(docs/dualstack): v1.17 updates

content/en/docs/concepts/services-networking/dual-stack.md

@@ -51,6 +51,7 @@ To enable IPv4/IPv6 dual-stack, enable the `IPv6DualStack` [feature gate](/docs/
       * `--feature-gates="IPv6DualStack=true"`
       * `--cluster-cidr=<IPv4 CIDR>,<IPv6 CIDR>` eg. `--cluster-cidr=10.244.0.0/16,fc00::/24`
       * `--service-cluster-ip-range=<IPv4 CIDR>,<IPv6 CIDR>`
+      * `--node-cidr-mask-size-ipv4|--node-cidr-mask-size-ipv6` defaults to /24 for IPv4 and /64 for IPv6
    * kubelet:
       * `--feature-gates="IPv6DualStack=true"`
    * kube-proxy:
@@ -98,9 +99,7 @@ The use of publicly routable and non-publicly routable IPv6 address blocks is ac
 
 ## Known Issues
 
-   * IPv6 network block assignment uses the default IPv4 CIDR block size (/24)
    * Kubenet forces IPv4,IPv6 positional reporting of IPs (--cluster-cidr)
-   * Dual-stack networking does not function if the `EndpointSlice` feature gate is enabled.
 
 {{% /capture %}}
 

content/en/docs/tasks/network/validate-dual-stack.md

@@ -58,6 +58,41 @@ kubectl get pods pod01 -o go-template --template='{{range .status.podIPs}}{{prin
 a00:100::4
 ```
 
+You can also validate Pod IPs using the Downward API via the `status.podIPs` fieldPath. The following snippet demonstrates how you can expose the Pod IPs via an environment variable called `MY_POD_IPS` within a container.
+
+```
+        env:
+        - name: MY_POD_IPS
+          valueFrom:
+            fieldRef:
+              fieldPath: status.podIPs
+```
+
+The following command prints the value of the `MY_POD_IPS` environment variable from within a container. The value is a comma separated list that corresponds to the Pod's IPv4 and IPv6 addresses.
+```shell
+kubectl exec -it pod01 -- env | grep MY_POD_IPS
+```
+```
+MY_POD_IPS=10.244.1.4,a00:100::4
+```
+
+The Pod's IP addresses will also be written to `/etc/hosts` within a container. The following command executes a cat on `/etc/hosts` on a dual stack Pod. From the output you can verify both the IPv4 and IPv6 IP address for the Pod.
+
+```shell
+kubectl exec -it pod01 -- cat /etc/hosts
+```
+```
+# 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
+10.244.1.4    pod01
+a00:100::4    pod01
+```
+
 ## Validate Services
 
 Create the following Service without the `ipFamily` field set. When this field is not set, the Service gets an IP from the first configured range via `--service-cluster-ip-range` flag on the kube-controller-manager.