update readme, lint

README.md

@@ -29,7 +29,13 @@ Kubernetes 1.9+
 ## Usage
 
 ### LoadBalancer Services
-Kubernetes Services of type `LoadBalancer` will be served through a [Linode NodeBalancer](https://www.linode.com/nodebalancers) which the Cloud Controller Manager will provision on demand.  For general feature and usage notes, refer to the [Getting Started with Linode NodeBalancers](https://www.linode.com/docs/platform/nodebalancer/getting-started-with-nodebalancers/) guide.
+Kubernetes Services of type `LoadBalancer` will be served through a [Linode NodeBalancer](https://www.linode.com/nodebalancers) by default which the Cloud Controller Manager will provision on demand.
+For general feature and usage notes, refer to the [Getting Started with Linode NodeBalancers](https://www.linode.com/docs/platform/nodebalancer/getting-started-with-nodebalancers/) guide.
+
+#### Using IP Sharing instead of NodeBalancers
+Alternatively, the Linode CCM can integrate with [Cilium's BGP Control Plane](https://docs.cilium.io/en/stable/network/bgp-control-plane/)
+to perform load-balancing via IP sharing on Nodes selected by an existing `CiliumBGPPeeringPolicy` in the cluster. This option does not create a backing NodeBalancer and instead
+provisions a new IP on an ip-holder Nanode to share. See [Shared IP LoadBalancing](#shared-ip-load-balancing).
 
 #### Annotations
 The Linode CCM accepts several annotations which affect the properties of the underlying NodeBalancer deployment.
@@ -58,6 +64,7 @@ Annotation (Suffix) | Values | Default | Description
 `tags` | string | | A comma seperated list of tags to be applied to the createad NodeBalancer instance
 `firewall-id` | string | | An existing Cloud Firewall ID to be attached to the NodeBalancer instance. See [Firewalls](#firewalls).
 `firewall-acl` | string | | The Firewall rules to be applied to the NodeBalancer. Adding this annotation creates a new CCM managed Linode CloudFirewall instance. See [Firewalls](#firewalls).
+`type` | `nodebalancer`, `cilium-bgp` | | The type of load-balancert to use. If unspecified, the type specified in the CCM's `--default-load-balancer` is used for the Service.
 
 #### Deprecated Annotations
 These annotations are deprecated, and will be removed in a future release.
@@ -78,6 +85,22 @@ Key | Values | Default | Description
 `proxy-protocol` | `none`, `v1`, `v2` | `none` | Specifies whether to use a version of Proxy Protocol on the underlying NodeBalancer. Overwrites `default-proxy-protocol`.
 `tls-secret-name` | string | | Specifies a secret to use for TLS. The secret type should be `kubernetes.io/tls`.
 
+#### Shared IP Load-Balancing
+**NOTE:** This feature requires contacting [Customer Support](https://www.linode.com/support/contact/) to enable provisioning additional IPs.
+
+Services of `type: LoadBalancer` can receive an external IP not backed by a NodeBalancer if `--bgp-node-selector` is set on the Linode CCM and either `--default-load-balancer` is set to `cilium-bgp` or the Service has the `service.beta.kubernetes.io/linode-loadbalancer-type` annotation set to `cilium-bgp`. This feature requires the Kubernetes cluster to be using [Cilium](https://cilium.io/) as the CNI with the `bgp-control-plane` feature enabled and a `CiliumBGPPeeringPolicy` applied to the cluster with a node selector specified in the `--bgp-node-selector` flag, e.g.:
+```
+apiVersion: "cilium.io/v2alpha1"
+kind: CiliumBGPPeeringPolicy
+metadata:
+  name: 01-bgp-peering-policy
+spec:
+  nodeSelector:
+    matchLabels:
+      cilium-bgp-peering: "true"
+```
+where the flag would be `--bgp-node-selector=cilium-bgp-peering=true`.
+
 #### Firewalls
 Firewall rules can be applied to the CCM Managed NodeBalancers in two distinct ways.
 

cloud/linode/cilium_loadbalancers_test.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/linode/linode-cloud-controller-manager/cloud/annotations"
 	"net"
 	"testing"
 
@@ -17,6 +16,8 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/kubernetes/fake"
+
+	"github.com/linode/linode-cloud-controller-manager/cloud/annotations"
 )
 
 var (

cloud/linode/cloud.go

@@ -2,13 +2,13 @@ package linode
 
 import (
 	"fmt"
-	"golang.org/x/exp/slices"
 	"io"
 	"os"
 	"sync"
 
 	"github.com/linode/linodego"
 	"github.com/spf13/pflag"
+	"golang.org/x/exp/slices"
 	"k8s.io/client-go/informers"
 	cloudprovider "k8s.io/cloud-provider"