diff --git a/lib/charms_ceph/utils.py b/lib/charms_ceph/utils.py
index a3fd276d..e9b289a4 100644
--- a/lib/charms_ceph/utils.py
+++ b/lib/charms_ceph/utils.py
@@ -1481,11 +1481,11 @@ def get_devices(name):
     :returns: Set(device names), which are strings
     """
     if config(name):
-        devices = [l.strip() for l in config(name).split(' ')]
+        devices = [dev.strip() for dev in config(name).split(' ')]
     else:
         devices = []
     storage_ids = storage_list(name)
-    devices.extend((storage_get('location', s) for s in storage_ids))
+    devices.extend((storage_get('location', sid) for sid in storage_ids))
     devices = filter(os.path.exists, devices)
 
     return set(devices)
@@ -1957,6 +1957,9 @@ def _allocate_logical_volume(dev, lv_type, osd_fsid,
     vg_name = None
     if not lvm.is_lvm_physical_volume(pv_dev):
         lvm.create_lvm_physical_volume(pv_dev)
+        if not os.path.exists(pv_dev):
+            # NOTE: trigger rescan to work around bug 1878752
+            rescan_osd_devices()
         if shared:
             vg_name = 'ceph-{}-{}'.format(lv_type,
                                           str(uuid.uuid4()))
diff --git a/tox.ini b/tox.ini
index 20dbbfc5..b835733a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -41,6 +41,11 @@ basepython = python3.7
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 
+[testenv:py38]
+basepython = python3.8
+deps = -r{toxinidir}/requirements.txt
+       -r{toxinidir}/test-requirements.txt
+
 [testenv:py3]
 basepython = python3
 deps = -r{toxinidir}/requirements.txt