--- title: Create an External Load Balancer content_type: task weight: 80 --- This page shows how to create an external load balancer. When creating a {{< glossary_tooltip text="Service" term_id="service" >}}, you have the option of automatically creating a cloud 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_. You can also use an {{< glossary_tooltip term_id="ingress" >}} in place of Service. For more information, check the [Ingress](/docs/concepts/services-networking/ingress/) documentation. ## {{% heading "prerequisites" %}} {{< include "task-tutorial-prereqs.md" >}} Your cluster must be running in a cloud or other environment that already has support for configuring external load balancers. ## Create a Service ### Create a Service from a manifest To create an external load balancer, add the following line to your Service manifest: ```yaml type: LoadBalancer ``` Your manifest might then look like: ```yaml apiVersion: v1 kind: Service metadata: name: example-service spec: selector: app: example ports: - port: 8765 targetPort: 9376 type: LoadBalancer ``` ### Create a Service using kubectl You can alternatively create the service with the `kubectl expose` command and its `--type=LoadBalancer` flag: ```bash kubectl expose deployment 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 {{< glossary_tooltip text="Deployment" term_id="deployment" >}} 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 similar to: ``` Name: example-service Namespace: default Labels: app=example Annotations: Selector: app=example Type: LoadBalancer IP Families: IP: 10.3.22.96 IPs: 10.3.22.96 LoadBalancer Ingress: 192.0.2.89 Port: 8765/TCP TargetPort: 9376/TCP NodePort: 30593/TCP Endpoints: 172.17.0.3:9376 Session Affinity: None External Traffic Policy: Cluster Events: ``` The load balancer's 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: ```bash minikube service example-service --url ``` {{< /note >}} ## Preserving the client source IP By default, 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 `.spec` of the 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. * `.spec.healthCheckNodePort` - specifies the health check node port (numeric port number) for the service. If you don't specify `healthCheckNodePort`, 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`. The Service will use the user-specified `healthCheckNodePort` value if you specify it, provided that the Service `type` is set to LoadBalancer and `externalTrafficPolicy` is set to `Local`. Setting `externalTrafficPolicy` to Local in the Service manifest activates this feature. For example: ```yaml apiVersion: v1 kind: Service metadata: name: example-service spec: selector: app: example ports: - port: 8765 targetPort: 9376 externalTrafficPolicy: Local type: LoadBalancer ``` ### Caveats and limitations when preserving source IPs Load balancing services from some cloud providers do not let you configure different weights for each target. With each target weighted equally in terms of sending traffic to Nodes, external traffic is not equally load balanced across different Pods. The external load balancer is unaware of the number of Pods on each node that are used as a target. Where `NumServicePods << NumNodes` or `NumServicePods >> NumNodes`, a fairly close-to-equal distribution will be seen, even without weights. Internal pod to pod traffic should behave similar to ClusterIP services, with equal probability across all pods. ## 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 nodes hosting the relevant Kubernetes pods. The Kubernetes control plane automates the creation of the external load balancer, health checks (if needed), and packet filtering rules (if needed). Once the cloud provider allocates an IP address for the load balancer, the control plane looks up that external IP address and populates it into the Service object. ## {{% heading "whatsnext" %}} * Follow the [Connecting Applications with Services](/docs/tutorials/services/connect-applications-service/) tutorial * Read about [Service](/docs/concepts/services-networking/service/) * Read about [Ingress](/docs/concepts/services-networking/ingress/)