rfc: IGP resource, controller, and provider

Add a Custom Resource for Interior Gateway Protocol (IGP) spec. While we
plan support for ISIS and OSPF, we consider only ISIS here.  We also include
a `cisco-nxos-gnmi` provider with an `isis` pkg to configure ISIS over
gNMI using ygot objects from openconfig. This provider does not
implement yet the `interface` resource.

Both the resource and the provider implementation DO NOT support
multiple IGP processes on the same device.

Author: nikatza

Tiltfile

@@ -37,6 +37,9 @@ k8s_resource(new_name='eth1-1', objects=['eth1-1:interface'], trigger_mode=TRIGG
 k8s_resource(new_name='eth1-2', objects=['eth1-2:interface'], trigger_mode=TRIGGER_MODE_MANUAL, auto_init=False)
 k8s_resource(new_name='eth1-10', objects=['eth1-10:interface'], trigger_mode=TRIGGER_MODE_MANUAL, auto_init=False)
 
+k8s_yaml('./config/samples/v1alpha1_igp.yaml')
+k8s_resource(new_name='leaf1-underlay-isis', objects=['leaf1-underlay-isis:igp'], trigger_mode=TRIGGER_MODE_MANUAL, auto_init=False)
+
 print('🚀 network-operator development environment')
 print('👉 Edit the code inside the api/, cmd/, or internal/ directories')
 print('👉 Tilt will automatically rebuild and redeploy when changes are detected')

api/v1alpha1/igp_types.go

@@ -0,0 +1,108 @@
+// SPDX-FileCopyrightText: 2025 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: Apache-2.0
+
+package v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// +kubebuilder:validation:Enum=ISIS
+type IGPType string
+
+// IGProcessSpec defines the desired state of Interior Gateway Protocol (IGP) process on a device.
+type IGPSpec struct {
+	// The name of the routing instance.
+	//+kubebuilder:validation:Required
+	Name string `json:"name"`
+	//+kubebuilder:validation:Required
+	ISIS ISISSpec `json:"isis,omitempty"`
+}
+
+// +kubebuilder:validation:Enum=Level1;Level2;Level12
+type ISISLevel string
+
+const (
+	Level1  ISISLevel = "Level1"
+	Level2  ISISLevel = "Level2"
+	Level12 ISISLevel = "Level12"
+)
+
+// +kubebuilder:validation:Enum=IPv4Unicast;IPv6Unicast
+type ISISAF string
+
+const (
+	IPv4Unicast ISISAF = "IPv4Unicast"
+	IPv6Unicast ISISAF = "IPv6Unicast"
+)
+
+type OverloadBit struct {
+	// Duration of the OverloadBit in seconds.
+	//+kubebuilder:validation:Required
+	//+kubebuilder:validation:Minimum=576
+	//+kubebuilder:validation:Maximum=86400
+	OnStartup uint32 `json:"onStartup"`
+}
+
+type ISISSpec struct {
+	// The Network Entity Title (NET) for the ISIS instance.
+	//+kubebuilder:validation:Required
+	NET string `json:"net"`
+	// The is-type of the process (the level)
+	//+kubebuilder:validation:Required
+	Level ISISLevel `json:"level"`
+	// Overload bit configuration for this ISIS instance
+	//+kubebuilder:validation:Optional
+	OverloadBit *OverloadBit `json:"overloadBit"`
+	//+kubebuilder:validation:Required
+	//+kubebuilder:validation:MinItems=1
+	//+kubebuilder:validation:MaxItems=2
+	AddressFamilies []ISISAF `json:"addressFamilies,omitempty"`
+}
+
+// IGPStatus defines the observed state of an IGP process.
+type IGPStatus struct {
+	// The conditions are a list of status objects that describe the state of the Interface.
+	//+listType=map
+	//+listMapKey=type
+	//+patchStrategy=merge
+	//+patchMergeKey=type
+	//+optional
+	Conditions []metav1.Condition `json:"conditions,omitempty" patchStrategy:"merge" patchMergeKey:"type"`
+}
+
+// +kubebuilder:object:root=true
+// +kubebuilder:subresource:status
+// +kubebuilder:resource:path=igps
+// +kubebuilder:resource:singular=igp
+// +kubebuilder:resource:shortName=igp
+// +kubebuilder:printcolumn:name="Process name",type=string,JSONPath=`.spec.name`
+// +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp"
+
+// IGP is the Schema for the igp API.
+type IGP struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	// Specification of the desired state of the resource.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
+	Spec IGPSpec `json:"spec,omitempty"`
+
+	// Status of the resource. This is set and updated automatically.
+	// Read-only.
+	// More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
+	Status IGPStatus `json:"status,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+
+// IGPList contains a list of IGP (processes).
+type IGPList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata,omitempty"`
+	Items           []IGP `json:"items"`
+}
+
+func init() {
+	SchemeBuilder.Register(&IGP{}, &IGPList{})
+}