From dead30958f355d4e52bb15d55362c34ef0614258 Mon Sep 17 00:00:00 2001 From: Stewart-YU Date: Tue, 15 Aug 2017 01:47:18 +0800 Subject: [PATCH] Update expose-intro.html (#4859) delete "Enter Services.". This may be a mistake. --- docs/tutorials/kubernetes-basics/expose-intro.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/tutorials/kubernetes-basics/expose-intro.html b/docs/tutorials/kubernetes-basics/expose-intro.html index a9d95b2ad5..2f789fe25d 100644 --- a/docs/tutorials/kubernetes-basics/expose-intro.html +++ b/docs/tutorials/kubernetes-basics/expose-intro.html @@ -29,7 +29,7 @@ title: Using a Service to Expose Your App

Kubernetes Pods are mortal. Pods in fact have a lifecycle. When a worker node dies, the Pods running on the Node are also lost. A ReplicationController might then dynamically drive the cluster back to desired state via creation of new Pods to keep your application running. As another example, consider an image-processing backend with 3 replicas. Those replicas are fungible; the front-end system should not care about backend replicas or even if a Pod is lost and recreated. That said, each Pod in a Kubernetes cluster has a unique IP address, even Pods on the same Node, so there needs to be a way of automatically reconciling changes among Pods so that your applications continue to function.

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Enter Services. A Service in Kubernetes is an abstraction which defines a logical set of Pods and a policy by which to access them. Services enable a loose coupling between dependent Pods. A Service is defined using YAML (preferred) or JSON, like all Kubernetes objects. The set of Pods targeted by a Service is usually determined by a LabelSelector (see below for why you might want a Service without including selector in the spec).

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A Service in Kubernetes is an abstraction which defines a logical set of Pods and a policy by which to access them. Services enable a loose coupling between dependent Pods. A Service is defined using YAML (preferred) or JSON, like all Kubernetes objects. The set of Pods targeted by a Service is usually determined by a LabelSelector (see below for why you might want a Service without including selector in the spec).

Although Pods each have a unique IP address, those IPs are not exposed outside the cluster without a Service. Services allow your applications to receive traffic. Services can be exposed in different ways by specifying a type in the ServiceSpec: