Merge branch '1.8'

Fixes #2673.

prog/weave-kube/launch.sh

@@ -113,4 +113,7 @@ fi
 mkdir -p /etc/cni/net.d
 /home/weave/weave --local setup-cni
 
+# Expose the weave network so host processes can communicate with pods
+/home/weave/weave --local expose $WEAVE_EXPOSE_IP
+
 wait $WEAVE_PID

site/kube-addon.md

@@ -126,3 +126,6 @@ The list of variables you can set is:
 * IPALLOC\_INIT - set the initialization mode of the [IP Address
   Manager](/site/operational-guide/concepts.md#ip-address-manager)
   (defaults to consensus amongst the KUBE\_PEERS)
+* WEAVE\_EXPOSE\_IP - set the IP address used as a gateway from the
+  Weave network to the host network - this is useful if you are
+  configuring the addon as a static pod.