1. Sync the service-networking folder from 1.14 version

2. Sync the service-networking folder files with 1.16 version en document
3. Changed some files structure for easily review
4. Add the necessary documents
5. Add the runtime-class file

content/zh/docs/concepts/services-networking/_index.md

@@ -0,0 +1,4 @@
+---
+title: "服务、负载均衡和联网"
+weight: 80
+---

content/zh/docs/concepts/services-networking/add-entries-to-pod-etc-hosts-with-host-aliases.md

@@ -1,75 +1,180 @@
 ---
-approvers:
-- rickypai
-- thockin
 title: 使用 HostAliases 向 Pod /etc/hosts 文件添加条目
-redirect_from:
-- "/docs/user-guide/add-entries-to-pod-etc-hosts-with-host-aliases/"
-- "/docs/user-guide/add-entries-to-pod-etc-hosts-with-host-aliases.md"
+content_template: templates/concept
+weight: 60
 ---
 
 {{< toc >}}
 
+{{% capture overview %}}
 
+<!--
+Adding entries to a Pod's /etc/hosts file provides Pod-level override of hostname resolution when DNS and other options are not applicable. In 1.7, users can add these custom entries with the HostAliases field in PodSpec.
+
+Modification not using HostAliases is not suggested because the file is managed by Kubelet and can be overwritten on during Pod creation/restart.
+-->
 
 当 DNS 配置以及其它选项不合理的时候，通过向 Pod 的 /etc/hosts 文件中添加条目，可以在 Pod 级别覆盖对主机名的解析。在 1.7 版本，用户可以通过 PodSpec 的 HostAliases 字段来添加这些自定义的条目。
 
 建议通过使用 HostAliases 来进行修改，因为该文件由 Kubelet 管理，并且可以在 Pod 创建/重启过程中被重写。 
+{{% /capture %}}
 
+{{% capture body %}}
 
+<!--
+## Default Hosts File Content
 
+Let's start an Nginx Pod which is assigned a Pod IP:
+-->
 ## 默认 hosts 文件内容
 
 让我们从一个 Nginx Pod 开始，给该 Pod 分配一个 IP：
 
+```shell
+kubectl run nginx --image nginx --generator=run-pod/v1
+```
+
+```shell
+pod/nginx created
 ```
-$ kubectl get pods --output=wide
+
+<!--
+Examine a Pod IP:
+-->
+检查Pod IP：
+
+```shell
+kubectl get pods --output=wide
+```
+
+```shell
 NAME     READY     STATUS    RESTARTS   AGE    IP           NODE
 nginx    1/1       Running   0          13s    10.200.0.4   worker0
 ```
 
+<!--
+The hosts file content would look like this:
+-->
+
+主机文件的内容如下所示：
+
+```shell
+kubectl exec nginx -- cat /etc/hosts
+```
 
+```none
+# Kubernetes-managed hosts file.
+127.0.0.1	localhost
+::1	localhost ip6-localhost ip6-loopback
+fe00::0	ip6-localnet
+fe00::0	ip6-mcastprefix
+fe00::1	ip6-allnodes
+fe00::2	ip6-allrouters
+10.200.0.4	nginx
+```
 
+<!--
+By default, the `hosts` file only includes IPv4 and IPv6 boilerplates like
+`localhost` and its own hostname.
+-->
 默认，hosts 文件只包含 ipv4 和 ipv6 的样板内容，像 `localhost` 和主机名称。
 
+<!--
+## Adding Additional Entries with HostAliases
+
+In addition to the default boilerplate, we can add additional entries to the
+`hosts` file to resolve `foo.local`, `bar.local` to `127.0.0.1` and `foo.remote`,
+`bar.remote` to `10.1.2.3`, we can by adding HostAliases to the Pod under
+`.spec.hostAliases`:
+-->
+
 ## 通过 HostAliases 增加额外的条目
 
+除了默认的样板内容，我们可以向 hosts 文件添加额外的条目，将 `foo.local`、 `bar.local` 解析为`127.0.0.1`，
+将 `foo.remote`、 `bar.remote` 解析为 `10.1.2.3`，我们可以在 `.spec.hostAliases` 下为 Pod 添加 HostAliases。
+
+{{< codenew file="service/networking/hostaliases-pod.yaml" >}}
 
+<!--
+This Pod can be started with the following commands:
+-->
 
-除了默认的样板内容，我们可以向 hosts 文件添加额外的条目，将 `foo.local`、 `bar.local` 解析为`127.0.0.1`，将 `foo.remote`、 `bar.remote` 解析为 `10.1.2.3`，我们可以在 `.spec.hostAliases` 下为 Pod 添加 HostAliases。
+可以使用以下命令启动此Pod：
+
+```shell
+kubectl apply -f hostaliases-pod.yaml
+```
 
-{{< code file="hostaliases-pod.yaml" >}}
+```shell
+pod/hostaliases-pod created
+```
+
+<!--
+Examine a Pod IP and status:
+-->
+检查Pod IP 和状态：
+
+```shell
+kubectl get pod --output=wide
+```
+
+```shell
+NAME                           READY     STATUS      RESTARTS   AGE       IP              NODE
+hostaliases-pod                0/1       Completed   0          6s        10.200.0.5      worker0
+```
+
+<!--
+The `hosts` file content would look like this:
+-->
 
 hosts 文件的内容看起来类似如下这样：
 
+```shell
+kubectl logs hostaliases-pod
 ```
-$ kubectl logs hostaliases-pod
+
+```none
 # Kubernetes-managed hosts file.
 127.0.0.1	localhost
 ::1	localhost ip6-localhost ip6-loopback
 fe00::0	ip6-localnet
 fe00::0	ip6-mcastprefix
 fe00::1	ip6-allnodes
 fe00::2	ip6-allrouters
-10.200.0.4	hostaliases-pod
-127.0.0.1	foo.local
-127.0.0.1	bar.local
-10.1.2.3	foo.remote
-10.1.2.3	bar.remote
-```
+10.200.0.5	hostaliases-pod
 
+# Entries added by HostAliases.
+127.0.0.1	foo.local	bar.local
+10.1.2.3	foo.remote	bar.remote
+```
 
+<!--
+With the additional entries specified at the bottom.
+-->
 
 在最下面额外添加了一些条目。
 
-## 限制
+<!--
+With the additional entries specified at the bottom.
 
-在 1.7 版本，如果 Pod 启用 hostNetwork，那么将不能使用这个特性，因为 kubelet 只管理非 hostNetwork 类型 Pod 的 hosts 文件。目前正在讨论要改变这个情况。
+## Why Does Kubelet Manage the Hosts File?
 
+Kubelet [manages](https://github.com/kubernetes/kubernetes/issues/14633) the
+`hosts` file for each container of the Pod to prevent Docker from
+[modifying](https://github.com/moby/moby/issues/17190) the file after the
+containers have already been started.
 
+Because of the managed-nature of the file, any user-written content will be
+overwritten whenever the `hosts` file is remounted by Kubelet in the event of
+a container restart or a Pod reschedule. Thus, it is not suggested to modify
+the contents of the file.
+-->
 
 ## 为什么 Kubelet 管理 hosts文件？
 
 kubelet [管理](https://github.com/kubernetes/kubernetes/issues/14633) Pod 中每个容器的 hosts 文件，避免 Docker 在容器已经启动之后去 [修改](https://github.com/moby/moby/issues/17190) 该文件。
 
 因为该文件是托管性质的文件，无论容器重启或 Pod 重新调度，用户修改该 hosts 文件的任何内容，都会在 Kubelet 重新安装后被覆盖。因此，不建议修改该文件的内容。
+
+{{% /capture %}}
+