diff --git a/.zuul.yaml b/.zuul.yaml
index b3037e9..6909233 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -1,5 +1,5 @@
 - project:
     templates:
-      - python35-charm-jobs
+      - python36-charm-jobs
       - openstack-python3-ussuri-jobs
       - openstack-cover-jobs
diff --git a/requirements.txt b/requirements.txt
index b786b42..a68620f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,6 +9,7 @@
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
 
 # Build requirements
+cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
 charm-tools==2.8.3
 
 simplejson
diff --git a/src/README.md b/src/README.md
index 2e70115..90e79aa 100644
--- a/src/README.md
+++ b/src/README.md
@@ -50,8 +50,10 @@ host will never be overwritten.
 
 ## Deployment
 
-To deploy, add a relation to the cinder charm:
+Specify a block device (here we choose `/dev/sdb`) and then add a relation to
+the cinder charm:
 
+    juju deploy --config block-device=sdb cinder-lvm
     juju add-relation cinder-lvm:storage-backend cinder:storage-backend
 
 # Documentation
diff --git a/src/config.yaml b/src/config.yaml
index c8caab5..c341829 100644
--- a/src/config.yaml
+++ b/src/config.yaml
@@ -102,7 +102,7 @@ options:
       Volume group name to use within LVM. If empty, the volume group name
       will be constructed by concatenating the 'alias' config option to the
       prefix 'cinder-volumes-'.
-  backend-name:
+  volume-backend-name:
     type: string
     default:
     description: |
diff --git a/src/lib/charm/openstack/cinder_lvm.py b/src/lib/charm/openstack/cinder_lvm.py
index d03b7a5..6b229c6 100644
--- a/src/lib/charm/openstack/cinder_lvm.py
+++ b/src/lib/charm/openstack/cinder_lvm.py
@@ -63,7 +63,7 @@ def get_backend_name():
     hostname = socket.gethostname()
     alias = ch_hookenv.config('alias')
     unique_backend = ch_hookenv.config('unique-backend')
-    backend_name = ch_hookenv.config('backend-name')
+    backend_name = ch_hookenv.config('volume-backend-name')
 
     if backend_name:
         pass
diff --git a/tox.ini b/tox.ini
index 22159df..fb00734 100644
--- a/tox.ini
+++ b/tox.ini
@@ -55,11 +55,6 @@ basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
 commands = stestr run --slowest {posargs}
 
-[testenv:py35]
-basepython = python3.5
-deps = -r{toxinidir}/test-requirements.txt
-commands = stestr run --slowest {posargs}
-
 [testenv:py36]
 basepython = python3.6
 deps = -r{toxinidir}/test-requirements.txt
diff --git a/unit_tests/test_lib_charm_openstack_cinder_lvm.py b/unit_tests/test_lib_charm_openstack_cinder_lvm.py
index 0f23697..a64c1c3 100644
--- a/unit_tests/test_lib_charm_openstack_cinder_lvm.py
+++ b/unit_tests/test_lib_charm_openstack_cinder_lvm.py
@@ -207,9 +207,10 @@ class TestCinderLVMCharm(test_utils.PatchHelper):
         self.assertNotIn('a', list(x[0] for x in config))
 
     def test_cinder_vg_and_backend(self):
-        base = {'volume-group': 'test-vg', 'backend-name': 'test-bn'}
+        base = {'volume-group': 'test-vg', 'volume-backend-name': 'test-bn'}
         self._patch_config_and_charm(base)
-        self.assertEqual(cinder_lvm.get_backend_name(), base['backend-name'])
+        self.assertEqual(cinder_lvm.get_backend_name(),
+                         base['volume-backend-name'])
         self.assertEqual(cinder_lvm.get_volume_group_name(),
                          base['volume-group'])