(docs/dualstack): v1.17 updates (#17457)

* Add placehold doc updates for dualstack in 1.17 Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Add Downward API and /etc/hosts Pod IP validation Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * remove addressed known issue via k/k pr 85246 Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Remove known issue and add flag as part of k/k 79993 Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * remove follow up placeholders Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Update verbiage Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Make IP addressing consistent throughout the task Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Update to status.podIPs Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com> * Update content/en/docs/tasks/network/validate-dual-stack.md Use set instead of env Co-Authored-By: Khaled Henidak (Kal) <khnidk@outlook.com>
2019-11-22 21:37:50 -08:00
parent 6e6f90acc1
commit 5702296827
2 changed files with 36 additions and 3 deletions
@@ -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 -- set | 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.
@@ -123,4 +158,3 @@ my-service   ClusterIP   fe80:20d::d06b   2001:db8:f100:4002::9d37:c0d7   80:318

 {{% /capture %}}

-