diff --git a/upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml.template b/upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml.template
index d8c90beb01..bf97dc813b 100644
--- a/upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml.template
+++ b/upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml.template
@@ -97,11 +97,13 @@ spec:
             limits:
               cpu: 100m
               memory: 200Mi
-          {{if .Networking.Weave.MTU }}
           env:
+            - name: IPALLOC_RANGE
+              value: {{ .KubeControllerManager.ClusterCIDR }}
+            {{- if .Networking.Weave.MTU }}
             - name: WEAVE_MTU
               value: "{{ .Networking.Weave.MTU }}"
-          {{end}}
+            {{- end }}
         - name: weave-npc
           image: weaveworks/weave-npc:1.9.7
           resources:
diff --git a/upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml.template b/upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml.template
index ffc78103c8..5748ec56e3 100644
--- a/upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml.template
+++ b/upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml.template
@@ -58,11 +58,13 @@ spec:
             limits:
               cpu: 100m
               memory: 200Mi
-          {{if .Networking.Weave.MTU }}
           env:
+            - name: IPALLOC_RANGE
+              value: {{ .KubeControllerManager.ClusterCIDR }}
+            {{- if .Networking.Weave.MTU }}
             - name: WEAVE_MTU
               value: "{{ .Networking.Weave.MTU }}"
-          {{end}}
+            {{- end }}
         - name: weave-npc
           image: weaveworks/weave-npc:1.9.7
           resources:
diff --git a/upup/pkg/fi/cloudup/bootstrapchannelbuilder.go b/upup/pkg/fi/cloudup/bootstrapchannelbuilder.go
index 95241966eb..3c1d20060a 100644
--- a/upup/pkg/fi/cloudup/bootstrapchannelbuilder.go
+++ b/upup/pkg/fi/cloudup/bootstrapchannelbuilder.go
@@ -280,7 +280,8 @@ func (b *BootstrapChannelBuilder) buildManifest() (*channelsapi.Addons, map[stri
 	if b.cluster.Spec.Networking.Weave != nil {
 		key := "networking.weave"
 
-		version := "1.9.7"
+		// 1.9.8-kops.1 = 1.9.7 plus IPALLOC_RANGE and WEAVE_MTU
+		version := "1.9.8-kops.1"
 
 		{
 			location := key + "/pre-k8s-1.6.yaml"