2016-10-15 22:04:23 +00:00
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---
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2016-12-15 20:16:54 +00:00
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title: Exposing an External IP Address to Access an Application in a Cluster
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2016-10-15 22:04:23 +00:00
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---
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{% capture overview %}
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2016-12-22 09:14:39 +00:00
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This page shows how to create a Kubernetes Service object that exposes an
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2016-10-15 22:04:23 +00:00
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external IP address.
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{% endcapture %}
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{% capture prerequisites %}
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2017-03-16 21:53:31 +00:00
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* Install [kubectl](http://kubernetes.io/docs/tasks/kubectl/install/).
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2016-12-20 22:11:35 +00:00
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* Use a cloud provider like Google Container Engine or Amazon Web Services to
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create a Kubernetes cluster. This tutorial creates an
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[external load balancer](/docs/user-guide/load-balancer/),
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which requires a cloud provider.
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* Configure `kubectl` to communicate with your Kubernetes API server. For
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instructions, see the documentation for your cloud provider.
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2016-10-15 22:04:23 +00:00
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{% endcapture %}
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{% capture objectives %}
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* Run five instances of a Hello World application.
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* Create a Service object that exposes an external IP address.
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* Use the Service object to access the running application.
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{% endcapture %}
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{% capture lessoncontent %}
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2017-01-18 18:18:37 +00:00
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## Creating a service for an application running in five pods
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2016-10-15 22:04:23 +00:00
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1. Run a Hello World application in your cluster:
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kubectl run hello-world --replicas=5 --labels="run=load-balancer-example" --image=gcr.io/google-samples/node-hello:1.0 --port=8080
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The preceding command creates a
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[Deployment](/docs/user-guide/deployments/)
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object and an associated
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[ReplicaSet](/docs/user-guide/replicasets/)
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object. The ReplicaSet has five
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[Pods](/docs/user-guide/pods/),
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each of which runs the Hello World application.
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1. Display information about the Deployment:
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kubectl get deployments hello-world
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kubectl describe deployments hello-world
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1. Display information about your ReplicaSet objects:
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kubectl get replicasets
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kubectl describe replicasets
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1. Create a Service object that exposes the deployment:
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kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
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1. Display information about the Service:
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kubectl get services my-service
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The output is similar to this:
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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my-service 10.3.245.137 104.198.205.71 8080/TCP 54s
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2016-12-06 09:12:23 +00:00
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Note: If the external IP address is shown as \<pending\>, wait for a minute
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2016-10-15 22:04:23 +00:00
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and enter the same command again.
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1. Display detailed information about the Service:
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kubectl describe services my-service
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The output is similar to this:
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Name: my-service
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Namespace: default
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Labels: run=load-balancer-example
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Selector: run=load-balancer-example
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Type: LoadBalancer
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IP: 10.3.245.137
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LoadBalancer Ingress: 104.198.205.71
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Port: <unset> 8080/TCP
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NodePort: <unset> 32377/TCP
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Endpoints: 10.0.0.6:8080,10.0.1.6:8080,10.0.1.7:8080 + 2 more...
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Session Affinity: None
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Events:
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Make a note of the external IP address exposed by your service. In this
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example, the external IP address is 104.198.205.71. Also note
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the value of Port. In this example, the port is 8080.
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1. In the preceding output, you can see that the service has several endpoints:
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10.0.0.6:8080,10.0.1.6:8080,10.0.1.7:8080 + 2 more. These are internal
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addresses of the pods that are running the Hello World application. To
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verify these are pod addresses, enter this command:
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kubectl get pods --output=wide
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The output is similar to this:
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NAME ... IP NODE
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hello-world-2895499144-1jaz9 ... 10.0.1.6 gke-cluster-1-default-pool-e0b8d269-1afc
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hello-world-2895499144-2e5uh ... 0.0.1.8 gke-cluster-1-default-pool-e0b8d269-1afc
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hello-world-2895499144-9m4h1 ... 10.0.0.6 gke-cluster-1-default-pool-e0b8d269-5v7a
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hello-world-2895499144-o4z13 ... 10.0.1.7 gke-cluster-1-default-pool-e0b8d269-1afc
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hello-world-2895499144-segjf ... 10.0.2.5 gke-cluster-1-default-pool-e0b8d269-cpuc
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1. Use the external IP address to access the Hello World application:
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curl http://<external-ip>:<port>
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2016-12-06 09:12:23 +00:00
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where `<external-ip>` is the external IP address of your Service,
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2016-10-15 22:04:23 +00:00
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and `<port>` is the value of `Port` in your Service description.
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The response to a successful request is a hello message:
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Hello Kubernetes!
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{% endcapture %}
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{% capture cleanup %}
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To delete the Service, enter this command:
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kubectl delete services my-service
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To delete the Deployment, the ReplicaSet, and the Pods that are running
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the Hello World application, enter this command:
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kubectl delete deployment hello-world
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{% endcapture %}
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{% capture whatsnext %}
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Learn more about
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[connecting applications with services](/docs/user-guide/connecting-applications/).
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{% endcapture %}
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{% include templates/tutorial.md %}
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