--- title: Create an External Load Balancer content_type: task weight: 80 --- This page shows how to create an External Load Balancer. {{< note >}} This feature is only available for cloud providers or environments which support external load balancers. {{< /note >}} When creating a service, you have the option of automatically creating a cloud network load balancer. This provides an externally-accessible IP address that sends traffic to the correct port on your cluster nodes _provided your cluster runs in a supported environment and is configured with the correct cloud load balancer provider package_. For information on provisioning and using an Ingress resource that can give services externally-reachable URLs, load balance the traffic, terminate SSL etc., please check the [Ingress](/docs/concepts/services-networking/ingress/) documentation. ## {{% heading "prerequisites" %}} * {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}} ## Configuration file To create an external load balancer, add the following line to your [service configuration file](/docs/concepts/services-networking/service/#loadbalancer): ```yaml type: LoadBalancer ``` Your configuration file might look like: ```yaml apiVersion: v1 kind: Service metadata: name: example-service spec: selector: app: example ports: - port: 8765 targetPort: 9376 type: LoadBalancer ``` ## Using kubectl You can alternatively create the service with the `kubectl expose` command and its `--type=LoadBalancer` flag: ```bash kubectl expose rc example --port=8765 --target-port=9376 \ --name=example-service --type=LoadBalancer ``` This command creates a new service using the same selectors as the referenced resource (in the case of the example above, a replication controller named `example`). For more information, including optional flags, refer to the [`kubectl expose` reference](/docs/reference/generated/kubectl/kubectl-commands/#expose). ## Finding your IP address You can find the IP address created for your service by getting the service information through `kubectl`: ```bash kubectl describe services example-service ``` which should produce output like this: ```bash Name: example-service Namespace: default Labels: Annotations: Selector: app=example Type: LoadBalancer IP: 10.67.252.103 LoadBalancer Ingress: 192.0.2.89 Port: 80/TCP NodePort: 32445/TCP Endpoints: 10.64.0.4:80,10.64.1.5:80,10.64.2.4:80 Session Affinity: None Events: ``` The IP address is listed next to `LoadBalancer Ingress`. {{< note >}} If you are running your service on Minikube, you can find the assigned IP address and port with: {{< /note >}} ```bash minikube service example-service --url ``` ## Preserving the client source IP Due to the implementation of this feature, the source IP seen in the target container is *not the original source IP* of the client. To enable preservation of the client IP, the following fields can be configured in the service spec (supported in GCE/Google Kubernetes Engine environments): * `service.spec.externalTrafficPolicy` - denotes if this Service desires to route external traffic to node-local or cluster-wide endpoints. There are two available options: Cluster (default) and Local. Cluster obscures the client source IP and may cause a second hop to another node, but should have good overall load-spreading. Local preserves the client source IP and avoids a second hop for LoadBalancer and NodePort type services, but risks potentially imbalanced traffic spreading. * `service.spec.healthCheckNodePort` - specifies the health check node port (numeric port number) for the service. If `healthCheckNodePort` isn't specified, the service controller allocates a port from your cluster's NodePort range. You can configure that range by setting an API server command line option, `--service-node-port-range`. It will use the user-specified `healthCheckNodePort` value if specified by the client. It only has an effect when `type` is set to LoadBalancer and `externalTrafficPolicy` is set to Local. Setting `externalTrafficPolicy` to Local in the Service configuration file activates this feature. ```yaml apiVersion: v1 kind: Service metadata: name: example-service spec: selector: app: example ports: - port: 8765 targetPort: 9376 externalTrafficPolicy: Local type: LoadBalancer ``` ## Garbage Collecting Load Balancers {{< feature-state for_k8s_version="v1.17" state="stable" >}} In usual case, the correlating load balancer resources in cloud provider should be cleaned up soon after a LoadBalancer type Service is deleted. But it is known that there are various corner cases where cloud resources are orphaned after the associated Service is deleted. Finalizer Protection for Service LoadBalancers was introduced to prevent this from happening. By using finalizers, a Service resource will never be deleted until the correlating load balancer resources are also deleted. Specifically, if a Service has `type` LoadBalancer, the service controller will attach a finalizer named `service.kubernetes.io/load-balancer-cleanup`. The finalizer will only be removed after the load balancer resource is cleaned up. This prevents dangling load balancer resources even in corner cases such as the service controller crashing. ## External Load Balancer Providers It is important to note that the datapath for this functionality is provided by a load balancer external to the Kubernetes cluster. When the Service `type` is set to LoadBalancer, Kubernetes provides functionality equivalent to `type` equals ClusterIP to pods within the cluster and extends it by programming the (external to Kubernetes) load balancer with entries for the Kubernetes pods. The Kubernetes service controller automates the creation of the external load balancer, health checks (if needed), firewall rules (if needed) and retrieves the external IP allocated by the cloud provider and populates it in the service object. ## Caveats and Limitations when preserving source IPs GCE/AWS load balancers do not provide weights for their target pools. This was not an issue with the old LB kube-proxy rules which would correctly balance across all endpoints. With the new functionality, the external traffic is not equally load balanced across pods, but rather equally balanced at the node level (because GCE/AWS and other external LB implementations do not have the ability for specifying the weight per node, they balance equally across all target nodes, disregarding the number of pods on each node). We can, however, state that for NumServicePods << NumNodes or NumServicePods >> NumNodes, a fairly close-to-equal distribution will be seen, even without weights. Once the external load balancers provide weights, this functionality can be added to the LB programming path. *Future Work: No support for weights is provided for the 1.4 release, but may be added at a future date* Internal pod to pod traffic should behave similar to ClusterIP services, with equal probability across all pods.