fix create_bridge() bug, patch README install recipe, WEAVE_DOCKER_ARGS=...

README.md

@@ -36,6 +36,7 @@ To run weave on a host, you need to install...
         sudo wget -O /usr/local/bin/weave \
           https://raw.githubusercontent.com/zettio/weave/master/weaver/weave
         sudo chmod a+x /usr/local/bin/weave
+	/usr/bin/docker pull zettio/weave
 
 3. (recommended) ethtool. On many systems this is installed already;
    if not then grab it via your favourite package manager. On some
@@ -55,14 +56,18 @@ two containers, one on each host.
 
 On $HOST1 run (as root)
 
+    host2# export WEAVE_DOCKER_ARGS='--memory=1gb'
     host1# weave launch 10.0.0.1/16
     host1# C=$(weave run 10.0.1.1/24 -t -i ubuntu)
 
-The first line starts the weave router, in a container. This needs to
+The first line sets additional arguments intended to be passed along 
+to the `docker run` command which launches the weave container.  
+
+The next line starts the weave router, in a container. This needs to
 be done once on each host. We tell weave that its IP address should
 be 10.0.0.1, and that the weave network is on 10.0.0.0/16.
 
-The second line starts our application container. We give it an IP
+The third line starts our application container. We give it an IP
 address and network (a subnet of the weave network). `weave run`
 invokes `docker run -d` with all the parameters following the IP
 address and netmask. So we could be launching any container this way;
@@ -79,6 +84,8 @@ unique.
 
 We repeat similar steps on $HOST2...
 
+    host2# export HOST1='<host1_ip_routable_from_host2>'
+    host2# export WEAVE_DOCKER_ARGS='--memory=1gb'
     host2# weave launch 10.0.0.2/16 $HOST1
     host2# C=$(weave run 10.0.1.2/24 -t -i ubuntu)
 
@@ -87,7 +94,7 @@ weave that it should peer with the weave running on $HOST1. We could
 instead have told the weave on $HOST1 to connect to $HOST2, or told
 both about each other. Order doesn't matter here; weave automatically
 (re)connects to peers when they become available. Also, we can tell
-weave to connect to multiple peers by supplying multiple
+weave to connect to multiple peers by supplying multiple space delimited 
 addresses. And we can [add peers dynamically](#dynamic-topologies).
 
 If there is a firewall between $HOST1 and $HOST2, you must open port 

weaver/weave

@@ -29,10 +29,15 @@ command_exists () {
 
 [ $# -gt 0 ] || usage
 
+WEAVE_IMAGE='zettio/weave'
 BRIDGE=weave
 CONTAINER_IFNAME=ethwe
 MTU=65535
 
+# `export WEAVE_DOCKER_ARGS='customer arguments'` 
+# prior to weave launch will permit you to pass along arguments 
+# to the `docker run` command used to launch the weave container
+
 COMMAND=$1
 
 shift 1
@@ -75,7 +80,7 @@ add_nat_rule() {
 
 create_bridge() {
     [ ! -d /sys/class/net/$BRIDGE ] && {
-        ip link add dev $BRIDGE type bridge
+        ip link add name $BRIDGE type bridge
         ip link set dev $BRIDGE address 7a:$(od -txC -An -N5 /dev/random | tr \  : | tail -c+2)
         # Attempting to set the bridge MTU to a high value directly
         # fails. Bridges take the lowest MTU of their interfaces. So
@@ -229,11 +234,11 @@ case "$COMMAND" in
         IPADDR=$1
         shift 1
         case $(docker inspect --format '{{ .State.Running }} {{ .Config.Image }}' weave 2>/dev/null) in
-            "true zettio/weave")
+            "true $WEAVE_IMAGE")
                 echo "Weave is already running." >&2
                 exit 1
                 ;;
-            "false zettio/weave")
+            "false $WEAVE_IMAGE")
                 docker rm weave >/dev/null
                 ;;
             true*)
@@ -255,7 +260,7 @@ case "$COMMAND" in
         # (eth0, wlan0, etc) so the name becomes stable across host
         # restarts.
         MACADDR=`cat /sys/class/net/$BRIDGE/address`
-        CONTAINER=$(docker run --privileged -d --name=weave -p 6783:6783/tcp -p 6783:6783/udp $WEAVE_DOCKER_ARGS zettio/weave -name $MACADDR "$@")
+        CONTAINER=$(docker run --privileged -d --name=weave -p 6783:6783/tcp -p 6783:6783/udp $WEAVE_DOCKER_ARGS $WEAVE_IMAGE -name $MACADDR "$@")
         with_container_netns attach $CONTAINER $IPADDR eth0
         echo $CONTAINER
         ;;
@@ -280,8 +285,8 @@ case "$COMMAND" in
     version)
         # Try the running container first; if no luck try the image
         if ! DOCKERIMAGE=$(docker inspect --format='{{ .Image }}' weave 2>/dev/null) ; then
-            if ! DOCKERIMAGE=$(docker inspect --format='{{ .Id }}' zettio/weave 2>/dev/null) ; then
-                echo "Unable to find zettio/weave image." >&2
+            if ! DOCKERIMAGE=$(docker inspect --format='{{ .Id }}' $WEAVE_IMAGE 2>/dev/null) ; then
+                echo "Unable to find $WEAVE_IMAGE image." >&2
                 exit 1
             fi
         fi