpproxy/systemd_proxy_config.go
+++ b/pkg/handlers/httpproxy/systemd_proxy_config.go
@@ -27,7 +27,7 @@ var (
 )
 
 func generateSystemdFiles(vars HTTPProxyVariables) []bootstrapv1.File {
-	if vars.HTTP == "" && vars.HTTPS == "" && len(vars.NO) == 0 {
+	if vars.HTTP == "" && vars.HTTPS == "" && len(vars.No) == 0 {
 		return nil
 	}
 
@@ -38,7 +38,7 @@ func generateSystemdFiles(vars HTTPProxyVariables) []bootstrapv1.File {
 	}{
 		HTTP:  vars.HTTP,
 		HTTPS: vars.HTTPS,
-		NO:    strings.Join(vars.NO, ","),
+		NO:    strings.Join(vars.No, ","),
 	}
 
 	var buf bytes.Buffer
diff --git a/pkg/handlers/httpproxy/systemd_proxy_config_test.go b/pkg/handlers/httpproxy/systemd_proxy_config_test.go
index 6c2361eb8..158b2dc0f 100644
--- a/pkg/handlers/httpproxy/systemd_proxy_config_test.go
+++ b/pkg/handlers/httpproxy/systemd_proxy_config_test.go
@@ -24,7 +24,7 @@ func TestGenerateSystemdFiles(t *testing.T) {
 		vars: HTTPProxyVariables{
 			HTTP:  "http://example.com",
 			HTTPS: "https://example.com",
-			NO: []string{
+			No: []string{
 				"https://no-proxy.example.com",
 			},
 		},
@@ -57,7 +57,7 @@ Environment="https_proxy=https://example.com"
 	}, {
 		name: "no proxy only",
 		vars: HTTPProxyVariables{
-			NO: []string{
+			No: []string{
 				"https://no-proxy.example.com",
 			},
 		},
@@ -68,7 +68,7 @@ Environment="no_proxy=https://no-proxy.example.com"
 	}, {
 		name: "multiple no proxy only",
 		vars: HTTPProxyVariables{
-			NO: []string{
+			No: []string{
 				"https://no-proxy.example.com",
 				"https://no-proxy-1.example.com",
 			},
diff --git a/pkg/handlers/httpproxy/variables.go b/pkg/handlers/httpproxy/variables.go
index cf5ed7ed0..2f0cf28bf 100644
--- a/pkg/handlers/httpproxy/variables.go
+++ b/pkg/handlers/httpproxy/variables.go
@@ -10,11 +10,12 @@ import (
 	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/mutation"
 )
 
 var (
-	_ handlers.NamedHandler                     = &httpProxyVariableHandler{}
-	_ handlers.DiscoverVariablesMutationHandler = &httpProxyVariableHandler{}
+	_ handlers.Named             = &httpProxyVariableHandler{}
+	_ mutation.DiscoverVariables = &httpProxyVariableHandler{}
 )
 
 const (
@@ -52,13 +53,13 @@ func (h *httpProxyVariableHandler) DiscoverVariables(
 // HTTPProxyVariables required for providing proxy configuration.
 type HTTPProxyVariables struct {
 	// HTTP proxy.
-	HTTP string `json:"http"`
+	HTTP string `json:"http,omitempty"`
 
 	// HTTPS proxy.
-	HTTPS string `json:"https"`
+	HTTPS string `json:"https,omitempty"`
 
 	// No Proxy list.
-	NO []string `json:"no"`
+	No []string `json:"no,omitempty"`
 }
 
 // VariableSchema provides Cluster Class variable schema definition.
diff --git a/pkg/handlers/httpproxy/variables_test.go b/pkg/handlers/httpproxy/variables_test.go
index fc16ffc28..7bf0b4c14 100644
--- a/pkg/handlers/httpproxy/variables_test.go
+++ b/pkg/handlers/httpproxy/variables_test.go
@@ -1,32 +1,29 @@
 // Copyright 2023 D2iQ, Inc. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-package httpproxy_test
+package httpproxy
 
 import (
-	"context"
 	"testing"
 
-	. "github.com/onsi/gomega"
-	. "github.com/onsi/gomega/gstruct"
-	runtimehooksv1 "sigs.k8s.io/cluster-api/exp/runtime/hooks/api/v1alpha1"
+	"k8s.io/utils/ptr"
 
-	"github.com/d2iq-labs/capi-runtime-extensions/pkg/handlers/httpproxy"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/testutils/capitest"
 )
 
-func TestDiscoverVariables(t *testing.T) {
-	g := NewWithT(t)
-	h := httpproxy.NewVariable()
-	resp := &runtimehooksv1.DiscoverVariablesResponse{}
-	h.DiscoverVariables(context.Background(), &runtimehooksv1.DiscoverVariablesRequest{}, resp)
-
-	g.Expect(resp.Status).To(Equal(runtimehooksv1.ResponseStatusSuccess))
-	g.Expect(resp.Variables).To(HaveLen(1))
-
-	variable := resp.Variables[0]
-	g.Expect(variable).To(MatchFields(IgnoreExtras, Fields{
-		"Name":     Equal(httpproxy.VariableName),
-		"Required": BeFalse(),
-		"Schema":   Equal(httpproxy.HTTPProxyVariables{}.VariableSchema()),
-	}))
+func TestVariableValidation(t *testing.T) {
+	capitest.ValidateVariable(
+		t,
+		VariableName,
+		ptr.To(HTTPProxyVariables{}.VariableSchema()),
+		NewVariable,
+		capitest.VariableTestDef{
+			Name: "valid values",
+			Vals: HTTPProxyVariables{
+				HTTP:  "http://a.b.c.example.com",
+				HTTPS: "https://a.b.c.example.com",
+				No:    []string{"d.e.f.example.com"},
+			},
+		},
+	)
 }
diff --git a/pkg/handlers/servicelbgc/handler.go b/pkg/handlers/servicelbgc/handler.go
index bf5c8e20d..c4dbc81db 100644
--- a/pkg/handlers/servicelbgc/handler.go
+++ b/pkg/handlers/servicelbgc/handler.go
@@ -14,6 +14,7 @@ import (
 	ctrlclient "sigs.k8s.io/controller-runtime/pkg/client"
 
 	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers"
+	"github.com/d2iq-labs/capi-runtime-extensions/common/pkg/handlers/lifecycle"
 )
 
 type ServiceLoadBalancerGC struct {
@@ -21,8 +22,8 @@ type ServiceLoadBalancerGC struct {
 }
 
 var (
-	_ handlers.NamedHandler                        = &ServiceLoadBalancerGC{}
-	_ handlers.BeforeClusterDeleteLifecycleHandler = &ServiceLoadBalancerGC{}
+	_ handlers.Named                = &ServiceLoadBalancerGC{}
+	_ lifecycle.BeforeClusterDelete = &ServiceLoadBalancerGC{}
 )
 
 func New(client ctrlclient.Client) *ServiceLoadBalancerGC {