Support subnet and iprange arguments on network create

api/ipam.go

@@ -18,6 +18,14 @@ func (client *Client) AllocateIP(ID string) (*net.IPNet, error) {
 	return client.ipamOp(ID, "POST")
 }
 
+func (client *Client) AllocateIPInSubnet(ID string, subnet *net.IPNet) (*net.IPNet, error) {
+	ip, err := client.httpVerb("POST", fmt.Sprintf("/ip/%s/%s", ID, subnet), nil)
+	if err != nil {
+		return nil, err
+	}
+	return parseIP(ip)
+}
+
 // returns an IP for the ID given, or nil if one has not been
 // allocated
 func (client *Client) LookupIP(ID string) (*net.IPNet, error) {

plugin/ipam/driver.go

@@ -1,7 +1,9 @@
 package ipamplugin
 
 import (
+	"fmt"
 	"net"
+	"strings"
 
 	"github.com/docker/libnetwork/ipamapi"
 	"github.com/docker/libnetwork/netlabel"
@@ -29,14 +31,29 @@ func (i *ipam) GetDefaultAddressSpaces() (string, string, error) {
 	return "weavelocal", "weaveglobal", nil
 }
 
-func (i *ipam) RequestPool(addressSpace, pool, subPool string, options map[string]string, v6 bool) (string, *net.IPNet, map[string]string, error) {
+func (i *ipam) RequestPool(addressSpace, pool, subPool string, options map[string]string, v6 bool) (poolname string, subnet *net.IPNet, data map[string]string, err error) {
 	Log.Debugln("RequestPool", addressSpace, pool, subPool, options)
-	cidr, err := i.weave.DefaultSubnet()
-	Log.Debugln("RequestPool returning ", cidr, err)
+	defer func() { Log.Debugln("RequestPool returning", poolname, subnet, data, err) }()
+	if pool == "" {
+		subnet, err = i.weave.DefaultSubnet()
+	} else {
+		_, subnet, err = net.ParseCIDR(pool)
+	}
+	if err != nil {
+		return
+	}
+	iprange := subnet
+	if subPool != "" {
+		if _, iprange, err = net.ParseCIDR(subPool); err != nil {
+			return
+		}
+	}
+	// Cunningly-constructed pool "name" which gives us what we need later
+	poolname = strings.Join([]string{"weave", subnet.String(), iprange.String()}, "-")
 	// Pass back a fake "gateway address"; we don't actually use it,
 	// so just give the network address.
-	data := map[string]string{netlabel.Gateway: cidr.String()}
-	return "weavepool", cidr, data, err
+	data = map[string]string{netlabel.Gateway: subnet.String()}
+	return
 }
 
 func (i *ipam) ReleasePool(poolID string) error {
@@ -44,12 +61,32 @@ func (i *ipam) ReleasePool(poolID string) error {
 	return nil
 }
 
-func (i *ipam) RequestAddress(poolID string, address net.IP, options map[string]string) (*net.IPNet, map[string]string, error) {
+func (i *ipam) RequestAddress(poolID string, address net.IP, options map[string]string) (ip *net.IPNet, _ map[string]string, err error) {
 	Log.Debugln("RequestAddress", poolID, address, options)
-	// Pass magic string to weave IPAM, which then stores the address under its own string
-	ip, err := i.weave.AllocateIP("_")
-	Log.Debugln("allocateIP returned", ip, err)
-	return ip, nil, err
+	defer func() { Log.Debugln("allocateIP returned", ip, err) }()
+	// If we pass magic string "_" to weave IPAM it stores the address under its own string
+	if poolID == "weavepool" { // old-style
+		ip, err = i.weave.AllocateIP("_")
+		return
+	}
+	parts := strings.Split(poolID, "-")
+	if len(parts) != 3 || parts[0] != "weave" {
+		err = fmt.Errorf("Unrecognized pool ID: %s", poolID)
+		return
+	}
+	var subnet, iprange *net.IPNet
+	if _, subnet, err = net.ParseCIDR(parts[1]); err != nil {
+		return
+	}
+	if _, iprange, err = net.ParseCIDR(parts[2]); err != nil {
+		return
+	}
+	// We are lying slightly to IPAM here: the range is not a subnet
+	if ip, err = i.weave.AllocateIPInSubnet("_", iprange); err != nil {
+		return
+	}
+	ip.Mask = subnet.Mask // fix up the subnet we lied about
+	return
 }
 
 func (i *ipam) ReleaseAddress(poolID string, address net.IP) error {

site/plugin.md

@@ -33,32 +33,48 @@ The Weave plugin actually provides *two* network drivers to Docker
 one named `weave` that can only work with one (like Docker's overlay
 driver).
 
+Docker supports creating multiple networks via the plugin, although
+Weave Net provides only one network underneath. So long as the IP
+addresses for each network are on different subnets, containers on one
+network will not be able to communicate with those on a different network.
+
 ### `weavemesh` driver
 
 * Weave handles all co-ordination between hosts (referred to by Docker as a "local scope" driver)
-* Supports only a single network (we create one named `weave` for you automatically)
 * Uses Weave's partition tolerant IPAM
+* User must pick different subnets if creating multiple networks.
 
-If you do create additional networks using the `weavemesh` driver,
-containers attached to them will be able to communicate with
-containers attached to `weave`; there is no isolation between those
-networks.
+We create a network named `weave` for you automatically, using the
+[default subnet](ipam.html#subnets) set for the `weave` router.
+
+To create additional networks using the `weavemesh` driver, pick a
+different subnet and run this command on all hosts:
+
+    $ docker network create --driver=weavemesh --ipam-driver=weavemesh --subnet=<subnet> <network-name>
+
+The subnets you pick must be within the range covered by Weave's [IP
+Address Management](ipam.html#range)
 
 ### `weave` driver
 
 * This runs in what Docker call "global scope"; requires a cluster store
-* Supports multiple networks (these must be created with `docker network create --driver weave ...`)
 * Used with Docker's cluster store based IPAM
+* Docker can coordinate choosing different subnets for multiple networks.
+
+To create a network using this driver, once you have your cluster store set up:
+
+    $ docker network create --driver=weave <network-name>
+
+### <a name="cluster-store"></a>Cluster store
+
+This is the term used by Docker for a distributed key-value store such
+as Consul, Etcd or ZooKeeper.
 
 There's no specific documentation from Docker on using a cluster
 store, but the first part of
 [Getting Started with Docker Multi-host Networking](https://github.com/docker/docker/blob/master/docs/userguide/networking/get-started-overlay.md)
 should point the way.
 
-Note that in the case of multiple networks using the `weave` driver, all containers are
-on the same virtual network but Docker allocates their addresses on
-different subnets so they cannot talk to each other directly.
-
 ## Plugin command-line arguments
 
 If you want to give some arguments to the plugin independently, don't