Added README

README.md

@@ -0,0 +1,45 @@
+# Weave DNS server
+
+The Weave DNS server answers name queries in a Weave network. It is
+run per-host, to be supplied as the nameserver for containers on that
+host. It is then told about hostnames for the local containers. For
+other names it will ask the other weave hosts, or fall back to using
+the host's configured name server.
+
+## Use
+
+The Weave DNS container should be started after the Weave router --
+i.e., after running `weave launch` -- and joined to the Weave network.
+
+In general, it should be given an IP in the same subnet as the
+router. To watch for container events it must have the docker socker
+mounted.
+
+```bash
+$ weave launch 10.0.0.1/16
+$ weave run 10.0.0.2/16 --name=weavedns -v /var/run/docker.sock:/var/run/docker.sock zettio/weavedns
+```
+
+The docker IP for the container can then be provided as the `--dns` value
+for other containers:
+
+```bash
+$ dns_ip=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' weavedns)
+$ shell1=$(weave run 10.0.1.2/24 --dns=$dns_ip -t ubuntu /bin/bash)
+```
+
+To associate a hostname with an IP, use an HTTP PUT to the DNS server:
+
+```bash
+$ shell1_ip=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' $shell1)
+$ curl -X PUT "http://$dns_ip:6785/name/$shell1/10.0.1.2?fqdn=shell1.weave&routing_prefix=24&local_ip=$shell1_ip"
+```
+
+You should now be able to look up the name:
+
+```bash
+$ dig @$dns_ip +short shell1.weave
+```
+
+By default, the server will also watch docker events and remove
+entries for any containers that die.