Add s390x to juju kubernetes

cluster/juju/layers/kubernetes-worker/metadata.yaml

@@ -33,10 +33,14 @@ provides:
     interface: kubernetes-cni
     scope: container
 resources:
-  cni:
+  cni-amd64:
+    type: file
+    filename: cni.tgz
+    description: CNI plugins for amd64
+  cni-s390x:
     type: file
     filename: cni.tgz
-    description: CNI plugins
+    description: CNI plugins for s390x
   kubectl:
     type: file
     filename: kubectl.snap

cluster/juju/layers/kubernetes-worker/reactive/kubernetes_worker.py

@@ -179,7 +179,8 @@ def install_cni_plugins():
 
     # Get the resource via resource_get
     try:
-        archive = hookenv.resource_get('cni')
+        resource_name = 'cni-{}'.format(arch())
+        archive = hookenv.resource_get(resource_name)
     except Exception:
         message = 'Error fetching the cni resource.'
         hookenv.log(message)