Merge pull request #1135 from weaveworks/462-ipv6-connection

docs: add docs about ipv6

docs/use_tf_controller/with-ipv6.md

@@ -0,0 +1,16 @@
+# Use TF-Controller with IPv6 addresses.
+
+TF-Controller uses pod IPv4 address to generate the in-cluster hostname to
+communicate with the runner instance. This logic fails when the runner pod has
+IPv6 address instead of IPv4.
+
+The TF-Controller has a flag to use pod subdomain resolution instead of an IP
+address, with that enabled the controller will use cluster subdomains, and it
+works with IPv6 addresses as the resolution is happening at cluster level.
+
+To enable this feature, you can set `usePodSubdomainResolution` to `true` in the
+Helm values file:
+
+```yaml
+usePodSubdomainResolution: true
+```