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ExternalName cleanup (#11326)

* Remove old kube-dns note

* ExternalName IP clarification

* Add minor edits for clarity

* corrections

Co-Authored-By: nikopen <42466421+nikopen@users.noreply.github.com>
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nikopen authored and k8s-ci-robot committed Dec 17, 2018
1 parent 3ccbb12 commit 8f6f6731c56780e0a0e907ff02f2c16941df000b
Showing with 7 additions and 6 deletions.
  1. +7 −6 content/en/docs/concepts/services-networking/service.md
@@ -758,13 +758,10 @@ for supported instance types.

### Type ExternalName {#externalname}

{{< note >}}
ExternalName Services are available only with `kube-dns` version 1.7 and later.
{{< /note >}}
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.

Services of type ExternalName map a service to a DNS name (specified using
the `spec.externalName` parameter) rather than to a typical selector like
`my-service` or `cassandra`. This Service definition, for example, would map
This Service definition, for example, maps
the `my-service` Service in the `prod` namespace to `my.database.example.com`:

```yaml
@@ -777,6 +774,10 @@ spec:
type: ExternalName
externalName: my.database.example.com
```
{{< note >}}
ExternalName accepts an IPv4 address string, but as a DNS name comprised of digits, not as an IP address. ExternalNames that resemble IPv4 addresses are not resolved by CoreDNS or ingress-nginx because ExternalName
is intended to specify a canonical DNS name. To hardcode an IP address, consider headless services.
{{< /note >}}

When looking up the host `my-service.prod.svc.cluster.local`, the cluster DNS service
will return a `CNAME` record with the value `my.database.example.com`. Accessing

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