Add Gzip Compression Option for User Data

bootstrap/api/v1alpha1/conversion.go

@@ -51,6 +51,10 @@ func (src *RKE2Config) ConvertTo(dstRaw conversion.Hub) error {
 		dst.Spec.AgentConfig.PodSecurityAdmissionConfigFile = restored.Spec.AgentConfig.PodSecurityAdmissionConfigFile
 	}
 
+	if restored.Spec.GzipUserData != nil {
+		dst.Spec.GzipUserData = restored.Spec.GzipUserData
+	}
+
 	return nil
 }
 
@@ -110,6 +114,10 @@ func (src *RKE2ConfigTemplate) ConvertTo(dstRaw conversion.Hub) error {
 		dst.Spec.Template.Spec.AgentConfig.PodSecurityAdmissionConfigFile = restored.Spec.Template.Spec.AgentConfig.PodSecurityAdmissionConfigFile
 	}
 
+	if restored.Spec.Template.Spec.GzipUserData != nil {
+		dst.Spec.Template.Spec.GzipUserData = restored.Spec.Template.Spec.GzipUserData
+	}
+
 	return nil
 }
 
@@ -154,3 +162,22 @@ func Convert_v1beta1_RKE2AgentConfig_To_v1alpha1_RKE2AgentConfig(in *bootstrapv1
 	// We have to invoke conversion manually because of the added AirGappedChecksum field.
 	return autoConvert_v1beta1_RKE2AgentConfig_To_v1alpha1_RKE2AgentConfig(in, out, s)
 }
+
+func Convert_v1alpha1_RKE2ConfigSpec_To_v1beta1_RKE2ConfigSpec(in *RKE2ConfigSpec, out *bootstrapv1.RKE2ConfigSpec, s apiconversion.Scope) error {
+	if err := autoConvert_v1alpha1_RKE2ConfigSpec_To_v1beta1_RKE2ConfigSpec(in, out, s); err != nil {
+		return err
+	}
+
+	// Default to false during up-conversion since field doesn't exist in v1alpha1
+	out.GzipUserData = nil
+	return nil
+}
+
+func Convert_v1beta1_RKE2ConfigSpec_To_v1alpha1_RKE2ConfigSpec(in *bootstrapv1.RKE2ConfigSpec, out *RKE2ConfigSpec, s apiconversion.Scope) error {
+	if err := autoConvert_v1beta1_RKE2ConfigSpec_To_v1alpha1_RKE2ConfigSpec(in, out, s); err != nil {
+		return err
+	}
+
+	// GzipUserData does not exist in v1alpha1, so it's intentionally ignored
+	return nil
+}

bootstrap/api/v1alpha1/conversion_test.go

@@ -37,17 +37,23 @@ func TestFuzzyConversion(t *testing.T) {
 	g.Expect(bootstrapv1.AddToScheme(scheme)).To(Succeed())
 
 	t.Run("for RKE2Config", utilconversion.FuzzTestFunc(utilconversion.FuzzTestFuncInput{
-		Scheme:      scheme,
-		Hub:         &bootstrapv1.RKE2Config{},
-		Spoke:       &RKE2Config{},
-		FuzzerFuncs: []fuzzer.FuzzerFuncs{fuzzFuncs},
+		Scheme: scheme,
+		Hub:    &bootstrapv1.RKE2Config{},
+		Spoke:  &RKE2Config{},
+		FuzzerFuncs: []fuzzer.FuzzerFuncs{
+			fuzzFuncs,                    // v1alpha1 fuzzer
+			bootstrapv1.FuzzFuncsv1beta1, // v1beta1 fuzzer
+		},
 	}))
 
 	t.Run("for RKE2ConfigTemplate", utilconversion.FuzzTestFunc(utilconversion.FuzzTestFuncInput{
-		Scheme:      scheme,
-		Hub:         &bootstrapv1.RKE2ConfigTemplate{},
-		Spoke:       &RKE2ConfigTemplate{},
-		FuzzerFuncs: []fuzzer.FuzzerFuncs{fuzzFuncs},
+		Scheme: scheme,
+		Hub:    &bootstrapv1.RKE2ConfigTemplate{},
+		Spoke:  &RKE2ConfigTemplate{},
+		FuzzerFuncs: []fuzzer.FuzzerFuncs{
+			fuzzFuncs,
+			bootstrapv1.FuzzFuncsv1beta1,
+		},
 	}))
 }
 

bootstrap/api/v1beta1/fuzzer.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2025 SUSE LLC.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1beta1
+
+import (
+	fuzz "github.com/google/gofuzz"
+	runtimeserializer "k8s.io/apimachinery/pkg/runtime/serializer"
+)
+
+// FuzzFuncsv1beta1 exposes fuzzers for testing conversion logic.
+func FuzzFuncsv1beta1(_ runtimeserializer.CodecFactory) []interface{} {
+	return []interface{}{
+		RKE2ConfigFuzzer,
+		RKE2ConfigTemplateFuzzer,
+	}
+}
+
+// RKE2ConfigFuzzer is fuzzer for v1beta1 RKE2Config (hub).
+func RKE2ConfigFuzzer(obj *RKE2Config, c fuzz.Continue) {
+	c.FuzzNoCustom(obj)
+	val := c.RandBool()
+	obj.Spec.GzipUserData = &val
+}
+
+// RKE2ConfigTemplateFuzzer is fuzzer for v1beta1 RKE2ConfigTemplate (hub).
+func RKE2ConfigTemplateFuzzer(obj *RKE2ConfigTemplate, c fuzz.Continue) {
+	c.FuzzNoCustom(obj)
+	val := c.RandBool()
+	obj.Spec.Template.Spec.GzipUserData = &val
+}

bootstrap/api/v1beta1/rke2config_types.go

@@ -56,6 +56,10 @@ type RKE2ConfigSpec struct {
 	// PrivateRegistriesConfig defines the containerd configuration for private registries and local registry mirrors.
 	//+optional
 	PrivateRegistriesConfig Registry `json:"privateRegistriesConfig,omitempty"`
+
+	// GzipUserData specifies if the user data should be gzipped.
+	//+optional
+	GzipUserData *bool `json:"gzipUserData,omitempty"`
 }
 
 // RKE2AgentConfig describes some attributes that are common to agent and server nodes.

bootstrap/api/v1beta1/rke2config_webhook.go

@@ -84,6 +84,11 @@ func DefaultRKE2ConfigSpec(spec *RKE2ConfigSpec) {
 	if spec.AgentConfig.Format == "" {
 		spec.AgentConfig.Format = CloudConfig
 	}
+
+	if spec.GzipUserData == nil {
+		spec.GzipUserData = new(bool)
+		*spec.GzipUserData = false
+	}
 }
 
 //+kubebuilder:webhook:path=/validate-bootstrap-cluster-x-k8s-io-v1beta1-rke2config,mutating=false,failurePolicy=fail,sideEffects=None,groups=bootstrap.cluster.x-k8s.io,resources=rke2configs,verbs=create;update,versions=v1beta1,name=vrke2config.kb.io,admissionReviewVersions=v1

bootstrap/config/crd/bases/bootstrap.cluster.x-k8s.io_rke2configs.yaml

@@ -952,6 +952,9 @@ spec:
                   - path
                   type: object
                 type: array
+              gzipUserData:
+                description: GzipUserData specifies if the user data should be gzipped.
+                type: boolean
               postRKE2Commands:
                 description: PostRKE2Commands specifies extra commands to run after
                   rke2 setup runs.

bootstrap/config/crd/bases/bootstrap.cluster.x-k8s.io_rke2configtemplates.yaml

@@ -936,6 +936,10 @@ spec:
                           - path
                           type: object
                         type: array
+                      gzipUserData:
+                        description: GzipUserData specifies if the user data should
+                          be gzipped.
+                        type: boolean
                       postRKE2Commands:
                         description: PostRKE2Commands specifies extra commands to
                           run after rke2 setup runs.

bootstrap/internal/controllers/rke2config_controller.go

@@ -18,6 +18,7 @@ package controllers
 
 import (
 	"bytes"
+	"compress/gzip"
 	"context"
 	"fmt"
 	"time"
@@ -50,6 +51,7 @@ import (
 	bootstrapv1 "github.com/rancher/cluster-api-provider-rke2/bootstrap/api/v1beta1"
 	"github.com/rancher/cluster-api-provider-rke2/bootstrap/internal/cloudinit"
 	"github.com/rancher/cluster-api-provider-rke2/bootstrap/internal/ignition"
+	"github.com/rancher/cluster-api-provider-rke2/bootstrap/internal/ignition/butane"
 	controlplanev1 "github.com/rancher/cluster-api-provider-rke2/controlplane/api/v1beta1"
 	"github.com/rancher/cluster-api-provider-rke2/pkg/consts"
 	"github.com/rancher/cluster-api-provider-rke2/pkg/locking"
@@ -642,10 +644,6 @@ func (r *RKE2ConfigReconciler) joinControlplane(ctx context.Context, scope *Scop
 		return ctrl.Result{}, fmt.Errorf("unable to marshal config.yaml: %w", err)
 	}
 
-	if err != nil {
-		return ctrl.Result{}, err
-	}
-
 	scope.Logger.Info("Joining Server config marshalled successfully")
 
 	initConfigFile := bootstrapv1.File{
@@ -893,6 +891,30 @@ func (r *RKE2ConfigReconciler) generateAndStoreToken(ctx context.Context, scope
 // storeBootstrapData creates a new secret with the data passed in as input,
 // sets the reference in the configuration status and ready to true.
 func (r *RKE2ConfigReconciler) storeBootstrapData(ctx context.Context, scope *Scope, data []byte) error {
+	if *scope.Config.Spec.GzipUserData {
+		var buf bytes.Buffer
+		gz := gzip.NewWriter(&buf)
+
+		if _, err := gz.Write(data); err != nil {
+			return err
+		}
+
+		if err := gz.Close(); err != nil {
+			return err
+		}
+
+		if scope.Config.Spec.AgentConfig.Format == bootstrapv1.Ignition {
+			res, err := butane.EncapsulateGzippedConfig(buf.Bytes())
+			if err != nil {
+				return err
+			}
+
+			data = res
+		} else {
+			data = buf.Bytes()
+		}
+	}
+
 	secret := &corev1.Secret{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      scope.Config.Name,

bootstrap/internal/ignition/butane/butane.go

@@ -18,6 +18,7 @@ package butane
 
 import (
 	"bytes"
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -280,3 +281,28 @@ func Render(input *cloudinit.BaseUserData, butaneCfg *bootstrapv1.AdditionalUser
 
 	return userData, nil
 }
+
+// EncapsulateGzippedConfig takes a gzipped Ignition config and encapsulates it in an Ignition config with compression.
+func EncapsulateGzippedConfig(gzippedConfig []byte) ([]byte, error) {
+	comp := "gzip"
+	dataSource := "data:text/plain;base64," + base64.StdEncoding.EncodeToString(gzippedConfig)
+
+	encapCfg := ignitionTypes.Config{
+		Ignition: ignitionTypes.Ignition{
+			Version: "3.3.0",
+			Config: ignitionTypes.IgnitionConfig{
+				Replace: ignitionTypes.Resource{
+					Compression: &comp,
+					Source:      &dataSource,
+				},
+			},
+		},
+	}
+
+	cfg, err := json.Marshal(encapCfg)
+	if err != nil {
+		return nil, errors.Wrap(err, "marshaling Ignition config into JSON")
+	}
+
+	return cfg, nil
+}

controlplane/api/v1alpha1/conversion.go

@@ -45,6 +45,10 @@ func (src *RKE2ControlPlane) ConvertTo(dstRaw conversion.Hub) error {
 		return err
 	}
 
+	if restored.Spec.GzipUserData != nil {
+		dst.Spec.GzipUserData = restored.Spec.GzipUserData
+	}
+
 	if restored.Spec.Version != "" {
 		dst.Spec.Version = restored.Spec.Version
 	}

controlplane/config/crd/bases/controlplane.cluster.x-k8s.io_rke2controlplanes.yaml

@@ -1591,6 +1591,9 @@ spec:
                   - path
                   type: object
                 type: array
+              gzipUserData:
+                description: GzipUserData specifies if the user data should be gzipped.
+                type: boolean
               infrastructureRef:
                 description: |-
                   InfrastructureRef is a required reference to a custom resource

controlplane/config/crd/bases/controlplane.cluster.x-k8s.io_rke2controlplanetemplates.yaml

@@ -432,6 +432,10 @@ spec:
                           - path
                           type: object
                         type: array
+                      gzipUserData:
+                        description: GzipUserData specifies if the user data should
+                          be gzipped.
+                        type: boolean
                       infrastructureRef:
                         description: |-
                           InfrastructureRef is a required reference to a custom resource

docs/book/src/02_topics/05_user_data_compression.md

@@ -0,0 +1,21 @@
+## Configuring User Data Compression
+
+## Overview
+Cloud-init user-data can grow significantly in size, especially when many configurations and embedded scripts are used. Some infrastructure providers (e.g., AWS, OpenStack) have strict size limits for user-data, which can lead to provisioning failures. To address this, the gzipUserData field in RKE2ConfigSpec allows optional gzip compression of the user-data payload before it is passed to the infrastructure provider.
+
+This feature helps reduce the size of the cloud-init payload but should only be used when the infrastructure provider supports gzipped user-data. For example, OpenStack typically handles it well, while others like Metal3 may not.
+
+## Using Gzip Compression for User Data
+The `gzipUserData` field in RKE2ConfigSpec allows you to enable gzip compression for the rendered cloud-init user data. 
+By default, `gzipUserData` is set to `false`. When set to `true`, the user-data is gzipped before being passed to the infrastructure provider.
+
+Example:
+
+```yaml
+apiVersion: bootstrap.cluster.x-k8s.io/v1beta1
+kind: RKE2Config
+metadata:
+  name: my-cluster-bootstrap
+spec:
+  gzipUserData: true
+```