Fix nagios checks.

cluster/juju/layers/kubernetes-master/reactive/kubernetes_master.py

@@ -49,6 +49,11 @@ from charmhelpers.fetch import apt_install
 from charmhelpers.contrib.charmsupport import nrpe
 
 
+# Override the default nagios shortname regex to allow periods, which we
+# need because our bin names contain them (e.g. 'snap.foo.daemon'). The
+# default regex in charmhelpers doesn't allow periods, but nagios itself does.
+nrpe.Check.shortname_re = '[\.A-Za-z0-9-_]+$'
+
 os.environ['PATH'] += os.pathsep + os.path.join(os.sep, 'snap', 'bin')