Merge pull request #43477 from tengqm/tune-service

Fix some nits in the service concept page

Author: k8s-ci-robot

content/en/docs/concepts/services-networking/service.md

@@ -175,7 +175,6 @@ spec:
     targetPort: http-web-svc
 ```
 
-
 This works even if there is a mixture of Pods in the Service using a single
 configured name, with the same network protocol available via different
 port numbers. This offers a lot of flexibility for deploying and evolving
@@ -269,7 +268,8 @@ as a destination.
 {{< /note >}}
 
 For an EndpointSlice that you create yourself, or in your own code,
-you should also pick a value to use for the [`endpointslice.kubernetes.io/managed-by`](/docs/reference/labels-annotations-taints/#endpointslicekubernetesiomanaged-by) label.
+you should also pick a value to use for the label
+[`endpointslice.kubernetes.io/managed-by`](/docs/reference/labels-annotations-taints/#endpointslicekubernetesiomanaged-by).
 If you create your own controller code to manage EndpointSlices, consider using a
 value similar to `"my-domain.example/name-of-controller"`. If you are using a third
 party tool, use the name of the tool in all-lowercase and change spaces and other
@@ -283,7 +283,8 @@ managed by Kubernetes' own control plane.
 #### Accessing a Service without a selector {#service-no-selector-access}
 
 Accessing a Service without a selector works the same as if it had a selector.
-In the [example](#services-without-selectors) for a Service without a selector, traffic is routed to one of the two endpoints defined in
+In the [example](#services-without-selectors) for a Service without a selector,
+traffic is routed to one of the two endpoints defined in
 the EndpointSlice manifest: a TCP connection to 10.1.2.3 or 10.4.5.6, on port 9376.
 
 {{< note >}}
@@ -334,8 +335,7 @@ affects the legacy Endpoints API.
 
 In that case, Kubernetes selects at most 1000 possible backend endpoints to store
 into the Endpoints object, and sets an
-{{< glossary_tooltip text="annotation" term_id="annotation" >}} on the
-Endpoints:
+{{< glossary_tooltip text="annotation" term_id="annotation" >}} on the Endpoints:
 [`endpoints.kubernetes.io/over-capacity: truncated`](/docs/reference/labels-annotations-taints/#endpoints-kubernetes-io-over-capacity).
 The control plane also removes that annotation if the number of backend Pods drops below 1000.
 
@@ -349,7 +349,8 @@ The same API limit means that you cannot manually update an Endpoints to have mo
 {{< feature-state for_k8s_version="v1.20" state="stable" >}}
 
 The `appProtocol` field provides a way to specify an application protocol for
-each Service port. This is used as a hint for implementations to offer richer behavior for protocols that they understand.
+each Service port. This is used as a hint for implementations to offer
+richer behavior for protocols that they understand.
 The value of this field is mirrored by the corresponding
 Endpoints and EndpointSlice objects.
 
@@ -365,8 +366,6 @@ This field follows standard Kubernetes label syntax. Valid values are one of:
 |----------|-------------|
 | `kubernetes.io/h2c` | HTTP/2 over cleartext as described in [RFC 7540](https://www.rfc-editor.org/rfc/rfc7540) |
 
-
-
 ### Multi-port Services
 
 For some Services, you need to expose more than one port.
@@ -402,7 +401,6 @@ also start and end with an alphanumeric character.
 For example, the names `123-abc` and `web` are valid, but `123_abc` and `-web` are not.
 {{< /note >}}
 
-
 ## Service type  {#publishing-services-service-types}
 
 For some parts of your application (for example, frontends) you may want to expose a
@@ -417,7 +415,8 @@ The available `type` values and their behaviors are:
 : Exposes the Service on a cluster-internal IP. Choosing this value
   makes the Service only reachable from within the cluster. This is the
   default that is used if you don't explicitly specify a `type` for a Service.
-  You can expose the Service to the public internet using an [Ingress](/docs/concepts/services-networking/ingress/) or a
+  You can expose the Service to the public internet using an
+  [Ingress](/docs/concepts/services-networking/ingress/) or a
   [Gateway](https://gateway-api.sigs.k8s.io/).
 
 [`NodePort`](#type-nodeport)
@@ -439,8 +438,7 @@ The available `type` values and their behaviors are:
 The `type` field in the Service API is designed as nested functionality - each level
 adds to the previous. However there is an exception to this nested design. You can
 define a `LoadBalancer` Service by
-[disabling the load balancer `NodePort` allocation.](/docs/concepts/services-networking/service/#load-balancer-nodeport-allocation)
-
+[disabling the load balancer `NodePort` allocation](/docs/concepts/services-networking/service/#load-balancer-nodeport-allocation).
 
 ### `type: ClusterIP` {#type-clusterip}
 
@@ -510,11 +508,13 @@ spec:
   selector:
     app.kubernetes.io/name: MyApp
   ports:
-      # By default and for convenience, the `targetPort` is set to the same value as the `port` field.
     - port: 80
+      # By default and for convenience, the `targetPort` is set to
+      # the same value as the `port` field.
       targetPort: 80
       # Optional field
-      # By default and for convenience, the Kubernetes control plane will allocate a port from a range (default: 30000-32767)
+      # By default and for convenience, the Kubernetes control plane
+      # will allocate a port from a range (default: 30000-32767)
       nodePort: 30007
 ```
 
@@ -541,8 +541,7 @@ control plane).
 
 If you want to specify particular IP address(es) to proxy the port, you can set the
 `--nodeport-addresses` flag for kube-proxy or the equivalent `nodePortAddresses`
-field of the
-[kube-proxy configuration file](/docs/reference/config-api/kube-proxy-config.v1alpha1/)
+field of the [kube-proxy configuration file](/docs/reference/config-api/kube-proxy-config.v1alpha1/)
 to particular IP block(s).
 
 This flag takes a comma-delimited list of IP blocks (e.g. `10.0.0.0/8`, `192.0.2.0/25`)
@@ -556,7 +555,8 @@ This means that kube-proxy should consider all available network interfaces for
 {{< note >}}
 This Service is visible as `<NodeIP>:spec.ports[*].nodePort` and `.spec.clusterIP:spec.ports[*].port`.
 If the `--nodeport-addresses` flag for kube-proxy or the equivalent field
-in the kube-proxy configuration file is set, `<NodeIP>` would be a filtered node IP address (or possibly IP addresses).
+in the kube-proxy configuration file is set, `<NodeIP>` would be a filtered
+node IP address (or possibly IP addresses).
 {{< /note >}}
 
 ### `type: LoadBalancer` {#loadbalancer}
@@ -610,7 +610,8 @@ set is ignored.
 {{< note >}}
 The`.spec.loadBalancerIP` field for a Service was deprecated in Kubernetes v1.24.
 
-This field was under-specified and its meaning varies across implementations. It also cannot support dual-stack networking. This field may be removed in a future API version.
+This field was under-specified and its meaning varies across implementations.
+It also cannot support dual-stack networking. This field may be removed in a future API version.
 
 If you're integrating with a provider that supports specifying the load balancer IP address(es)
 for a Service via a (provider specific) annotation, you should switch to doing that.
@@ -684,117 +685,97 @@ depending on the cloud service provider you're using:
 {{% tab name="Default" %}}
 Select one of the tabs.
 {{% /tab %}}
+
 {{% tab name="GCP" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        networking.gke.io/load-balancer-type: "Internal"
-[...]
+  name: my-service
+  annotations:
+      networking.gke.io/load-balancer-type: "Internal"
 ```
-
 {{% /tab %}}
 {{% tab name="AWS" %}}
 
 ```yaml
-[...]
 metadata:
     name: my-service
     annotations:
         service.beta.kubernetes.io/aws-load-balancer-internal: "true"
-[...]
 ```
 
 {{% /tab %}}
 {{% tab name="Azure" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        service.beta.kubernetes.io/azure-load-balancer-internal: "true"
-[...]
+  name: my-service
+  annotations:
+      service.beta.kubernetes.io/azure-load-balancer-internal: "true"
 ```
 
 {{% /tab %}}
 {{% tab name="IBM Cloud" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        service.kubernetes.io/ibm-load-balancer-cloud-provider-ip-type: "private"
-[...]
+  name: my-service
+  annotations:
+      service.kubernetes.io/ibm-load-balancer-cloud-provider-ip-type: "private"
 ```
 
 {{% /tab %}}
 {{% tab name="OpenStack" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        service.beta.kubernetes.io/openstack-internal-load-balancer: "true"
-[...]
+  name: my-service
+  annotations:
+    service.beta.kubernetes.io/openstack-internal-load-balancer: "true"
 ```
 
 {{% /tab %}}
 {{% tab name="Baidu Cloud" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        service.beta.kubernetes.io/cce-load-balancer-internal-vpc: "true"
-[...]
+  name: my-service
+  annotations:
+    service.beta.kubernetes.io/cce-load-balancer-internal-vpc: "true"
 ```
 
 {{% /tab %}}
 {{% tab name="Tencent Cloud" %}}
 
 ```yaml
-[...]
 metadata:
   annotations:
     service.kubernetes.io/qcloud-loadbalancer-internal-subnetid: subnet-xxxxx
-[...]
 ```
 
 {{% /tab %}}
 {{% tab name="Alibaba Cloud" %}}
 
 ```yaml
-[...]
 metadata:
   annotations:
     service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type: "intranet"
-[...]
 ```
 
 {{% /tab %}}
 {{% tab name="OCI" %}}
 
 ```yaml
-[...]
 metadata:
-    name: my-service
-    annotations:
-        service.beta.kubernetes.io/oci-load-balancer-internal: true
-[...]
+  name: my-service
+  annotations:
+      service.beta.kubernetes.io/oci-load-balancer-internal: true
 ```
 {{% /tab %}}
 {{< /tabs >}}
 
 ### `type: ExternalName` {#externalname}
 
-
-
 Services of type ExternalName map a Service to a DNS name, not to a typical selector such as
 `my-service` or `cassandra`. You specify these Services with the `spec.externalName` parameter.
 
@@ -813,11 +794,14 @@ spec:
 ```
 
 {{< note >}}
-A Service of `type: ExternalName` accepts an IPv4 address string, but treats that string as a DNS name comprised of digits,
-not as an IP address (the internet does not however allow such names in DNS). Services with external names that resemble IPv4
+A Service of `type: ExternalName` accepts an IPv4 address string,
+but treats that string as a DNS name comprised of digits,
+not as an IP address (the internet does not however allow such names in DNS).
+Services with external names that resemble IPv4
 addresses are not resolved by DNS servers.
 
-If you want to map a Service directly to a specific IP address, consider using [headless Services](#headless-services).
+If you want to map a Service directly to a specific IP address, consider using
+[headless Services](#headless-services).
 {{< /note >}}
 
 When looking up the host `my-service.prod.svc.cluster.local`, the cluster DNS Service
@@ -883,7 +867,8 @@ finding a Service: environment variables and DNS.
 When a Pod is run on a Node, the kubelet adds a set of environment variables
 for each active Service. It adds `{SVCNAME}_SERVICE_HOST` and `{SVCNAME}_SERVICE_PORT` variables,
 where the Service name is upper-cased and dashes are converted to underscores.
-It also supports variables (see [makeLinkVariables](https://github.com/kubernetes/kubernetes/blob/dd2d12f6dc0e654c15d5db57a5f9f6ba61192726/pkg/kubelet/envvars/envvars.go#L72))
+It also supports variables
+(see [makeLinkVariables](https://github.com/kubernetes/kubernetes/blob/dd2d12f6dc0e654c15d5db57a5f9f6ba61192726/pkg/kubelet/envvars/envvars.go#L72))
 that are compatible with Docker Engine's
 "_[legacy container links](https://docs.docker.com/network/links/)_" feature.
 
@@ -1015,14 +1000,17 @@ about the [Service API object](/docs/reference/generated/kubernetes-api/{{< para
 ## {{% heading "whatsnext" %}}
 
 Learn more about Services and how they fit into Kubernetes:
-* Follow the [Connecting Applications with Services](/docs/tutorials/services/connect-applications-service/) tutorial.
+
+* Follow the [Connecting Applications with Services](/docs/tutorials/services/connect-applications-service/)
+  tutorial.
 * Read about [Ingress](/docs/concepts/services-networking/ingress/), which
   exposes HTTP and HTTPS routes from outside the cluster to Services within
   your cluster.
 * Read about [Gateway](https://gateway-api.sigs.k8s.io/), an extension to
   Kubernetes that provides more flexibility than Ingress.
 
 For more context, read the following:
+
 * [Virtual IPs and Service Proxies](/docs/reference/networking/virtual-ips/)
 * [EndpointSlices](/docs/concepts/services-networking/endpoint-slices/)
 * [Service API reference](/docs/reference/kubernetes-api/service-resources/service-v1/)