feat(linode): add cloud foundation and LoadBalancer task

Signed-off-by: Moshe Vayner <moshe@vayner.me>

Author: moshevayner

pkg/model/linodemodel/OWNERS

@@ -0,0 +1,5 @@
+# See the OWNERS docs at <https://go.k8s.io/owners>
+
+labels:
+
+- area/provider/linode

pkg/model/linodemodel/api_loadbalancer.go

@@ -0,0 +1,71 @@
+/*
+Copyright 2026 The Kubernetes Authors.
+
+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 linodemodel
+
+import (
+	"fmt"
+
+	"k8s.io/kops/pkg/apis/kops"
+	"k8s.io/kops/pkg/dns"
+	"k8s.io/kops/pkg/wellknownservices"
+	"k8s.io/kops/upup/pkg/fi"
+	cloudlinode "k8s.io/kops/upup/pkg/fi/cloudup/linode"
+	"k8s.io/kops/upup/pkg/fi/cloudup/linodetasks"
+)
+
+// APILoadBalancerModelBuilder builds a Linode (Akamai) load balancer for API access.
+type APILoadBalancerModelBuilder struct {
+	*LinodeModelContext
+	Lifecycle fi.Lifecycle
+}
+
+var _ fi.CloudupModelBuilder = &APILoadBalancerModelBuilder{}
+
+func (b *APILoadBalancerModelBuilder) Build(c *fi.CloudupModelBuilderContext) error {
+	if !b.UseLoadBalancerForAPI() {
+		return nil
+	}
+
+	if len(b.Cluster.Spec.Networking.Subnets) == 0 || b.Cluster.Spec.Networking.Subnets[0].Region == "" {
+		return fmt.Errorf("linode API load balancer requires at least one subnet with a region")
+	}
+
+	lb := &linodetasks.LoadBalancer{
+		Name:      fi.PtrTo("api." + b.ClusterName()),
+		Lifecycle: b.Lifecycle,
+		Region:    fi.PtrTo(b.Cluster.Spec.Networking.Subnets[0].Region),
+		Tags: []string{
+			cloudlinode.BuildLinodeTag(kops.LabelClusterName, b.ClusterName()),
+		},
+		WellKnownServices: []wellknownservices.WellKnownService{wellknownservices.KubeAPIServer},
+	}
+
+	if dns.IsGossipClusterName(b.Cluster.Name) || b.Cluster.UsesPrivateDNS() || b.Cluster.UsesNoneDNS() {
+		lb.WellKnownServices = append(lb.WellKnownServices, wellknownservices.KopsController)
+	}
+
+	c.AddTask(lb)
+
+	backendReconcile := &linodetasks.LoadBalancerBackends{
+		Name:         fi.PtrTo("backends." + fi.ValueOf(lb.Name)),
+		Lifecycle:    b.Lifecycle,
+		LoadBalancer: lb,
+	}
+	c.AddTask(backendReconcile)
+
+	return nil
+}

pkg/model/linodemodel/context.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2026 The Kubernetes Authors.
+
+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 linodemodel
+
+import "k8s.io/kops/pkg/model"
+
+// LinodeModelContext holds shared model context for Linode (Akamai) builders.
+type LinodeModelContext struct {
+	*model.KopsModelContext
+}

upup/pkg/fi/cloudup/linode/api_target.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2026 The Kubernetes Authors.
+
+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 linode
+
+import "k8s.io/kops/upup/pkg/fi"
+
+// APITarget runs cloudup tasks directly against Linode (Akamai) APIs.
+type APITarget struct {
+	Cloud LinodeCloud
+}
+
+var _ fi.CloudupTarget = &APITarget{}
+
+// NewAPITarget builds a Linode (Akamai) target implementation.
+func NewAPITarget(cloud LinodeCloud) *APITarget {
+	return &APITarget{Cloud: cloud}
+}
+
+func (t *APITarget) Finish(taskMap map[string]fi.CloudupTask) error {
+	return nil
+}
+
+func (t *APITarget) DefaultCheckExisting() bool {
+	return true
+}