Explain multiple containers with same name

Two further scenarios described

weavedns/README.md

@@ -124,6 +124,14 @@ $ shell2_ip=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' $shell2
 $ curl -X PUT "http://$dns_ip:6785/name/$shell2/10.1.1.27" -d local_ip=$shell2_ip -d fqdn=shell2.weave.local
 ```
 
+### Registering multiple containers with the same name
+
+This is supported; in the initial implementation weaveDNS will pick one address to return when you ask for the name.  Since weave-dns will remove any container that dies, this is a simple way to implement redundancy.  In the current implementation it does not attempt to do load-balancing.
+
+### Replacing one container with another at the same name
+
+If you would like to deploy a new version of a service, keep the old one running because it has active connections but make all new requests go to the new version, then you can simply start the new server container and then [unregister](https://github.com/zettio/weave/tree/master/weavedns#unregistering) the old one from DNS. And finally, when all connections to the old server have terminated, stop the container as normal.
+
 ### Not watching docker events
 
 By default, the server will watch docker events and remove entries for
@@ -134,6 +142,8 @@ any containers that die. You can tell it not to, by adding
 $ weave launch-dns 10.1.0.2/16 --watch=false
 ```
 
+### Unregistering
+
 You can manually delete entries for a host, by poking weaveDNS's HTTP
 API with e.g., `curl`: